Merge branch 'develop' into peerDAS-do-not-merge

* `data_column.go`: Factorize declarations (no functional changes).

* Verification for data columns: Do not recompute again if already done.

* `SaveDataColumns`: Delete because unused.

* `MissingDataColumns`: Use `DataColumnStorageSummarizer` instead of `DataColumnStorage`

* `TestFetchDataColumnsFromPeers`: Move trusted setup load out of the loop for optimization.

* `TestFetchDataColumnsFromPeers`: Use fulu block instead of deneb block.

* `fetchDataColumnsFromPeers`: Use functions already implemented in the `sync` package instead of duplicated them here.

* `fetchDataColumnsFromPeers` ==> `fetchMissingDataColumnsFromPeers`.

* Data columns initial sync: simplify

* Requests data columns by range: Move from initial sync to sync package.

Since it will eventually be used by the backfill package, and
the backfill packages does not depend on the initial sync package.

.bazelrc

@@ -22,6 +22,7 @@ coverage --define=coverage_enabled=1
 build --workspace_status_command=./hack/workspace_status.sh
 
 build --define blst_disabled=false
+build --compilation_mode=opt
 run --define blst_disabled=false
 
 build:blst_disabled --define blst_disabled=true

.bazelversion

@@ -1 +1 @@
-7.1.0
+7.4.1

.buildkite-bazelrc

@@ -12,8 +12,7 @@
 build:remote-cache --remote_download_minimal
 build:remote-cache --remote_build_event_upload=minimal
 build:remote-cache --remote_cache=grpc://bazel-remote-cache:9092
-# Does not work with rules_oci. See https://github.com/bazel-contrib/rules_oci/issues/292
-#build:remote-cache --experimental_remote_downloader=grpc://bazel-remote-cache:9092
+build:remote-cache --experimental_remote_downloader=grpc://bazel-remote-cache:9092
 build:remote-cache --remote_local_fallback
 build:remote-cache --experimental_remote_cache_async
 build:remote-cache --experimental_remote_merkle_tree_cache
@@ -51,7 +50,7 @@ build:nostamp --nostamp
 
 # Build metadata
 build --build_metadata=ROLE=CI
-build --build_metadata=REPO_URL=https://github.com/prysmaticlabs/prysm.git
+build --build_metadata=REPO_URL=https://github.com/OffchainLabs/prysm.git
 build --workspace_status_command=./hack/workspace_status_ci.sh
 
 # Buildbuddy

.deepsource.toml

@@ -11,7 +11,7 @@ name = "go"
 enabled = true
 
 [analyzers.meta]
-import_paths = ["github.com/prysmaticlabs/prysm/v5"]
+import_paths = ["github.com/OffchainLabs/prysm/v6"]
 
 [[analyzers]]
 name = "test-coverage"

.github/PULL_REQUEST_TEMPLATE.md

@@ -10,6 +10,7 @@
    in review.
 4. Note that PRs updating dependencies and new Go versions are not accepted.
    Please file an issue instead.
+5. A changelog entry is required for user facing issues.
 -->
 
 **What type of PR is this?**
@@ -28,3 +29,9 @@
 Fixes #
 
 **Other notes for review**
+
+**Acknowledgements**
+
+- [ ] I have read [CONTRIBUTING.md](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md).
+- [ ] I have included a uniquely named [changelog fragment file](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md#maintaining-changelogmd).
+- [ ] I have added a description to this PR with sufficient context for reviewers to understand this PR.

.github/actions/gomodtidy/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.21-alpine
+FROM golang:1.24-alpine
 
 COPY entrypoint.sh /entrypoint.sh
 

.github/workflows/changelog.yml

@@ -0,0 +1,34 @@
+# This workflow will build a golang project
+# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-go
+
+name: changelog
+
+on:
+  pull_request:
+    branches: [ "develop" ]
+
+jobs:
+  run-changelog-check:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
+
+      - name: Download unclog binary
+        uses: dsaltares/fetch-gh-release-asset@aa2ab1243d6e0d5b405b973c89fa4d06a2d0fff7 # 1.1.2
+        with:
+          repo: OffchainLabs/unclog
+          version: "tags/v0.1.3"
+          file: "unclog"
+
+      - name: Get new changelog files
+        id: new-changelog-files
+        uses: OffchainLabs/gh-action-changed-files@9200e69727eb73eb060652b19946b8a2fdfb654b # v4.0.8
+        with:
+          files: |
+            changelog/**.md
+
+      - name: Run lint command
+        env:
+          ALL_ADDED_MARKDOWN: ${{ steps.new-changelog-files.outputs.added_files }}
+        run: chmod +x unclog && ./unclog check -fragment-env=ALL_ADDED_MARKDOWN

.github/workflows/clang-format.yml

@@ -0,0 +1,21 @@
+name: Protobuf Format
+
+on: 
+  push:
+    branches: [ '*' ]
+  pull_request:
+    branches: [ '*' ]
+  merge_group:
+    types: [checks_requested]
+
+jobs:
+  clang-format-checking:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      # Is this step failing for you? 
+      # Run: clang-format -i proto/**/*.proto
+      # See: https://clang.llvm.org/docs/ClangFormat.html
+      - uses: RafikFarhad/clang-format-github-action@v3
+        with:
+          sources: "proto/**/*.proto"

.github/workflows/fuzz.yml

@@ -16,7 +16,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v4
         with:
-          go-version: '1.21.5'
+          go-version: '1.23.5'
       - id: list
         uses: shogo82148/actions-go-fuzz/list@v0
         with:
@@ -36,7 +36,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v4
         with:
-          go-version: '1.21.5'
+          go-version: '1.23.5'
       - uses: shogo82148/actions-go-fuzz/run@v0
         with:
           packages: ${{ matrix.package }}

.github/workflows/go.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Go mod tidy checker
         id: gomodtidy
@@ -27,34 +27,34 @@ jobs:
       GO111MODULE: on
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
-      - name: Set up Go 1.21
-        uses: actions/setup-go@v3
+        uses: actions/checkout@v4
+      - name: Set up Go 1.24
+        uses: actions/setup-go@v4
         with:
-          go-version: '1.21.5'
+          go-version: '1.24.0'
       - name: Run Gosec Security Scanner
         run: | # https://github.com/securego/gosec/issues/469
           export PATH=$PATH:$(go env GOPATH)/bin
-          go install github.com/securego/gosec/v2/cmd/gosec@v2.15.0
-          gosec -exclude-generated -exclude=G307 -exclude-dir=crypto/bls/herumi ./...
+          go install github.com/securego/gosec/v2/cmd/gosec@v2.22.1
+          gosec -exclude-generated -exclude=G307,G115 -exclude-dir=crypto/bls/herumi ./...
 
   lint:
     name: Lint
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
-      - name: Set up Go 1.21
-        uses: actions/setup-go@v3
+      - name: Set up Go 1.24
+        uses: actions/setup-go@v4
         with:
-          go-version: '1.21.5'
+          go-version: '1.24.0'
           id: go
 
       - name: Golangci-lint
-        uses: golangci/golangci-lint-action@v3
+        uses: golangci/golangci-lint-action@v5
         with:
-          version: v1.55.2
+          version: v1.64.5
           args: --config=.golangci.yml --out-${NO_FUTURE}format colored-line-number
 
   build:
@@ -62,13 +62,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Set up Go 1.x
-        uses: actions/setup-go@v2
+        uses: actions/setup-go@v4
         with:
-          go-version: '1.21.5'
+          go-version: '1.24.0'
         id: go
 
       - name: Check out code into the Go module directory
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Get dependencies
         run: |

.gitignore

@@ -41,3 +41,6 @@ jwt.hex
 
 # manual testing
 tmp
+
+# spectest coverage reports
+report.txt

.golangci.yml

@@ -1,28 +1,20 @@
 run:
-  skip-files:
+  timeout: 10m
+  go: '1.23.5'
+
+issues:
+  exclude-files:
     - validator/web/site_data.go
     - .*_test.go
-  skip-dirs:
+  exclude-dirs:
     - proto
     - tools/analyzers
-  timeout: 10m
-  go: '1.21.5'
 
 linters:
   enable-all: true
   disable:
     # Deprecated linters:
-    - deadcode
-    - exhaustivestruct
-    - golint
     - govet
-    - ifshort
-    - interfacer
-    - maligned
-    - nosnakecase
-    - scopelint
-    - structcheck
-    - varcheck
 
     # Disabled for now:
     - asasalint
@@ -34,7 +26,8 @@ linters:
     - dogsled
     - dupl
     - durationcheck
-    - errorlint
+    - errname
+    - err113
     - exhaustive
     - exhaustruct
     - forbidigo
@@ -48,16 +41,17 @@ linters:
     - gocyclo
     - godot
     - godox
-    - goerr113
     - gofumpt
-    - gomnd
     - gomoddirectives
+    - gosec
     - inamedparam
     - interfacebloat
+    - intrange
     - ireturn
     - lll
     - maintidx
     - makezero
+    - mnd
     - musttag
     - nakedret
     - nestif
@@ -72,13 +66,16 @@ linters:
     - predeclared
     - promlinter
     - protogetter
+    - recvcheck
     - revive
+    - spancheck
     - staticcheck
     - stylecheck
     - tagalign
     - tagliatelle
     - thelper
     - unparam
+    - usetesting
     - varnamelen
     - wrapcheck
     - wsl

.policy.yml

@@ -26,7 +26,6 @@ approval_rules:
       only_changed_files:
         paths:
           - "*pb.go"
-          - "*pb.gw.go"
           - "*.bazel"
     options:
       ignore_commits_by:
@@ -69,7 +68,6 @@ approval_rules:
       changed_files:
         ignore:
           - "*pb.go"
-          - "*pb.gw.go"
           - "*.bazel"
     options:
       ignore_commits_by:

.travis.yml

@@ -1,5 +1,5 @@
 language: go
-go_import_path: github.com/prysmaticlabs/prysm
+go_import_path: github.com/OffchainLabs/prysm
 sudo: false
 matrix:
   include:

BUILD.bazel

@@ -6,13 +6,13 @@ load("@io_bazel_rules_go//go:def.bzl", "nogo")
 load("@bazel_skylib//rules:common_settings.bzl", "string_setting")
 load("@prysm//tools/nogo_config:def.bzl", "nogo_config_exclude")
 
-prefix = "github.com/prysmaticlabs/prysm"
+prefix = "github.com/OffchainLabs/prysm"
 
 exports_files([
     "LICENSE.md",
 ])
 
-# gazelle:prefix github.com/prysmaticlabs/prysm/v5
+# gazelle:prefix github.com/OffchainLabs/prysm/v6
 # gazelle:map_kind go_library go_library @prysm//tools/go:def.bzl
 # gazelle:map_kind go_test go_test @prysm//tools/go:def.bzl
 # gazelle:map_kind go_repository go_repository @prysm//tools/go:def.bzl
@@ -55,13 +55,6 @@ alias(
     visibility = ["//visibility:public"],
 )
 
-# Protobuf gRPC gateway compiler
-alias(
-    name = "grpc_gateway_proto_compiler",
-    actual = "@com_github_grpc_ecosystem_grpc_gateway_v2//protoc-gen-grpc-gateway:go_gen_grpc_gateway",
-    visibility = ["//visibility:public"],
-)
-
 gometalinter(
     name = "gometalinter",
     config = "//:.gometalinter.json",
@@ -172,7 +165,7 @@ STATICCHECK_ANALYZERS = [
     "sa6006",
     "sa9001",
     "sa9002",
-    #"sa9003", # Doesn't build. See https://github.com/dominikh/go-tools/pull/1483
+    "sa9003",
     "sa9004",
     "sa9005",
     "sa9006",
@@ -204,6 +197,7 @@ nogo(
         "//tools/analyzers/logruswitherror:go_default_library",
         "//tools/analyzers/maligned:go_default_library",
         "//tools/analyzers/nop:go_default_library",
+        "//tools/analyzers/nopanic:go_default_library",
         "//tools/analyzers/properpermissions:go_default_library",
         "//tools/analyzers/recursivelock:go_default_library",
         "//tools/analyzers/shadowpredecl:go_default_library",
@@ -224,6 +218,7 @@ nogo(
         "@org_golang_x_tools//go/analysis/passes/deepequalerrors:go_default_library",
         "@org_golang_x_tools//go/analysis/passes/defers:go_default_library",
         "@org_golang_x_tools//go/analysis/passes/directive:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/errorsas:go_default_library",
         # fieldalignment disabled
         #"@org_golang_x_tools//go/analysis/passes/fieldalignment:go_default_library",
         "@org_golang_x_tools//go/analysis/passes/findcall:go_default_library",

CONTRIBUTING.md

@@ -4,7 +4,10 @@ Note: The latest and most up-to-date documentation can be found on our [docs por
 
 Excited by our work and want to get involved in building out our sharding releases? Or maybe you haven't learned as much about the Ethereum protocol but are a savvy developer? 
 
-You can explore our [Open Issues](https://github.com/prysmaticlabs/prysm/issues) in-the works for our different releases. Feel free to fork our repo and start creating PR’s after assigning yourself to an issue of interest. We are always chatting on [Discord](https://discord.gg/CTYGPUJ) drop us a line there if you want to get more involved or have any questions on our implementation!
+You can explore our [Open Issues](https://github.com/OffchainLabs/prysm/issues) in-the works for our different releases. Feel free to fork our repo and start creating PR’s after assigning yourself to an issue of interest. We are always chatting on [Discord](https://discord.gg/CTYGPUJ) drop us a line there if you want to get more involved or have any questions on our implementation!
+
+> [!IMPORTANT] 
+> Please, **do not send pull requests for trivial changes**, such as typos, these will be rejected. These types of pull requests incur a cost to reviewers and do not provide much value to the project. If you are unsure, please open an issue first to discuss the change.
 
 ## Contribution Steps
 
@@ -12,15 +15,15 @@ You can explore our [Open Issues](https://github.com/prysmaticlabs/prysm/issues)
 
 **2. Fork the Prysm repo.**
 
-Sign in to your GitHub account or create a new account if you do not have one already. Then navigate your browser to https://github.com/prysmaticlabs/prysm/. In the upper right hand corner of the page, click “fork”. This will create a copy of the Prysm repo in your account.
+Sign in to your GitHub account or create a new account if you do not have one already. Then navigate your browser to https://github.com/OffchainLabs/prysm/. In the upper right hand corner of the page, click “fork”. This will create a copy of the Prysm repo in your account.
 
 **3. Create a local clone of Prysm.**
 
 ```
-$ mkdir -p $GOPATH/src/github.com/prysmaticlabs
-$ cd $GOPATH/src/github.com/prysmaticlabs
-$ git clone https://github.com/prysmaticlabs/prysm.git
-$ cd $GOPATH/src/github.com/prysmaticlabs/prysm
+$ mkdir -p $GOPATH/src/github.com/OffchainLabs
+$ cd $GOPATH/src/github.com/OffchainLabs
+$ git clone https://github.com/OffchainLabs/prysm.git
+$ cd $GOPATH/src/github.com/OffchainLabs/prysm
 ```
 
 **4. Link your local clone to the fork on your GitHub repo.**
@@ -32,13 +35,13 @@ $ git remote add myprysmrepo https://github.com/<your_github_user_name>/prysm.gi
 **5. Link your local clone to the Prysmatic Labs repo so that you can easily fetch future changes to the Prysmatic Labs repo.**
 
 ```
-$ git remote add prysm https://github.com/prysmaticlabs/prysm.git
+$ git remote add prysm https://github.com/OffchainLabs/prysm.git
 $ git remote -v (you should see myrepo and prysm in the list of remotes)
 ```
 
 **6. Find an issue to work on.**
 
-Check out open issues at https://github.com/prysmaticlabs/prysm/issues and pick one. Leave a comment to let the development team know that you would like to work on it. Or examine the code for areas that can be improved and leave a comment to the development team to ask if they would like you to work on it.
+Check out open issues at https://github.com/OffchainLabs/prysm/issues and pick one. Leave a comment to let the development team know that you would like to work on it. Or examine the code for areas that can be improved and leave a comment to the development team to ask if they would like you to work on it.
 
 **7. Create a local branch with a name that clearly identifies what you will be working on.**
 
@@ -120,15 +123,19 @@ $ git push myrepo feature-in-progress-branch
 
 Navigate to your fork of the repo on GitHub. On the upper left where the current branch is listed, change the branch to your feature-in-progress-branch. Open the files that you have worked on and check to make sure they include your changes.
 
-**16. Create a pull request.**
+**16. Add an entry to CHANGELOG.md.**
 
-Navigate your browser to https://github.com/prysmaticlabs/prysm and click on the new pull request button. In the “base” box on the left, leave the default selection “base master”, the branch that you want your changes to be applied to. In the “compare” box on the right, select feature-in-progress-branch, the branch containing the changes you want to apply. You will then be asked to answer a few questions about your pull request. After you complete the questionnaire, the pull request will appear in the list of pull requests at https://github.com/prysmaticlabs/prysm/pulls.
+All PRs must must include a changelog fragment file in the `changelog` directory. If your change is not user-facing or should not be mentioned in the changelog for some other reason, you may use the `Ignored` changelog section in your fragment's header to satisfy this requirement without altering the final release changelog. See the [Maintaining CHANGELOG.md](#maintaining-changelogmd) section for more information.
 
-**17. Respond to comments by Core Contributors.**
+**17. Create a pull request.**
+
+Navigate your browser to https://github.com/OffchainLabs/prysm and click on the new pull request button. In the “base” box on the left, leave the default selection “base develop”, the branch that you want your changes to be applied to. In the “compare” box on the right, select feature-in-progress-branch, the branch containing the changes you want to apply. You will then be asked to answer a few questions about your pull request. After you complete the questionnaire, the pull request will appear in the list of pull requests at https://github.com/OffchainLabs/prysm/pulls. Ensure that you have added an entry to CHANGELOG.md if your PR is a user-facing change. See the [Maintaining CHANGELOG.md](#maintaining-changelogmd) section for more information.
+
+**18. Respond to comments by Core Contributors.**
 
 Core Contributors may ask questions and request that you make edits. If you set notifications at the top of the page to “not watching,” you will still be notified by email whenever someone comments on the page of a pull request you have created. If you are asked to modify your pull request, repeat steps 8 through 15, then leave a comment to notify the Core Contributors that the pull request is ready for further review.
 
-**18. If the number of commits becomes excessive, you may be asked to squash your commits.**
+**19. If the number of commits becomes excessive, you may be asked to squash your commits.**
 
  You can do this with an interactive rebase. Start by running the following command to determine the commit that is the base of your branch...
 
@@ -136,7 +143,7 @@ Core Contributors may ask questions and request that you make edits. If you set
 $ git merge-base feature-in-progress-branch prysm/master
 ```
 
-**19. The previous command will return a commit-hash that you should use in the following command.**
+**20. The previous command will return a commit-hash that you should use in the following command.**
 
 ```
 $ git rebase -i commit-hash
@@ -160,13 +167,24 @@ squash  hash 	add a feature
 
 Save and close the file, then a commit command will appear in the terminal that squashes the smaller commits into one. Check to be sure the commit message accurately reflects your changes and then hit enter to execute it.
 
-**20. Update your pull request with the following command.**
+**21. Update your pull request with the following command.**
 
 ```
 $ git push myrepo feature-in-progress-branch -f
 ```
 
-**21.  Finally, again leave a comment to the Core Contributors on the pull request to let them know that the pull request has been updated.**
+**22.  Finally, again leave a comment to the Core Contributors on the pull request to let them know that the pull request has been updated.**
+
+## Maintaining CHANGELOG.md
+
+This project follows the changelog guidelines from [keepachangelog.com](https://keepachangelog.com/en/1.1.0/). In order to minimize conflicts and workflow headaches, we chose to implement a changelog management
+strategy that uses changelog "fragment" files, managed by our changelog management tool called `unclog`. Each PR must include a new changelog fragment file in the `changelog` directory, as specified by unclog's
+[README.md](https://github.com/OffchainLabs/unclog?tab=readme-ov-file#what-is-a-changelog-fragment). As the `unclog` README suggests in the [Best Practices](https://github.com/OffchainLabs/unclog?tab=readme-ov-file#best-practices) section, 
+the standard naming convention for your PR's fragment file, to avoid conflicting with another fragment file, is `changelog/<github user name>_<PR branch name>.md`.
+
+### Releasing
+
+When a new release is made, the "Unreleased" section should be moved to a new section with the release version and the current date. Then a new "Unreleased" section is made at the top of the file with the categories listed above.
 
 ## Contributor Responsibilities
 

DEPENDENCIES.md

@@ -2,7 +2,7 @@
 
 Prysm is go project with many complicated dependencies, including some c++ based libraries. There
 are two parts to Prysm's dependency management. Go modules and bazel managed dependencies. Be sure 
-to read [Why Bazel?](https://github.com/prysmaticlabs/documentation/issues/138) to fully
+to read [Why Bazel?](https://github.com/OffchainLabs/documentation/issues/138) to fully
 understand the reasoning behind an additional layer of build tooling via Bazel rather than a pure
 "go build" project.
 
@@ -55,12 +55,12 @@ bazel build //beacon-chain --config=release
 ## Adding / updating dependencies
 
 1. Add your dependency as you would with go modules. I.e. `go get ...`
-1. Run `bazel run //:gazelle -- update-repos -from_file=go.mod` to update the bazel managed dependencies.
+1. Run `bazel run //:gazelle -- update-repos -from_file=go.mod -to_macro=deps.bzl%prysm_deps -prune=true` to update the bazel managed dependencies.
 
 Example:
 
 ```bash
-go get github.com/prysmaticlabs/example@v1.2.3
+go get github.com/OffchainLabs/example@v1.2.3
 bazel run //:gazelle -- update-repos -from_file=go.mod -to_macro=deps.bzl%prysm_deps -prune=true
 ```
 

INTEROP.md

@@ -2,18 +2,21 @@
 
 This README details how to setup Prysm for interop testing for usage with other Ethereum consensus clients.
 
+> [!IMPORTANT]  
+> This guide is likely to be outdated. The Prysm team does not have capacity to troubleshoot
+> outdated interop guides or instructions. If you experience issues with this guide, please file an
+> issue for visibility and propose fixes, if possible.
+
 ## Installation & Setup
 
 1. Install [Bazel](https://docs.bazel.build/versions/master/install.html) **(Recommended)**
-2. `git clone https://github.com/prysmaticlabs/prysm && cd prysm`
-3. `bazel build //...`
+2. `git clone https://github.com/OffchainLabs/prysm && cd prysm`
+3. `bazel build //cmd/...`
 
 ## Starting from Genesis
 
-Prysm supports a few ways to quickly launch a beacon node from basic configurations:
-
-- `NumValidators + GenesisTime`: Launches a beacon node by deterministically generating a state from a num-validators flag along with a genesis time **(Recommended)**
-- `SSZ Genesis`: Launches a beacon node  from a .ssz file containing a SSZ-encoded, genesis beacon state
+Prysm can be started from a built-in mainnet genesis state, or started with a provided genesis state by
+using the `--genesis-state` flag and providing a path to the genesis.ssz file.
 
 ## Generating a Genesis State
 
@@ -21,21 +24,34 @@ To setup the necessary files for these quick starts, Prysm provides a tool to ge
 a deterministically generated set of validator private keys following the official interop YAML format 
 [here](https://github.com/ethereum/eth2.0-pm/blob/master/interop/mocked_start).
 
-You can use `bazel run //tools/genesis-state-gen` to create a deterministic genesis state for interop.
+You can use `prysmctl` to create a deterministic genesis state for interop.
 
-### Usage
-
-- **--genesis-time** uint: Unix timestamp used as the genesis time in the generated genesis state (defaults to now)
-- **--num-validators** int: Number of validators to deterministically include in the generated genesis state
-- **--output-ssz** string: Output filename of the SSZ marshaling of the generated genesis state
-- **--config-name=interop** string: name of the beacon chain config to use when generating the state. ex mainnet|minimal|interop
-
-The example below creates 64 validator keys, instantiates a genesis state with those 64 validators and with genesis unix timestamp 1567542540,
-and finally writes a ssz encoded output to ~/Desktop/genesis.ssz. This file can be used to kickstart the beacon chain in the next section. When using the `--interop-*` flags, the beacon node will assume the `interop` config should be used, unless a different config is specified on the command line.
+```sh
+# Download (or create) a chain config file.
+curl https://raw.githubusercontent.com/ethereum/consensus-specs/refs/heads/dev/configs/minimal.yaml -o /tmp/minimal.yaml
 
+# Run prysmctl to generate genesis with a 2 minute genesis delay and 256 validators. 
+bazel run //cmd/prysmctl --config=minimal -- \
+  testnet generate-genesis \
+  --genesis-time-delay=120 \
+  --num-validators=256 \
+  --output-ssz=/tmp/genesis.ssz \
+  --chain-config-file=/tmp/minimal.yaml
 ```
-bazel run //tools/genesis-state-gen -- --config-name interop --output-ssz ~/Desktop/genesis.ssz --num-validators 64 --genesis-time 1567542540
-```
+
+The flags are explained below:
+- `bazel run //cmd/prysmctl` is the bazel command to compile and run prysmctl.
+- `--config=minimal` is a bazel build time configuration flag to compile Prysm with minimal state constants.
+- `--` is an argument divider to tell bazel that everything after this divider should be passed as arguments to prysmctl. Without this divider, it isn't clear to bazel if the arguments are meant to be build time arguments or runtime arguments so the operation complains and fails to build without this divider.
+- `testnet` is the primary command argument for prysmctl.
+- `generate-genesis` is the subcommand to `testnet` in prysmctl.
+- `--genesis-time-delay` uint: The number of seconds in the future to define genesis. Example: a value of 60 will set the genesis time to 1 minute in the future. This should be sufficiently large enough to allow for you to start the beacon node before the genesis time. 
+- `--num-validators` int: Number of validators to deterministically include in the generated genesis state
+- `--output-ssz` string: Output filename of the SSZ marshaling of the generated genesis state
+- `--chain-config-file` string: Filepath to a chain config yaml file.
+
+Note: This guide saves items to the `/tmp/` directory which will not persist if your machine is
+restarted. Consider tweaking the arguments if persistence is needed.
 
 ## Launching a Beacon Node + Validator Client
 
@@ -44,45 +60,33 @@ bazel run //tools/genesis-state-gen -- --config-name interop --output-ssz ~/Desk
 Open up two terminal windows, run:
 
 ```
-bazel run //beacon-chain -- \
---bootstrap-node= \
---deposit-contract 0x8A04d14125D0FDCDc742F4A05C051De07232EDa4 \
---datadir=/tmp/beacon-chain-interop \
---force-clear-db \
---min-sync-peers=0 \
---interop-num-validators 64 \
---interop-eth1data-votes
+bazel run //cmd/beacon-chain --config=minimal -- \
+  --minimal-config \
+  --bootstrap-node= \
+  --deposit-contract 0x8A04d14125D0FDCDc742F4A05C051De07232EDa4 \
+  --datadir=/tmp/beacon-chain-minimal-devnet \
+  --force-clear-db \
+  --min-sync-peers=0 \
+  --genesis-state=/tmp/genesis.ssz \
+  --chain-config-file=/tmp/minimal.yaml
 ```
 
-This will deterministically generate a beacon genesis state and start
-the system with 64 validators and the genesis time set to the current unix timestamp.
-Wait a bit until your beacon chain starts, and in the other window:
+This will start the system with 256 validators. The flags used can be explained as such:
+
+- `bazel run //cmd/beacon-chain --config=minimal` builds and runs the beacon node in minimal build configuration.
+- `--` is a flag divider to distinguish between bazel flags and flags that should be passed to the application. All flags and arguments after this divider are passed to the beacon chain.
+- `--minimal-config` tells the beacon node to use minimal network configuration. This is different from the compile time state configuration flag `--config=minimal` and both are required.
+- `--bootstrap-node=` disables the default bootstrap nodes. This prevents the client from attempting to peer with mainnet nodes.
+- `--datadir=/tmp/beacon-chain-minimal-devnet` sets the data directory in a temporary location. Change this to your preferred destination.
+- `--force-clear-db` will delete the beaconchain.db file without confirming with the user. This is helpful for iteratively running local devnets without changing the datadir, but less helpful for one off runs where there was no database in the data directory.
+- `--min-sync-peers=0` allows the beacon node to skip initial sync without peers. This is essential because Prysm expects at least a few peers to start the blockchain.
+- `--genesis-state=/tmp/genesis.ssz` defines the path to the generated genesis ssz file. The beacon node will use this as the initial genesis state.
+- `--chain-config-file=/tmp/minimal.yaml` defines the path to the yaml file with the chain configuration.
+
+As soon as the beacon node has started, start the validator in the other terminal window. 
 
 ```
-bazel run //validator -- --keymanager=interop --keymanageropts='{"keys":64}'
+bazel run //cmd/validator --config=minimal -- --datadir=/tmp/validator --interop-num-validators=256 --minimal-config --suggested-fee-recipient=0x8A04d14125D0FDCDc742F4A05C051De07232EDa4
 ```
 
-This will launch and kickstart the system with your 64 validators performing their duties accordingly.
-
-### Launching from `genesis.ssz`
-
-Assuming you generated a `genesis.ssz` file with 64 validators, open up two terminal windows, run:
-
-```
- bazel run //beacon-chain -- \
---bootstrap-node= \
---deposit-contract 0x8A04d14125D0FDCDc742F4A05C051De07232EDa4 \
---datadir=/tmp/beacon-chain-interop \
---force-clear-db \
---min-sync-peers=0 \
---interop-genesis-state /path/to/genesis.ssz \
---interop-eth1data-votes
-```
-
-Wait a bit until your beacon chain starts, and in the other window:
-
-```
-bazel run //validator -- --keymanager=interop --keymanageropts='{"keys":64}'
-```
-
-This will launch and kickstart the system with your 64 validators performing their duties accordingly.
+This will launch and kickstart the system with your 256 validators performing their duties accordingly.

README.md

@@ -1,37 +1,68 @@
-# Prysm: An Ethereum Consensus Implementation Written in Go
+<h1 align="left">Prysm: An Ethereum Consensus Implementation Written in Go</h1>
 
+<div align="left">
+  
 [![Build status](https://badge.buildkite.com/b555891daf3614bae4284dcf365b2340cefc0089839526f096.svg?branch=master)](https://buildkite.com/prysmatic-labs/prysm)
-[![Go Report Card](https://goreportcard.com/badge/github.com/prysmaticlabs/prysm)](https://goreportcard.com/report/github.com/prysmaticlabs/prysm)
+[![Go Report Card](https://goreportcard.com/badge/github.com/OffchainLabs/prysm)](https://goreportcard.com/report/github.com/OffchainLabs/prysm)
 [![Consensus_Spec_Version 1.4.0](https://img.shields.io/badge/Consensus%20Spec%20Version-v1.4.0-blue.svg)](https://github.com/ethereum/consensus-specs/tree/v1.4.0)
 [![Execution_API_Version 1.0.0-beta.2](https://img.shields.io/badge/Execution%20API%20Version-v1.0.0.beta.2-blue.svg)](https://github.com/ethereum/execution-apis/tree/v1.0.0-beta.2/src/engine)
-[![Discord](https://user-images.githubusercontent.com/7288322/34471967-1df7808a-efbb-11e7-9088-ed0b04151291.png)](https://discord.gg/prysmaticlabs)
-[![GitPOAP Badge](https://public-api.gitpoap.io/v1/repo/prysmaticlabs/prysm/badge)](https://www.gitpoap.io/gh/prysmaticlabs/prysm)
+[![Discord](https://user-images.githubusercontent.com/7288322/34471967-1df7808a-efbb-11e7-9088-ed0b04151291.png)](https://discord.gg/OffchainLabs)
+[![GitPOAP Badge](https://public-api.gitpoap.io/v1/repo/OffchainLabs/prysm/badge)](https://www.gitpoap.io/gh/OffchainLabs/prysm)
 
-This is the core repository for Prysm, a [Golang](https://golang.org/) implementation of the [Ethereum Consensus](https://ethereum.org/en/developers/docs/consensus-mechanisms/#proof-of-stake) [specification](https://github.com/ethereum/consensus-specs), developed by [Offchain Labs](https://www.offchainlabs.com). See the [Changelog](https://github.com/prysmaticlabs/prysm/releases) for details of the latest releases and upcoming breaking changes.
+</div>
 
-### Getting Started
+---
 
-A detailed set of installation and usage instructions as well as breakdowns of each individual component are available in the [official documentation portal](https://docs.prylabs.network). If you still have questions, feel free to stop by our [Discord](https://discord.gg/prysmaticlabs).
+## 📖 Overview
 
-### Staking on Mainnet
+This is the core repository for Prysm, a [Golang](https://golang.org/) implementation of the [Ethereum Consensus](https://ethereum.org/en/developers/docs/consensus-mechanisms/#proof-of-stake) [specification](https://github.com/ethereum/consensus-specs), developed by [Offchain Labs](https://www.offchainlabs.com).
 
-To participate in staking, you can join the [official eth2 launchpad](https://launchpad.ethereum.org). The launchpad is the only recommended way to become a validator on mainnet. You can explore validator rewards/penalties via Bitfly's block explorer: [beaconcha.in](https://beaconcha.in), and follow the latest blocks added to the chain on [beaconscan](https://beaconscan.com).
+See the [Changelog](https://github.com/OffchainLabs/prysm/releases) for details of the latest releases and upcoming breaking changes.
 
+---
+
+## 🚀 Getting Started
+
+A detailed set of installation and usage instructions as well as breakdowns of each individual component are available in the **[official documentation portal](https://docs.prylabs.network)**.
+
+💬 **Need help?** Join our **[Discord Community](https://discord.gg/OffchainLabs)** for support.
+
+---
+
+## 🏆 Staking on Mainnet
+
+To participate in staking, you can join the **[official Ethereum launchpad](https://launchpad.ethereum.org)**. The launchpad is the **only recommended** way to become a validator on mainnet.
+
+🔍 Explore validator rewards/penalties:
+
+- **[beaconcha.in](https://beaconcha.in)**
+- **[beaconscan](https://beaconscan.com)**
+
+---
+
+## 🤝 Contributing
+
+### 🔥 Branches
 
-## Contributing
-### Branches
 Prysm maintains two permanent branches:
 
-* [master](https://github.com/prysmaticlabs/prysm/tree/master): This points to the latest stable release. It is ideal for most users.
-* [develop](https://github.com/prysmaticlabs/prysm/tree/develop): This is used for development, it contains the latest PRs. Developers should base their PRs on this branch.
+- **[`master`](https://github.com/OffchainLabs/prysm/tree/master)** - This points to the latest stable release. It is ideal for most users.
+- **[`develop`](https://github.com/OffchainLabs/prysm/tree/develop)** - This is used for development and contains the latest PRs. Developers should base their PRs on this branch.
 
-### Guide
-Want to get involved? Check out our [Contribution Guide](https://docs.prylabs.network/docs/contribute/contribution-guidelines/) to learn more!
+### 🛠 Contribution Guide
 
-## License
+Want to get involved? Check out our **[Contribution Guide](https://docs.prylabs.network/docs/contribute/contribution-guidelines/)** to learn more!
 
-[GNU General Public License v3.0](https://www.gnu.org/licenses/gpl-3.0.en.html)
+---
 
-## Legal Disclaimer
+## 📜 License
 
-[Terms of Use](/TERMS_OF_SERVICE.md)
+[![License: GPL v3](https://img.shields.io/badge/License-GPLv3-blue.svg)](https://www.gnu.org/licenses/gpl-3.0.en.html)  
+
+This project is licensed under the **GNU General Public License v3.0**.
+
+---
+
+## ⚖️ Legal Disclaimer
+
+📜 [Terms of Use](/TERMS_OF_SERVICE.md)

SECURITY.md

@@ -2,10 +2,10 @@
 
 ## Supported Versions
 
-[Releases](https://github.com/prysmaticlabs/prysm/releases/) contains all available releases. We recommend using the [most recently released version](https://github.com/prysmaticlabs/prysm/releases/latest).
+[Releases](https://github.com/OffchainLabs/prysm/releases/) contains all available releases. We recommend using the [most recently released version](https://github.com/OffchainLabs/prysm/releases/latest).
 
 ## Reporting a Vulnerability
 
-Please see our signed [security.txt](https://github.com/prysmaticlabs/prysm/blob/develop/.well-known/security.txt) for preferred encryption and reporting destination.
+Please see our signed [security.txt](https://github.com/OffchainLabs/prysm/blob/develop/.well-known/security.txt) for preferred encryption and reporting destination.
 
 **Please do not file a public ticket** mentioning the vulnerability, as doing so could increase the likelihood of the vulnerability being used before a fix has been created, released and installed on the network.

WORKSPACE

@@ -1,7 +1,7 @@
 workspace(name = "prysm")
 
-load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 http_archive(
     name = "rules_pkg",
@@ -16,6 +16,32 @@ load("@rules_pkg//:deps.bzl", "rules_pkg_dependencies")
 
 rules_pkg_dependencies()
 
+http_archive(
+    name = "toolchains_protoc",
+    sha256 = "abb1540f8a9e045422730670ebb2f25b41fa56ca5a7cf795175a110a0a68f4ad",
+    strip_prefix = "toolchains_protoc-0.3.6",
+    url = "https://github.com/aspect-build/toolchains_protoc/releases/download/v0.3.6/toolchains_protoc-v0.3.6.tar.gz",
+)
+
+load("@toolchains_protoc//protoc:repositories.bzl", "rules_protoc_dependencies")
+
+rules_protoc_dependencies()
+
+load("@rules_proto//proto:repositories.bzl", "rules_proto_dependencies")
+
+rules_proto_dependencies()
+
+load("@bazel_features//:deps.bzl", "bazel_features_deps")
+
+bazel_features_deps()
+
+load("@toolchains_protoc//protoc:toolchain.bzl", "protoc_toolchains")
+
+protoc_toolchains(
+    name = "protoc_toolchains",
+    version = "v25.3",
+)
+
 HERMETIC_CC_TOOLCHAIN_VERSION = "v3.0.1"
 
 http_archive(
@@ -29,23 +55,7 @@ http_archive(
 
 load("@hermetic_cc_toolchain//toolchain:defs.bzl", zig_toolchains = "toolchains")
 
-# Temporarily use a nightly build until 0.12.0 is released.
-# See: https://github.com/prysmaticlabs/prysm/issues/13130
-zig_toolchains(
-    host_platform_sha256 = {
-        "linux-aarch64": "45afb8e32adde825165f4f293fcea9ecea503f7f9ec0e9bf4435afe70e67fb70",
-        "linux-x86_64": "f136c6a8a0f6adcb057d73615fbcd6f88281b3593f7008d5f7ed514ff925c02e",
-        "macos-aarch64": "05d995853c05243151deff47b60bdc2674f1e794a939eaeca0f42312da031cee",
-        "macos-x86_64": "721754ba5a50f31e8a1f0e1a74cace26f8246576878ac4a8591b0ee7b6db1fc1",
-        "windows-x86_64": "93f5248b2ea8c5ee8175e15b1384e133edc1cd49870b3ea259062a2e04164343",
-    },
-    url_formats = [
-        "https://ziglang.org/builds/zig-{host_platform}-{version}.{_ext}",
-        "https://mirror.bazel.build/ziglang.org/builds/zig-{host_platform}-{version}.{_ext}",
-        "https://prysmaticlabs.com/mirror/ziglang.org/builds/zig-{host_platform}-{version}.{_ext}",
-    ],
-    version = "0.12.0-dev.1349+fa022d1ec",
-)
+zig_toolchains()
 
 # Register zig sdk toolchains with support for Ubuntu 20.04 (Focal Fossa) which has an EOL date of April, 2025.
 # For ubuntu glibc support, see https://launchpad.net/ubuntu/+source/glibc
@@ -117,9 +127,9 @@ http_archive(
 
 http_archive(
     name = "aspect_bazel_lib",
-    sha256 = "f5ea76682b209cc0bd90d0f5a3b26d2f7a6a2885f0c5f615e72913f4805dbb0d",
-    strip_prefix = "bazel-lib-2.5.0",
-    url = "https://github.com/aspect-build/bazel-lib/releases/download/v2.5.0/bazel-lib-v2.5.0.tar.gz",
+    sha256 = "a272d79bb0ac6b6965aa199b1f84333413452e87f043b53eca7f347a23a478e8",
+    strip_prefix = "bazel-lib-2.9.3",
+    url = "https://github.com/bazel-contrib/bazel-lib/releases/download/v2.9.3/bazel-lib-v2.9.3.tar.gz",
 )
 
 load("@aspect_bazel_lib//lib:repositories.bzl", "aspect_bazel_lib_dependencies", "aspect_bazel_lib_register_toolchains")
@@ -148,15 +158,15 @@ oci_register_toolchains(
 
 http_archive(
     name = "io_bazel_rules_go",
+    integrity = "sha256-JD8o94crTb2DFiJJR8nMAGdBAW95zIENB4cbI+JnrI4=",
     patch_args = ["-p1"],
     patches = [
         # Expose internals of go_test for custom build transitions.
         "//third_party:io_bazel_rules_go_test.patch",
     ],
-    sha256 = "80a98277ad1311dacd837f9b16db62887702e9f1d1c4c9f796d0121a46c8e184",
+    strip_prefix = "rules_go-cf3c3af34bd869b864f5f2b98e2f41c2b220d6c9",
     urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.46.0/rules_go-v0.46.0.zip",
-        "https://github.com/bazelbuild/rules_go/releases/download/v0.46.0/rules_go-v0.46.0.zip",
+        "https://github.com/bazel-contrib/rules_go/archive/cf3c3af34bd869b864f5f2b98e2f41c2b220d6c9.tar.gz",
     ],
 )
 
@@ -181,7 +191,7 @@ load("@rules_oci//oci:pull.bzl", "oci_pull")
 oci_pull(
     name = "linux_debian11_multiarch_base",  # Debian bullseye
     digest = "sha256:b82f113425c5b5c714151aaacd8039bc141821cdcd3c65202d42bdf9c43ae60b",  # 2023-12-12
-    image = "gcr.io/distroless/cc-debian11",
+    image = "gcr.io/prysmaticlabs/distroless/cc-debian11",
     platforms = [
         "linux/amd64",
         "linux/arm64/v8",
@@ -198,7 +208,7 @@ load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_depe
 go_rules_dependencies()
 
 go_register_toolchains(
-    go_version = "1.21.8",
+    go_version = "1.24.0",
     nogo = "@//:nogo",
 )
 
@@ -243,7 +253,7 @@ filegroup(
     url = "https://github.com/ethereum/EIPs/archive/5480440fe51742ed23342b68cf106cefd427e39d.tar.gz",
 )
 
-consensus_spec_version = "v1.4.0"
+consensus_spec_version = "v1.5.0-beta.5"
 
 bls_test_version = "v0.1.1"
 
@@ -259,7 +269,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    sha256 = "c282c0f86f23f3d2e0f71f5975769a4077e62a7e3c7382a16bd26a7e589811a0",
+    integrity = "sha256-H+Pt4z+HCVDnEBAv814yvsjR7f5l1IpumjFoTj2XnLE=",
     url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/general.tar.gz" % consensus_spec_version,
 )
 
@@ -275,7 +285,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    sha256 = "4649c35aa3b8eb0cfdc81bee7c05649f90ef36bede5b0513e1f2e8baf37d6033",
+    integrity = "sha256-Dqiwf5BG7yYyURGf+i87AIdArAyztvcgjoi2kSxrGvo=",
     url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/minimal.tar.gz" % consensus_spec_version,
 )
 
@@ -291,7 +301,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    sha256 = "c5a03f724f757456ffaabd2a899992a71d2baf45ee4db65ca3518f2b7ee928c8",
+    integrity = "sha256-xrmsFF243pzXHAjh1EQYKS9gtcwmtHK3wRZDSLlVVRk=",
     url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/mainnet.tar.gz" % consensus_spec_version,
 )
 
@@ -306,7 +316,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    sha256 = "cd1c9d97baccbdde1d2454a7dceb8c6c61192a3b581eee12ffc94969f2db8453",
+    integrity = "sha256-c+gGapqifCvFtmtxfhOwieBDO2Syxp13GECWEpWM/Ho=",
     strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
     url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )
@@ -342,36 +352,68 @@ filegroup(
     url = "https://github.com/eth-clients/eth2-networks/archive/934c948e69205dcf2deb87e4ae6cc140c335f94d.tar.gz",
 )
 
-http_archive(
-    name = "goerli_testnet",
-    build_file_content = """
-filegroup(
-    name = "configs",
-    srcs = [
-        "prater/config.yaml",
-    ],
-    visibility = ["//visibility:public"],
-)
-    """,
-    sha256 = "43fc0f55ddff7b511713e2de07aa22846a67432df997296fb4fc09cd8ed1dcdb",
-    strip_prefix = "goerli-6522ac6684693740cd4ddcc2a0662e03702aa4a1",
-    url = "https://github.com/eth-clients/goerli/archive/6522ac6684693740cd4ddcc2a0662e03702aa4a1.tar.gz",
-)
-
 http_archive(
     name = "holesky_testnet",
     build_file_content = """
 filegroup(
     name = "configs",
     srcs = [
-        "custom_config_data/config.yaml",
+        "metadata/config.yaml",
     ],
     visibility = ["//visibility:public"],
 )
 """,
-    sha256 = "5f4be6fd088683ea9db45c863b9c5a1884422449e5b59fd2d561d3ba0f73ffd9",
-    strip_prefix = "holesky-9d9aabf2d4de51334ee5fed6c79a4d55097d1a43",
-    url = "https://github.com/eth-clients/holesky/archive/9d9aabf2d4de51334ee5fed6c79a4d55097d1a43.tar.gz",  # 2024-01-22
+    integrity = "sha256-YVFFrCmjoGZ3fXMWpsCpSsYbANy1grnqYwOLKIg2SsA=",
+    strip_prefix = "holesky-32a72e21c6e53c262f27d50dd540cb654517d03a",
+    url = "https://github.com/eth-clients/holesky/archive/32a72e21c6e53c262f27d50dd540cb654517d03a.tar.gz",  # 2025-03-17
+)
+
+http_archive(
+    name = "mainnet",
+    build_file_content = """
+filegroup(
+    name = "configs",
+    srcs = [
+        "metadata/config.yaml",
+    ],
+    visibility = ["//visibility:public"],
+)
+""",
+    integrity = "sha256-NZr/gsQK9rBHRnznlPBiNzJpK8MPMrfUa3f+QYqn1+g=",
+    strip_prefix = "mainnet-978f1794eada6f85bee76e4d2d5959a5fb8e0cc5",
+    url = "https://github.com/eth-clients/mainnet/archive/978f1794eada6f85bee76e4d2d5959a5fb8e0cc5.tar.gz",
+)
+
+http_archive(
+    name = "sepolia_testnet",
+    build_file_content = """
+filegroup(
+    name = "configs",
+    srcs = [
+        "metadata/config.yaml",
+    ],
+    visibility = ["//visibility:public"],
+)
+""",
+    integrity = "sha256-b5F7Wg9LLMqGRIpP2uqb/YsSFVn2ynzlV7g/Nb1EFLk=",
+    strip_prefix = "sepolia-562d9938f08675e9ba490a1dfba21fb05843f39f",
+    url = "https://github.com/eth-clients/sepolia/archive/562d9938f08675e9ba490a1dfba21fb05843f39f.tar.gz",  # 2025-03-17
+)
+
+http_archive(
+    name = "hoodi_testnet",
+    build_file_content = """
+filegroup(
+    name = "configs",
+    srcs = [
+        "metadata/config.yaml",
+    ],
+    visibility = ["//visibility:public"],
+)
+""",
+    integrity = "sha256-dPiEWUd8QvbYGwGtIm0QtCekitVLOLsW5rpQIGzz8PU=",
+    strip_prefix = "hoodi-828c2c940e1141092bd4bb979cef547ea926d272",
+    url = "https://github.com/eth-clients/hoodi/archive/828c2c940e1141092bd4bb979cef547ea926d272.tar.gz",
 )
 
 http_archive(
@@ -419,7 +461,7 @@ gometalinter_dependencies()
 
 load("@bazel_gazelle//:deps.bzl", "gazelle_dependencies")
 
-gazelle_dependencies()
+gazelle_dependencies(go_sdk = "go_sdk")
 
 load("@com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")
 

api/BUILD.bazel

@@ -1,11 +1,24 @@
-load("@prysm//tools/go:def.bzl", "go_library")
+load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "go_default_library",
     srcs = [
         "constants.go",
         "headers.go",
+        "jwt.go",
     ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api",
+    importpath = "github.com/OffchainLabs/prysm/v6/api",
     visibility = ["//visibility:public"],
+    deps = [
+        "//crypto/rand:go_default_library",
+        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["jwt_test.go"],
+    embed = [":go_default_library"],
+    deps = ["//testing/require:go_default_library"],
 )

api/apiutil/BUILD.bazel

@@ -0,0 +1,19 @@
+load("@prysm//tools/go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["common.go"],
+    importpath = "github.com/OffchainLabs/prysm/v6/api/apiutil",
+    visibility = ["//visibility:public"],
+    deps = ["//consensus-types/primitives:go_default_library"],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["common_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "//consensus-types/primitives:go_default_library",
+        "//testing/assert:go_default_library",
+    ],
+)

api/apiutil/common.go

@@ -0,0 +1,23 @@
+package apiutil
+
+import (
+	"fmt"
+	neturl "net/url"
+	"strconv"
+
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+)
+
+// Uint64ToString is a util function that will convert uints to string
+func Uint64ToString[T uint64 | primitives.Slot | primitives.ValidatorIndex | primitives.CommitteeIndex | primitives.Epoch](val T) string {
+	return strconv.FormatUint(uint64(val), 10)
+}
+
+// BuildURL is a util function that assists with adding query parameters to the url
+func BuildURL(path string, queryParams ...neturl.Values) string {
+	if len(queryParams) == 0 {
+		return path
+	}
+
+	return fmt.Sprintf("%s?%s", path, queryParams[0].Encode())
+}

api/apiutil/common_test.go

@@ -0,0 +1,37 @@
+package apiutil
+
+import (
+	"net/url"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
+)
+
+func TestBeaconApiHelpers_TestUint64ToString(t *testing.T) {
+	const expectedResult = "1234"
+	const val = uint64(1234)
+
+	assert.Equal(t, expectedResult, Uint64ToString(val))
+	assert.Equal(t, expectedResult, Uint64ToString(primitives.Slot(val)))
+	assert.Equal(t, expectedResult, Uint64ToString(primitives.ValidatorIndex(val)))
+	assert.Equal(t, expectedResult, Uint64ToString(primitives.CommitteeIndex(val)))
+	assert.Equal(t, expectedResult, Uint64ToString(primitives.Epoch(val)))
+}
+
+func TestBuildURL_NoParams(t *testing.T) {
+	wanted := "/aaa/bbb/ccc"
+	actual := BuildURL("/aaa/bbb/ccc")
+	assert.Equal(t, wanted, actual)
+}
+
+func TestBuildURL_WithParams(t *testing.T) {
+	params := url.Values{}
+	params.Add("xxxx", "1")
+	params.Add("yyyy", "2")
+	params.Add("zzzz", "3")
+
+	wanted := "/aaa/bbb/ccc?xxxx=1&yyyy=2&zzzz=3"
+	actual := BuildURL("/aaa/bbb/ccc", params)
+	assert.Equal(t, wanted, actual)
+}

api/client/BUILD.bazel

@@ -7,7 +7,7 @@ go_library(
         "errors.go",
         "options.go",
     ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client",
+    importpath = "github.com/OffchainLabs/prysm/v6/api/client",
     visibility = ["//visibility:public"],
     deps = ["@com_github_pkg_errors//:go_default_library"],
 )

api/client/beacon/BUILD.bazel

@@ -3,61 +3,33 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = [
-        "checkpoint.go",
         "client.go",
         "doc.go",
-        "health.go",
         "log.go",
+        "template.go",
     ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/beacon",
+    importpath = "github.com/OffchainLabs/prysm/v6/api/client/beacon",
     visibility = ["//visibility:public"],
     deps = [
         "//api/client:go_default_library",
-        "//api/client/beacon/iface:go_default_library",
         "//api/server:go_default_library",
         "//api/server/structs:go_default_library",
-        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//consensus-types/interfaces:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//encoding/bytesutil:go_default_library",
-        "//encoding/ssz/detect:go_default_library",
-        "//io/file:go_default_library",
         "//network/forks:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
-        "//runtime/version:go_default_library",
-        "//time/slots:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
-        "@org_golang_x_mod//semver:go_default_library",
     ],
 )
 
 go_test(
     name = "go_default_test",
-    srcs = [
-        "checkpoint_test.go",
-        "client_test.go",
-        "health_test.go",
-    ],
+    srcs = ["client_test.go"],
     embed = [":go_default_library"],
     deps = [
         "//api/client:go_default_library",
-        "//api/client/beacon/testing:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//config/params:go_default_library",
-        "//consensus-types/blocks:go_default_library",
-        "//consensus-types/blocks/testing:go_default_library",
-        "//consensus-types/primitives:go_default_library",
-        "//encoding/ssz/detect:go_default_library",
-        "//network/forks:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//runtime/version:go_default_library",
         "//testing/require:go_default_library",
-        "//testing/util:go_default_library",
-        "//time/slots:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
-        "@org_uber_go_mock//gomock:go_default_library",
     ],
 )

api/client/beacon/checkpoint.go

@@ -1,276 +0,0 @@
-package beacon
-
-import (
-	"context"
-	"fmt"
-	"path"
-
-	"github.com/ethereum/go-ethereum/common/hexutil"
-	"github.com/pkg/errors"
-	base "github.com/prysmaticlabs/prysm/v5/api/client"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	"github.com/prysmaticlabs/prysm/v5/encoding/ssz/detect"
-	"github.com/prysmaticlabs/prysm/v5/io/file"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
-	"github.com/prysmaticlabs/prysm/v5/time/slots"
-	"github.com/sirupsen/logrus"
-	"golang.org/x/mod/semver"
-)
-
-var errCheckpointBlockMismatch = errors.New("mismatch between checkpoint sync state and block")
-
-// OriginData represents the BeaconState and ReadOnlySignedBeaconBlock necessary to start an empty Beacon Node
-// using Checkpoint Sync.
-type OriginData struct {
-	sb []byte
-	bb []byte
-	st state.BeaconState
-	b  interfaces.ReadOnlySignedBeaconBlock
-	vu *detect.VersionedUnmarshaler
-	br [32]byte
-	sr [32]byte
-}
-
-// SaveBlock saves the downloaded block to a unique file in the given path.
-// For readability and collision avoidance, the file name includes: type, config name, slot and root
-func (o *OriginData) SaveBlock(dir string) (string, error) {
-	blockPath := path.Join(dir, fname("block", o.vu, o.b.Block().Slot(), o.br))
-	return blockPath, file.WriteFile(blockPath, o.BlockBytes())
-}
-
-// SaveState saves the downloaded state to a unique file in the given path.
-// For readability and collision avoidance, the file name includes: type, config name, slot and root
-func (o *OriginData) SaveState(dir string) (string, error) {
-	statePath := path.Join(dir, fname("state", o.vu, o.st.Slot(), o.sr))
-	return statePath, file.WriteFile(statePath, o.StateBytes())
-}
-
-// StateBytes returns the ssz-encoded bytes of the downloaded BeaconState value.
-func (o *OriginData) StateBytes() []byte {
-	return o.sb
-}
-
-// BlockBytes returns the ssz-encoded bytes of the downloaded ReadOnlySignedBeaconBlock value.
-func (o *OriginData) BlockBytes() []byte {
-	return o.bb
-}
-
-func fname(prefix string, vu *detect.VersionedUnmarshaler, slot primitives.Slot, root [32]byte) string {
-	return fmt.Sprintf("%s_%s_%s_%d-%#x.ssz", prefix, vu.Config.ConfigName, version.String(vu.Fork), slot, root)
-}
-
-// DownloadFinalizedData downloads the most recently finalized state, and the block most recently applied to that state.
-// This pair can be used to initialize a new beacon node via checkpoint sync.
-func DownloadFinalizedData(ctx context.Context, client *Client) (*OriginData, error) {
-	sb, err := client.GetState(ctx, IdFinalized)
-	if err != nil {
-		return nil, err
-	}
-	vu, err := detect.FromState(sb)
-	if err != nil {
-		return nil, errors.Wrap(err, "error detecting chain config for finalized state")
-	}
-
-	log.WithFields(logrus.Fields{
-		"name": vu.Config.ConfigName,
-		"fork": version.String(vu.Fork),
-	}).Info("Detected supported config in remote finalized state")
-
-	s, err := vu.UnmarshalBeaconState(sb)
-	if err != nil {
-		return nil, errors.Wrap(err, "error unmarshaling finalized state to correct version")
-	}
-
-	slot := s.LatestBlockHeader().Slot
-	bb, err := client.GetBlock(ctx, IdFromSlot(slot))
-	if err != nil {
-		return nil, errors.Wrapf(err, "error requesting block by slot = %d", slot)
-	}
-	b, err := vu.UnmarshalBeaconBlock(bb)
-	if err != nil {
-		return nil, errors.Wrap(err, "unable to unmarshal block to a supported type using the detected fork schedule")
-	}
-	br, err := b.Block().HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "error computing hash_tree_root of retrieved block")
-	}
-	bodyRoot, err := b.Block().Body().HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "error computing hash_tree_root of retrieved block body")
-	}
-
-	sbr := bytesutil.ToBytes32(s.LatestBlockHeader().BodyRoot)
-	if sbr != bodyRoot {
-		return nil, errors.Wrapf(errCheckpointBlockMismatch, "state body root = %#x, block body root = %#x", sbr, bodyRoot)
-	}
-	sr, err := s.HashTreeRoot(ctx)
-	if err != nil {
-		return nil, errors.Wrapf(err, "failed to compute htr for finalized state at slot=%d", s.Slot())
-	}
-
-	log.
-		WithField("blockSlot", b.Block().Slot()).
-		WithField("stateSlot", s.Slot()).
-		WithField("stateRoot", hexutil.Encode(sr[:])).
-		WithField("blockRoot", hexutil.Encode(br[:])).
-		Info("Downloaded checkpoint sync state and block.")
-	return &OriginData{
-		st: s,
-		b:  b,
-		sb: sb,
-		bb: bb,
-		vu: vu,
-		br: br,
-		sr: sr,
-	}, nil
-}
-
-// WeakSubjectivityData represents the state root, block root and epoch of the BeaconState + ReadOnlySignedBeaconBlock
-// that falls at the beginning of the current weak subjectivity period. These values can be used to construct
-// a weak subjectivity checkpoint beacon node flag to be used for validation.
-type WeakSubjectivityData struct {
-	BlockRoot [32]byte
-	StateRoot [32]byte
-	Epoch     primitives.Epoch
-}
-
-// CheckpointString returns the standard string representation of a Checkpoint.
-// The format is a hex-encoded block root, followed by the epoch of the block, separated by a colon. For example:
-// "0x1c35540cac127315fabb6bf29181f2ae0de1a3fc909d2e76ba771e61312cc49a:74888"
-func (wsd *WeakSubjectivityData) CheckpointString() string {
-	return fmt.Sprintf("%#x:%d", wsd.BlockRoot, wsd.Epoch)
-}
-
-// ComputeWeakSubjectivityCheckpoint attempts to use the prysm weak_subjectivity api
-// to obtain the current weak_subjectivity checkpoint.
-// For non-prysm nodes, the same computation will be performed with extra steps,
-// using the head state downloaded from the beacon node api.
-func ComputeWeakSubjectivityCheckpoint(ctx context.Context, client *Client) (*WeakSubjectivityData, error) {
-	ws, err := client.GetWeakSubjectivity(ctx)
-	if err != nil {
-		// a 404/405 is expected if querying an endpoint that doesn't support the weak subjectivity checkpoint api
-		if !errors.Is(err, base.ErrNotOK) {
-			return nil, errors.Wrap(err, "unexpected API response for prysm-only weak subjectivity checkpoint API")
-		}
-		// fall back to vanilla Beacon Node API method
-		return computeBackwardsCompatible(ctx, client)
-	}
-	log.Printf("server weak subjectivity checkpoint response - epoch=%d, block_root=%#x, state_root=%#x", ws.Epoch, ws.BlockRoot, ws.StateRoot)
-	return ws, nil
-}
-
-const (
-	prysmMinimumVersion     = "v2.0.7"
-	prysmImplementationName = "Prysm"
-)
-
-// errUnsupportedPrysmCheckpointVersion indicates remote beacon node can't be used for checkpoint retrieval.
-var errUnsupportedPrysmCheckpointVersion = errors.New("node does not meet minimum version requirements for checkpoint retrieval")
-
-// for older endpoints or clients that do not support the weak_subjectivity api method
-// we gather the necessary data for a checkpoint sync by:
-// - inspecting the remote server's head state and computing the weak subjectivity epoch locally
-// - requesting the state at the first slot of the epoch
-// - using hash_tree_root(state.latest_block_header) to compute the block the state integrates
-// - requesting that block by its root
-func computeBackwardsCompatible(ctx context.Context, client *Client) (*WeakSubjectivityData, error) {
-	log.Print("falling back to generic checkpoint derivation, weak_subjectivity API not supported by server")
-	nv, err := client.GetNodeVersion(ctx)
-	if err != nil {
-		return nil, errors.Wrap(err, "unable to proceed with fallback method without confirming node version")
-	}
-	if nv.implementation == prysmImplementationName && semver.Compare(nv.semver, prysmMinimumVersion) < 0 {
-		return nil, errors.Wrapf(errUnsupportedPrysmCheckpointVersion, "%s < minimum (%s)", nv.semver, prysmMinimumVersion)
-	}
-	epoch, err := getWeakSubjectivityEpochFromHead(ctx, client)
-	if err != nil {
-		return nil, errors.Wrap(err, "error computing weak subjectivity epoch via head state inspection")
-	}
-
-	// use first slot of the epoch for the state slot
-	slot, err := slots.EpochStart(epoch)
-	if err != nil {
-		return nil, errors.Wrapf(err, "error computing first slot of epoch=%d", epoch)
-	}
-
-	log.Printf("requesting checkpoint state at slot %d", slot)
-	// get the state at the first slot of the epoch
-	sb, err := client.GetState(ctx, IdFromSlot(slot))
-	if err != nil {
-		return nil, errors.Wrapf(err, "failed to request state by slot from api, slot=%d", slot)
-	}
-
-	// ConfigFork is used to unmarshal the BeaconState so we can read the block root in latest_block_header
-	vu, err := detect.FromState(sb)
-	if err != nil {
-		return nil, errors.Wrap(err, "error detecting chain config for beacon state")
-	}
-	log.Printf("detected supported config in checkpoint state, name=%s, fork=%s", vu.Config.ConfigName, version.String(vu.Fork))
-
-	s, err := vu.UnmarshalBeaconState(sb)
-	if err != nil {
-		return nil, errors.Wrap(err, "error using detected config fork to unmarshal state bytes")
-	}
-
-	// compute state and block roots
-	sr, err := s.HashTreeRoot(ctx)
-	if err != nil {
-		return nil, errors.Wrap(err, "error computing hash_tree_root of state")
-	}
-
-	h := s.LatestBlockHeader()
-	h.StateRoot = sr[:]
-	br, err := h.HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "error while computing block root using state data")
-	}
-
-	bb, err := client.GetBlock(ctx, IdFromRoot(br))
-	if err != nil {
-		return nil, errors.Wrapf(err, "error requesting block by root = %d", br)
-	}
-	b, err := vu.UnmarshalBeaconBlock(bb)
-	if err != nil {
-		return nil, errors.Wrap(err, "unable to unmarshal block to a supported type using the detected fork schedule")
-	}
-	br, err = b.Block().HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "error computing hash_tree_root for block obtained via root")
-	}
-
-	return &WeakSubjectivityData{
-		Epoch:     epoch,
-		BlockRoot: br,
-		StateRoot: sr,
-	}, nil
-}
-
-// this method downloads the head state, which can be used to find the correct chain config
-// and use prysm's helper methods to compute the latest weak subjectivity epoch.
-func getWeakSubjectivityEpochFromHead(ctx context.Context, client *Client) (primitives.Epoch, error) {
-	headBytes, err := client.GetState(ctx, IdHead)
-	if err != nil {
-		return 0, err
-	}
-	vu, err := detect.FromState(headBytes)
-	if err != nil {
-		return 0, errors.Wrap(err, "error detecting chain config for beacon state")
-	}
-	log.Printf("detected supported config in remote head state, name=%s, fork=%s", vu.Config.ConfigName, version.String(vu.Fork))
-	headState, err := vu.UnmarshalBeaconState(headBytes)
-	if err != nil {
-		return 0, errors.Wrap(err, "error unmarshaling state to correct version")
-	}
-
-	epoch, err := helpers.LatestWeakSubjectivityEpoch(ctx, headState, vu.Config)
-	if err != nil {
-		return 0, errors.Wrap(err, "error computing the weak subjectivity epoch from head state")
-	}
-
-	log.Printf("(computed client-side) weak subjectivity epoch = %d", epoch)
-	return epoch, nil
-}

api/client/beacon/client.go

@@ -11,17 +11,16 @@ import (
 	"regexp"
 	"sort"
 	"strconv"
-	"text/template"
 
+	"github.com/OffchainLabs/prysm/v6/api/client"
+	"github.com/OffchainLabs/prysm/v6/api/server"
+	"github.com/OffchainLabs/prysm/v6/api/server/structs"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	"github.com/OffchainLabs/prysm/v6/network/forks"
+	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api/client"
-	"github.com/prysmaticlabs/prysm/v5/api/server"
-	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	"github.com/prysmaticlabs/prysm/v5/network/forks"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
 	"github.com/sirupsen/logrus"
 )
 
@@ -29,12 +28,13 @@ const (
 	getSignedBlockPath       = "/eth/v2/beacon/blocks"
 	getBlockRootPath         = "/eth/v1/beacon/blocks/{{.Id}}/root"
 	getForkForStatePath      = "/eth/v1/beacon/states/{{.Id}}/fork"
-	getWeakSubjectivityPath  = "/prysm/v1/beacon/weak_subjectivity"
 	getForkSchedulePath      = "/eth/v1/config/fork_schedule"
 	getConfigSpecPath        = "/eth/v1/config/spec"
 	getStatePath             = "/eth/v2/debug/beacon/states"
-	getNodeVersionPath       = "/eth/v1/node/version"
 	changeBLStoExecutionPath = "/eth/v1/beacon/pool/bls_to_execution_changes"
+
+	GetNodeVersionPath      = "/eth/v1/node/version"
+	GetWeakSubjectivityPath = "/prysm/v1/beacon/weak_subjectivity"
 )
 
 // StateOrBlockId represents the block_id / state_id parameters that several of the Eth Beacon API methods accept.
@@ -63,24 +63,8 @@ func IdFromSlot(s primitives.Slot) StateOrBlockId {
 	return StateOrBlockId(strconv.FormatUint(uint64(s), 10))
 }
 
-// idTemplate is used to create template functions that can interpolate StateOrBlockId values.
-func idTemplate(ts string) func(StateOrBlockId) string {
-	t := template.Must(template.New("").Parse(ts))
-	f := func(id StateOrBlockId) string {
-		b := bytes.NewBuffer(nil)
-		err := t.Execute(b, struct{ Id string }{Id: string(id)})
-		if err != nil {
-			panic(fmt.Sprintf("invalid idTemplate: %s", ts))
-		}
-		return b.String()
-	}
-	// run the template to ensure that it is valid
-	// this should happen load time (using package scoped vars) to ensure runtime errors aren't possible
-	_ = f(IdGenesis)
-	return f
-}
-
-func renderGetBlockPath(id StateOrBlockId) string {
+// RenderGetBlockPath formats a block id into a path for the GetBlock API endpoint.
+func RenderGetBlockPath(id StateOrBlockId) string {
 	return path.Join(getSignedBlockPath, string(id))
 }
 
@@ -104,7 +88,7 @@ func NewClient(host string, opts ...client.ClientOpt) (*Client, error) {
 // for the named identifiers.
 // The return value contains the ssz-encoded bytes.
 func (c *Client) GetBlock(ctx context.Context, blockId StateOrBlockId) ([]byte, error) {
-	blockPath := renderGetBlockPath(blockId)
+	blockPath := RenderGetBlockPath(blockId)
 	b, err := c.Get(ctx, blockPath, client.WithSSZEncoding())
 	if err != nil {
 		return nil, errors.Wrapf(err, "error requesting state by id = %s", blockId)
@@ -112,8 +96,6 @@ func (c *Client) GetBlock(ctx context.Context, blockId StateOrBlockId) ([]byte,
 	return b, nil
 }
 
-var getBlockRootTpl = idTemplate(getBlockRootPath)
-
 // GetBlockRoot retrieves the hash_tree_root of the BeaconBlock for the given block id.
 // Block identifier can be one of: "head" (canonical head in node's view), "genesis", "finalized",
 // <slot>, <hex encoded blockRoot with 0x prefix>. Variables of type StateOrBlockId are exported by this package
@@ -136,8 +118,6 @@ func (c *Client) GetBlockRoot(ctx context.Context, blockId StateOrBlockId) ([32]
 	return bytesutil.ToBytes32(rs), nil
 }
 
-var getForkTpl = idTemplate(getForkForStatePath)
-
 // GetFork queries the Beacon Node API for the Fork from the state identified by stateId.
 // Block identifier can be one of: "head" (canonical head in node's view), "genesis", "finalized",
 // <slot>, <hex encoded blockRoot with 0x prefix>. Variables of type StateOrBlockId are exported by this package
@@ -195,6 +175,10 @@ type NodeVersion struct {
 	systemInfo     string
 }
 
+func (nv *NodeVersion) SetImplementation(impl string) {
+	nv.implementation = impl
+}
+
 var versionRE = regexp.MustCompile(`^(\w+)/(v\d+\.\d+\.\d+[-a-zA-Z0-9]*)\s*/?(.*)$`)
 
 func parseNodeVersion(v string) (*NodeVersion, error) {
@@ -212,7 +196,7 @@ func parseNodeVersion(v string) (*NodeVersion, error) {
 // GetNodeVersion requests that the beacon node identify information about its implementation in a format
 // similar to a HTTP User-Agent field. ex: Lighthouse/v0.1.5 (Linux x86_64)
 func (c *Client) GetNodeVersion(ctx context.Context) (*NodeVersion, error) {
-	b, err := c.Get(ctx, getNodeVersionPath)
+	b, err := c.Get(ctx, GetNodeVersionPath)
 	if err != nil {
 		return nil, errors.Wrap(err, "error requesting node version")
 	}
@@ -228,7 +212,8 @@ func (c *Client) GetNodeVersion(ctx context.Context) (*NodeVersion, error) {
 	return parseNodeVersion(d.Data.Version)
 }
 
-func renderGetStatePath(id StateOrBlockId) string {
+// RenderGetStatePath formats a state id into a path for the GetState API endpoint.
+func RenderGetStatePath(id StateOrBlockId) string {
 	return path.Join(getStatePath, string(id))
 }
 
@@ -246,13 +231,29 @@ func (c *Client) GetState(ctx context.Context, stateId StateOrBlockId) ([]byte,
 	return b, nil
 }
 
+// WeakSubjectivityData represents the state root, block root and epoch of the BeaconState + ReadOnlySignedBeaconBlock
+// that falls at the beginning of the current weak subjectivity period. These values can be used to construct
+// a weak subjectivity checkpoint beacon node flag to be used for validation.
+type WeakSubjectivityData struct {
+	BlockRoot [32]byte
+	StateRoot [32]byte
+	Epoch     primitives.Epoch
+}
+
+// CheckpointString returns the standard string representation of a Checkpoint.
+// The format is a hex-encoded block root, followed by the epoch of the block, separated by a colon. For example:
+// "0x1c35540cac127315fabb6bf29181f2ae0de1a3fc909d2e76ba771e61312cc49a:74888"
+func (wsd *WeakSubjectivityData) CheckpointString() string {
+	return fmt.Sprintf("%#x:%d", wsd.BlockRoot, wsd.Epoch)
+}
+
 // GetWeakSubjectivity calls a proposed API endpoint that is unique to prysm
 // This api method does the following:
 // - computes weak subjectivity epoch
 // - finds the highest non-skipped block preceding the epoch
 // - returns the htr of the found block and returns this + the value of state_root from the block
 func (c *Client) GetWeakSubjectivity(ctx context.Context) (*WeakSubjectivityData, error) {
-	body, err := c.Get(ctx, getWeakSubjectivityPath)
+	body, err := c.Get(ctx, GetWeakSubjectivityPath)
 	if err != nil {
 		return nil, err
 	}

api/client/beacon/client_test.go

@@ -4,8 +4,8 @@ import (
 	"net/url"
 	"testing"
 
-	"github.com/prysmaticlabs/prysm/v5/api/client"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/OffchainLabs/prysm/v6/api/client"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
 )
 
 func TestParseNodeVersion(t *testing.T) {
@@ -97,31 +97,31 @@ func TestValidHostname(t *testing.T) {
 		{
 			name:    "hostname with port",
 			hostArg: "mydomain.org:3500",
-			path:    getNodeVersionPath,
+			path:    GetNodeVersionPath,
 			joined:  "http://mydomain.org:3500/eth/v1/node/version",
 		},
 		{
 			name:    "https scheme, hostname with port",
 			hostArg: "https://mydomain.org:3500",
-			path:    getNodeVersionPath,
+			path:    GetNodeVersionPath,
 			joined:  "https://mydomain.org:3500/eth/v1/node/version",
 		},
 		{
 			name:    "http scheme, hostname without port",
 			hostArg: "http://mydomain.org",
-			path:    getNodeVersionPath,
+			path:    GetNodeVersionPath,
 			joined:  "http://mydomain.org/eth/v1/node/version",
 		},
 		{
 			name:    "http scheme, trailing slash, hostname without port",
 			hostArg: "http://mydomain.org/",
-			path:    getNodeVersionPath,
+			path:    GetNodeVersionPath,
 			joined:  "http://mydomain.org/eth/v1/node/version",
 		},
 		{
 			name:    "http scheme, hostname with basic auth creds and no port",
 			hostArg: "http://username:pass@mydomain.org/",
-			path:    getNodeVersionPath,
+			path:    GetNodeVersionPath,
 			joined:  "http://username:pass@mydomain.org/eth/v1/node/version",
 		},
 	}

api/client/beacon/health/BUILD.bazel

@@ -0,0 +1,20 @@
+load("@prysm//tools/go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "health.go",
+        "interfaces.go",
+        "mock.go",
+    ],
+    importpath = "github.com/OffchainLabs/prysm/v6/api/client/beacon/health",
+    visibility = ["//visibility:public"],
+    deps = ["@org_uber_go_mock//gomock:go_default_library"],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["health_test.go"],
+    embed = [":go_default_library"],
+    deps = ["@org_uber_go_mock//gomock:go_default_library"],
+)

api/client/beacon/health/health.go

@@ -1,20 +1,18 @@
-package beacon
+package health
 
 import (
 	"context"
 	"sync"
-
-	"github.com/prysmaticlabs/prysm/v5/api/client/beacon/iface"
 )
 
 type NodeHealthTracker struct {
 	isHealthy  *bool
 	healthChan chan bool
-	node       iface.HealthNode
+	node       Node
 	sync.RWMutex
 }
 
-func NewNodeHealthTracker(node iface.HealthNode) *NodeHealthTracker {
+func NewTracker(node Node) Tracker {
 	return &NodeHealthTracker{
 		node:       node,
 		healthChan: make(chan bool, 1),
@@ -26,7 +24,7 @@ func (n *NodeHealthTracker) HealthUpdates() <-chan bool {
 	return n.healthChan
 }
 
-func (n *NodeHealthTracker) IsHealthy() bool {
+func (n *NodeHealthTracker) IsHealthy(_ context.Context) bool {
 	n.RLock()
 	defer n.RUnlock()
 	if n.isHealthy == nil {
@@ -36,20 +34,25 @@ func (n *NodeHealthTracker) IsHealthy() bool {
 }
 
 func (n *NodeHealthTracker) CheckHealth(ctx context.Context) bool {
-	n.RLock()
+	n.Lock()
+	defer n.Unlock()
+
 	newStatus := n.node.IsHealthy(ctx)
 	if n.isHealthy == nil {
 		n.isHealthy = &newStatus
 	}
-	isStatusChanged := newStatus != *n.isHealthy
-	n.RUnlock()
 
+	isStatusChanged := newStatus != *n.isHealthy
 	if isStatusChanged {
-		n.Lock()
-		// Double-check the condition to ensure it hasn't changed since the first check.
+		// Update the health status
 		n.isHealthy = &newStatus
-		n.Unlock() // It's better to unlock as soon as the protected section is over.
-		n.healthChan <- newStatus
+		// Send the new status to the health channel, potentially overwriting the existing value
+		select {
+		case <-n.healthChan:
+			n.healthChan <- newStatus
+		default:
+			n.healthChan <- newStatus
+		}
 	}
 	return newStatus
 }

api/client/beacon/health/health_test.go

@@ -1,11 +1,10 @@
-package beacon
+package health
 
 import (
 	"context"
 	"sync"
 	"testing"
 
-	healthTesting "github.com/prysmaticlabs/prysm/v5/api/client/beacon/testing"
 	"go.uber.org/mock/gomock"
 )
 
@@ -24,7 +23,7 @@ func TestNodeHealth_IsHealthy(t *testing.T) {
 				isHealthy:  &tt.isHealthy,
 				healthChan: make(chan bool, 1),
 			}
-			if got := n.IsHealthy(); got != tt.want {
+			if got := n.IsHealthy(context.Background()); got != tt.want {
 				t.Errorf("IsHealthy() = %v, want %v", got, tt.want)
 			}
 		})
@@ -47,7 +46,7 @@ func TestNodeHealth_UpdateNodeHealth(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			ctrl := gomock.NewController(t)
 			defer ctrl.Finish()
-			client := healthTesting.NewMockHealthClient(ctrl)
+			client := NewMockHealthClient(ctrl)
 			client.EXPECT().IsHealthy(gomock.Any()).Return(tt.newStatus)
 			n := &NodeHealthTracker{
 				isHealthy:  &tt.initial,
@@ -80,28 +79,22 @@ func TestNodeHealth_UpdateNodeHealth(t *testing.T) {
 func TestNodeHealth_Concurrency(t *testing.T) {
 	ctrl := gomock.NewController(t)
 	defer ctrl.Finish()
-	client := healthTesting.NewMockHealthClient(ctrl)
-	n := NewNodeHealthTracker(client)
+	client := NewMockHealthClient(ctrl)
+	n := NewTracker(client)
 	var wg sync.WaitGroup
 
 	// Number of goroutines to spawn for both reading and writing
 	numGoroutines := 6
 
-	go func() {
-		for range n.HealthUpdates() {
-			// Consume values to avoid blocking on channel send.
-		}
-	}()
-
 	wg.Add(numGoroutines * 2) // for readers and writers
 
 	// Concurrently update health status
 	for i := 0; i < numGoroutines; i++ {
 		go func() {
 			defer wg.Done()
-			client.EXPECT().IsHealthy(gomock.Any()).Return(false)
+			client.EXPECT().IsHealthy(gomock.Any()).Return(false).Times(1)
 			n.CheckHealth(context.Background())
-			client.EXPECT().IsHealthy(gomock.Any()).Return(true)
+			client.EXPECT().IsHealthy(gomock.Any()).Return(true).Times(1)
 			n.CheckHealth(context.Background())
 		}()
 	}
@@ -110,7 +103,7 @@ func TestNodeHealth_Concurrency(t *testing.T) {
 	for i := 0; i < numGoroutines; i++ {
 		go func() {
 			defer wg.Done()
-			_ = n.IsHealthy() // Just read the value
+			_ = n.IsHealthy(context.Background()) // Just read the value
 		}()
 	}
 

api/client/beacon/health/interfaces.go

@@ -1,13 +1,13 @@
-package iface
+package health
 
 import "context"
 
-type HealthTracker interface {
+type Tracker interface {
 	HealthUpdates() <-chan bool
-	IsHealthy() bool
 	CheckHealth(ctx context.Context) bool
+	Node
 }
 
-type HealthNode interface {
+type Node interface {
 	IsHealthy(ctx context.Context) bool
 }

api/client/beacon/health/mock.go

@@ -1,21 +1,22 @@
-package testing
+package health
 
 import (
 	"context"
 	"reflect"
+	"sync"
 
-	"github.com/prysmaticlabs/prysm/v5/api/client/beacon/iface"
 	"go.uber.org/mock/gomock"
 )
 
 var (
-	_ = iface.HealthNode(&MockHealthClient{})
+	_ = Node(&MockHealthClient{})
 )
 
 // MockHealthClient is a mock of HealthClient interface.
 type MockHealthClient struct {
 	ctrl     *gomock.Controller
 	recorder *MockHealthClientMockRecorder
+	sync.Mutex
 }
 
 // MockHealthClientMockRecorder is the mock recorder for MockHealthClient.
@@ -25,6 +26,8 @@ type MockHealthClientMockRecorder struct {
 
 // IsHealthy mocks base method.
 func (m *MockHealthClient) IsHealthy(arg0 context.Context) bool {
+	m.Lock()
+	defer m.Unlock()
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "IsHealthy", arg0)
 	ret0, ok := ret[0].(bool)
@@ -41,6 +44,8 @@ func (m *MockHealthClient) EXPECT() *MockHealthClientMockRecorder {
 
 // IsHealthy indicates an expected call of IsHealthy.
 func (mr *MockHealthClientMockRecorder) IsHealthy(arg0 any) *gomock.Call {
+	mr.mock.Lock()
+	defer mr.mock.Unlock()
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "IsHealthy", reflect.TypeOf((*MockHealthClient)(nil).IsHealthy), arg0)
 }

api/client/beacon/template.go

@@ -0,0 +1,34 @@
+package beacon
+
+import (
+	"bytes"
+	"fmt"
+	"text/template"
+)
+
+type templateFn func(StateOrBlockId) string
+
+var getBlockRootTpl templateFn
+var getForkTpl templateFn
+
+func init() {
+	// idTemplate is used to create template functions that can interpolate StateOrBlockId values.
+	idTemplate := func(ts string) func(StateOrBlockId) string {
+		t := template.Must(template.New("").Parse(ts))
+		f := func(id StateOrBlockId) string {
+			b := bytes.NewBuffer(nil)
+			err := t.Execute(b, struct{ Id string }{Id: string(id)})
+			if err != nil {
+				panic(fmt.Sprintf("invalid idTemplate: %s", ts))
+			}
+			return b.String()
+		}
+		// run the template to ensure that it is valid
+		// this should happen load time (using package scoped vars) to ensure runtime errors aren't possible
+		_ = f(IdGenesis)
+		return f
+	}
+
+	getBlockRootTpl = idTemplate(getBlockRootPath)
+	getForkTpl = idTemplate(getForkForStatePath)
+}

api/client/beacon/testing/BUILD.bazel

@@ -1,12 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library")
-
-go_library(
-    name = "go_default_library",
-    srcs = ["mock.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/beacon/testing",
-    visibility = ["//visibility:public"],
-    deps = [
-        "//api/client/beacon/iface:go_default_library",
-        "@org_uber_go_mock//gomock:go_default_library",
-    ],
-)

api/client/builder/BUILD.bazel

@@ -8,11 +8,15 @@ go_library(
         "errors.go",
         "types.go",
     ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/builder",
+    importpath = "github.com/OffchainLabs/prysm/v6/api/client/builder",
     visibility = ["//visibility:public"],
     deps = [
+        "//api:go_default_library",
+        "//api/client:go_default_library",
+        "//api/server:go_default_library",
         "//api/server/structs:go_default_library",
         "//config/fieldparams:go_default_library",
+        "//config/params:go_default_library",
         "//consensus-types:go_default_library",
         "//consensus-types/blocks:go_default_library",
         "//consensus-types/interfaces:go_default_library",
@@ -20,14 +24,17 @@ go_library(
         "//encoding/bytesutil:go_default_library",
         "//math:go_default_library",
         "//monitoring/tracing:go_default_library",
+        "//monitoring/tracing/trace:go_default_library",
         "//proto/engine/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//runtime/version:go_default_library",
+        "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_fastssz//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
-        "@io_opencensus_go//trace:go_default_library",
+        "@io_opentelemetry_go_contrib_instrumentation_net_http_otelhttp//:go_default_library",
+        "@org_golang_google_protobuf//proto:go_default_library",
     ],
 )
 
@@ -40,6 +47,7 @@ go_test(
     data = glob(["testdata/**"]),
     embed = [":go_default_library"],
     deps = [
+        "//api:go_default_library",
         "//api/server/structs:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
@@ -49,9 +57,11 @@ go_test(
         "//math:go_default_library",
         "//proto/engine/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
+        "//runtime/version:go_default_library",
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
     ],

api/client/builder/bid.go

@@ -1,13 +1,14 @@
 package builder
 
 import (
-	"github.com/pkg/errors"
+	consensus_types "github.com/OffchainLabs/prysm/v6/consensus-types"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	v1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
+	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	ssz "github.com/prysmaticlabs/fastssz"
-	consensus_types "github.com/prysmaticlabs/prysm/v5/consensus-types"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 )
 
 // SignedBid is an interface describing the method set of a signed builder bid.
@@ -21,8 +22,7 @@ type SignedBid interface {
 // Bid is an interface describing the method set of a builder bid.
 type Bid interface {
 	Header() (interfaces.ExecutionData, error)
-	BlobKzgCommitments() ([][]byte, error)
-	Value() []byte
+	Value() primitives.Wei
 	Pubkey() []byte
 	Version() int
 	IsNil() bool
@@ -30,6 +30,18 @@ type Bid interface {
 	HashTreeRootWith(hh *ssz.Hasher) error
 }
 
+// BidDeneb is an interface that exposes newly added kzg commitments on top of builder bid
+type BidDeneb interface {
+	Bid
+	BlobKzgCommitments() [][]byte
+}
+
+// BidElectra is an interface that exposes the newly added execution requests on top of the builder bid
+type BidElectra interface {
+	BidDeneb
+	ExecutionRequests() *v1.ExecutionRequests
+}
+
 type signedBuilderBid struct {
 	p *ethpb.SignedBuilderBid
 }
@@ -114,19 +126,14 @@ func (b builderBid) Header() (interfaces.ExecutionData, error) {
 	return blocks.WrappedExecutionPayloadHeader(b.p.Header)
 }
 
-// BlobKzgCommitments --
-func (b builderBid) BlobKzgCommitments() ([][]byte, error) {
-	return [][]byte{}, errors.New("blob kzg commitments not available before Deneb")
-}
-
 // Version --
 func (b builderBid) Version() int {
 	return version.Bellatrix
 }
 
 // Value --
-func (b builderBid) Value() []byte {
-	return b.p.Value
+func (b builderBid) Value() primitives.Wei {
+	return primitives.LittleEndianBytesToWei(b.p.Value)
 }
 
 // Pubkey --
@@ -165,12 +172,7 @@ func WrappedBuilderBidCapella(p *ethpb.BuilderBidCapella) (Bid, error) {
 // Header returns the execution data interface.
 func (b builderBidCapella) Header() (interfaces.ExecutionData, error) {
 	// We have to convert big endian to little endian because the value is coming from the execution layer.
-	return blocks.WrappedExecutionPayloadHeaderCapella(b.p.Header, blocks.PayloadValueToWei(b.p.Value))
-}
-
-// BlobKzgCommitments --
-func (b builderBidCapella) BlobKzgCommitments() ([][]byte, error) {
-	return [][]byte{}, errors.New("blob kzg commitments not available before Deneb")
+	return blocks.WrappedExecutionPayloadHeaderCapella(b.p.Header)
 }
 
 // Version --
@@ -179,8 +181,8 @@ func (b builderBidCapella) Version() int {
 }
 
 // Value --
-func (b builderBidCapella) Value() []byte {
-	return b.p.Value
+func (b builderBidCapella) Value() primitives.Wei {
+	return primitives.LittleEndianBytesToWei(b.p.Value)
 }
 
 // Pubkey --
@@ -222,8 +224,8 @@ func (b builderBidDeneb) Version() int {
 }
 
 // Value --
-func (b builderBidDeneb) Value() []byte {
-	return b.p.Value
+func (b builderBidDeneb) Value() primitives.Wei {
+	return primitives.LittleEndianBytesToWei(b.p.Value)
 }
 
 // Pubkey --
@@ -249,12 +251,12 @@ func (b builderBidDeneb) HashTreeRootWith(hh *ssz.Hasher) error {
 // Header --
 func (b builderBidDeneb) Header() (interfaces.ExecutionData, error) {
 	// We have to convert big endian to little endian because the value is coming from the execution layer.
-	return blocks.WrappedExecutionPayloadHeaderDeneb(b.p.Header, blocks.PayloadValueToWei(b.p.Value))
+	return blocks.WrappedExecutionPayloadHeaderDeneb(b.p.Header)
 }
 
 // BlobKzgCommitments --
-func (b builderBidDeneb) BlobKzgCommitments() ([][]byte, error) {
-	return b.p.BlobKzgCommitments, nil
+func (b builderBidDeneb) BlobKzgCommitments() [][]byte {
+	return b.p.BlobKzgCommitments
 }
 
 type signedBuilderBidDeneb struct {
@@ -289,3 +291,95 @@ func (b signedBuilderBidDeneb) Version() int {
 func (b signedBuilderBidDeneb) IsNil() bool {
 	return b.p == nil
 }
+
+type builderBidElectra struct {
+	p *ethpb.BuilderBidElectra
+}
+
+// WrappedBuilderBidElectra is a constructor which wraps a protobuf bid into an interface.
+func WrappedBuilderBidElectra(p *ethpb.BuilderBidElectra) (Bid, error) {
+	w := builderBidElectra{p: p}
+	if w.IsNil() {
+		return nil, consensus_types.ErrNilObjectWrapped
+	}
+	return w, nil
+}
+
+// Version --
+func (b builderBidElectra) Version() int {
+	return version.Electra
+}
+
+// Value --
+func (b builderBidElectra) Value() primitives.Wei {
+	return primitives.LittleEndianBytesToWei(b.p.Value)
+}
+
+// Pubkey --
+func (b builderBidElectra) Pubkey() []byte {
+	return b.p.Pubkey
+}
+
+// IsNil --
+func (b builderBidElectra) IsNil() bool {
+	return b.p == nil
+}
+
+// HashTreeRoot --
+func (b builderBidElectra) HashTreeRoot() ([32]byte, error) {
+	return b.p.HashTreeRoot()
+}
+
+// HashTreeRootWith --
+func (b builderBidElectra) HashTreeRootWith(hh *ssz.Hasher) error {
+	return b.p.HashTreeRootWith(hh)
+}
+
+// Header --
+func (b builderBidElectra) Header() (interfaces.ExecutionData, error) {
+	// We have to convert big endian to little endian because the value is coming from the execution layer.
+	return blocks.WrappedExecutionPayloadHeaderDeneb(b.p.Header)
+}
+
+// ExecutionRequests --
+func (b builderBidElectra) ExecutionRequests() *v1.ExecutionRequests {
+	return b.p.ExecutionRequests // does not copy
+}
+
+// BlobKzgCommitments --
+func (b builderBidElectra) BlobKzgCommitments() [][]byte {
+	return b.p.BlobKzgCommitments
+}
+
+type signedBuilderBidElectra struct {
+	p *ethpb.SignedBuilderBidElectra
+}
+
+// WrappedSignedBuilderBidElectra is a constructor which wraps a protobuf signed bit into an interface.
+func WrappedSignedBuilderBidElectra(p *ethpb.SignedBuilderBidElectra) (SignedBid, error) {
+	w := signedBuilderBidElectra{p: p}
+	if w.IsNil() {
+		return nil, consensus_types.ErrNilObjectWrapped
+	}
+	return w, nil
+}
+
+// Message --
+func (b signedBuilderBidElectra) Message() (Bid, error) {
+	return WrappedBuilderBidElectra(b.p.Message)
+}
+
+// Signature --
+func (b signedBuilderBidElectra) Signature() []byte {
+	return b.p.Signature
+}
+
+// Version --
+func (b signedBuilderBidElectra) Version() int {
+	return version.Electra
+}
+
+// IsNil --
+func (b signedBuilderBidElectra) IsNil() bool {
+	return b.p == nil
+}

api/client/builder/client.go

@@ -6,25 +6,27 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"math/big"
 	"net"
 	"net/http"
 	"net/url"
 	"strings"
 	"text/template"
 
+	"github.com/OffchainLabs/prysm/v6/api"
+	"github.com/OffchainLabs/prysm/v6/api/client"
+	"github.com/OffchainLabs/prysm/v6/api/server/structs"
+	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/monitoring/tracing"
+	"github.com/OffchainLabs/prysm/v6/monitoring/tracing/trace"
+	v1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
+	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 	log "github.com/sirupsen/logrus"
-	"go.opencensus.io/trace"
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 )
 
 const (
@@ -34,9 +36,14 @@ const (
 	postRegisterValidatorPath  = "/eth/v1/builder/validators"
 )
 
-var errMalformedHostname = errors.New("hostname must include port, separated by one colon, like example.com:3500")
-var errMalformedRequest = errors.New("required request data are missing")
-var errNotBlinded = errors.New("submitted block is not blinded")
+var (
+	vrExample             = &ethpb.SignedValidatorRegistrationV1{}
+	vrSize                = vrExample.SizeSSZ()
+	errMalformedHostname  = errors.New("hostname must include port, separated by one colon, like example.com:3500")
+	errMalformedRequest   = errors.New("required request data are missing")
+	errNotBlinded         = errors.New("submitted block is not blinded")
+	errVersionUnsupported = errors.New("version is not supported")
+)
 
 // ClientOpt is a functional option for the Client type (http.Client wrapper)
 type ClientOpt func(*Client)
@@ -51,6 +58,12 @@ func WithObserver(m observer) ClientOpt {
 	}
 }
 
+func WithSSZ() ClientOpt {
+	return func(c *Client) {
+		c.sszEnabled = true
+	}
+}
+
 type requestLogger struct{}
 
 func (*requestLogger) observe(r *http.Request) (e error) {
@@ -94,9 +107,10 @@ type BuilderClient interface {
 
 // Client provides a collection of helper methods for calling Builder API endpoints.
 type Client struct {
-	hc      *http.Client
-	baseURL *url.URL
-	obvs    []observer
+	hc         *http.Client
+	baseURL    *url.URL
+	obvs       []observer
+	sszEnabled bool
 }
 
 // NewClient constructs a new client with the provided options (ex WithTimeout).
@@ -108,7 +122,7 @@ func NewClient(host string, opts ...ClientOpt) (*Client, error) {
 		return nil, err
 	}
 	c := &Client{
-		hc:      &http.Client{},
+		hc:      &http.Client{Transport: otelhttp.NewTransport(http.DefaultTransport)},
 		baseURL: u,
 	}
 	for _, o := range opts {
@@ -138,7 +152,7 @@ func (c *Client) NodeURL() string {
 type reqOption func(*http.Request)
 
 // do is a generic, opinionated request function to reduce boilerplate amongst the methods in this package api/client/builder.
-func (c *Client) do(ctx context.Context, method string, path string, body io.Reader, opts ...reqOption) (res []byte, err error) {
+func (c *Client) do(ctx context.Context, method string, path string, body io.Reader, opts ...reqOption) (res []byte, header http.Header, err error) {
 	ctx, span := trace.StartSpan(ctx, "builder.client.do")
 	defer func() {
 		tracing.AnnotateError(span, err)
@@ -147,7 +161,7 @@ func (c *Client) do(ctx context.Context, method string, path string, body io.Rea
 
 	u := c.baseURL.ResolveReference(&url.URL{Path: path})
 
-	span.AddAttributes(trace.StringAttribute("url", u.String()),
+	span.SetAttributes(trace.StringAttribute("url", u.String()),
 		trace.StringAttribute("method", method))
 
 	req, err := http.NewRequestWithContext(ctx, method, u.String(), body)
@@ -177,11 +191,12 @@ func (c *Client) do(ctx context.Context, method string, path string, body io.Rea
 		err = non200Err(r)
 		return
 	}
-	res, err = io.ReadAll(r.Body)
+	res, err = io.ReadAll(io.LimitReader(r.Body, client.MaxBodySize))
 	if err != nil {
 		err = errors.Wrap(err, "error reading http response body from builder server")
 		return
 	}
+	header = r.Header
 	return
 }
 
@@ -211,48 +226,145 @@ func (c *Client) GetHeader(ctx context.Context, slot primitives.Slot, parentHash
 	if err != nil {
 		return nil, err
 	}
-	hb, err := c.do(ctx, http.MethodGet, path, nil)
+	var getOpts reqOption
+	if c.sszEnabled {
+		getOpts = func(r *http.Request) {
+			r.Header.Set("Accept", api.OctetStreamMediaType)
+		}
+	} else {
+		getOpts = func(r *http.Request) {
+			r.Header.Set("Accept", api.JsonMediaType)
+		}
+	}
+	data, header, err := c.do(ctx, http.MethodGet, path, nil, getOpts)
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(err, "error getting header from builder server")
 	}
-	v := &VersionResponse{}
-	if err := json.Unmarshal(hb, v); err != nil {
-		return nil, errors.Wrapf(err, "error unmarshaling the builder GetHeader response, using slot=%d, parentHash=%#x, pubkey=%#x", slot, parentHash, pubkey)
+
+	bid, err := c.parseHeaderResponse(data, header)
+	if err != nil {
+		return nil, errors.Wrapf(
+			err,
+			"error rendering exec header template with slot=%d, parentHash=%#x, pubkey=%#x",
+			slot,
+			parentHash,
+			pubkey,
+		)
 	}
-	switch strings.ToLower(v.Version) {
-	case strings.ToLower(version.String(version.Deneb)):
-		hr := &ExecHeaderResponseDeneb{}
-		if err := json.Unmarshal(hb, hr); err != nil {
-			return nil, errors.Wrapf(err, "error unmarshaling the builder GetHeader response, using slot=%d, parentHash=%#x, pubkey=%#x", slot, parentHash, pubkey)
+	return bid, nil
+}
+
+func (c *Client) parseHeaderResponse(data []byte, header http.Header) (SignedBid, error) {
+	var versionHeader string
+	if c.sszEnabled || header.Get(api.VersionHeader) != "" {
+		versionHeader = header.Get(api.VersionHeader)
+	} else {
+		// If we don't have a version header, attempt to parse JSON for version
+		v := &VersionResponse{}
+		if err := json.Unmarshal(data, v); err != nil {
+			return nil, errors.Wrap(
+				err,
+				"error unmarshaling builder GetHeader response",
+			)
 		}
-		p, err := hr.ToProto()
-		if err != nil {
-			return nil, errors.Wrapf(err, "could not extract proto message from header")
-		}
-		return WrappedSignedBuilderBidDeneb(p)
-	case strings.ToLower(version.String(version.Capella)):
-		hr := &ExecHeaderResponseCapella{}
-		if err := json.Unmarshal(hb, hr); err != nil {
-			return nil, errors.Wrapf(err, "error unmarshaling the builder GetHeader response, using slot=%d, parentHash=%#x, pubkey=%#x", slot, parentHash, pubkey)
-		}
-		p, err := hr.ToProto()
-		if err != nil {
-			return nil, errors.Wrapf(err, "could not extract proto message from header")
-		}
-		return WrappedSignedBuilderBidCapella(p)
-	case strings.ToLower(version.String(version.Bellatrix)):
-		hr := &ExecHeaderResponse{}
-		if err := json.Unmarshal(hb, hr); err != nil {
-			return nil, errors.Wrapf(err, "error unmarshaling the builder GetHeader response, using slot=%d, parentHash=%#x, pubkey=%#x", slot, parentHash, pubkey)
-		}
-		p, err := hr.ToProto()
-		if err != nil {
-			return nil, errors.Wrap(err, "could not extract proto message from header")
-		}
-		return WrappedSignedBuilderBid(p)
-	default:
-		return nil, fmt.Errorf("unsupported header version %s", strings.ToLower(v.Version))
+		versionHeader = strings.ToLower(v.Version)
 	}
+
+	ver, err := version.FromString(versionHeader)
+	if err != nil {
+		return nil, errors.Wrap(err, fmt.Sprintf("unsupported header version %s", versionHeader))
+	}
+
+	if ver >= version.Electra {
+		return c.parseHeaderElectra(data)
+	}
+	if ver >= version.Deneb {
+		return c.parseHeaderDeneb(data)
+	}
+	if ver >= version.Capella {
+		return c.parseHeaderCapella(data)
+	}
+	if ver >= version.Bellatrix {
+		return c.parseHeaderBellatrix(data)
+	}
+
+	return nil, fmt.Errorf("unsupported header version %s", versionHeader)
+}
+
+func (c *Client) parseHeaderElectra(data []byte) (SignedBid, error) {
+	if c.sszEnabled {
+		sb := &ethpb.SignedBuilderBidElectra{}
+		if err := sb.UnmarshalSSZ(data); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal SignedBuilderBidElectra SSZ")
+		}
+		return WrappedSignedBuilderBidElectra(sb)
+	}
+	hr := &ExecHeaderResponseElectra{}
+	if err := json.Unmarshal(data, hr); err != nil {
+		return nil, errors.Wrap(err, "could not unmarshal ExecHeaderResponseElectra JSON")
+	}
+	p, err := hr.ToProto()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not convert ExecHeaderResponseElectra to proto")
+	}
+	return WrappedSignedBuilderBidElectra(p)
+}
+
+func (c *Client) parseHeaderDeneb(data []byte) (SignedBid, error) {
+	if c.sszEnabled {
+		sb := &ethpb.SignedBuilderBidDeneb{}
+		if err := sb.UnmarshalSSZ(data); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal SignedBuilderBidDeneb SSZ")
+		}
+		return WrappedSignedBuilderBidDeneb(sb)
+	}
+	hr := &ExecHeaderResponseDeneb{}
+	if err := json.Unmarshal(data, hr); err != nil {
+		return nil, errors.Wrap(err, "could not unmarshal ExecHeaderResponseDeneb JSON")
+	}
+	p, err := hr.ToProto()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not convert ExecHeaderResponseDeneb to proto")
+	}
+	return WrappedSignedBuilderBidDeneb(p)
+}
+
+func (c *Client) parseHeaderCapella(data []byte) (SignedBid, error) {
+	if c.sszEnabled {
+		sb := &ethpb.SignedBuilderBidCapella{}
+		if err := sb.UnmarshalSSZ(data); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal SignedBuilderBidCapella SSZ")
+		}
+		return WrappedSignedBuilderBidCapella(sb)
+	}
+	hr := &ExecHeaderResponseCapella{}
+	if err := json.Unmarshal(data, hr); err != nil {
+		return nil, errors.Wrap(err, "could not unmarshal ExecHeaderResponseCapella JSON")
+	}
+	p, err := hr.ToProto()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not convert ExecHeaderResponseCapella to proto")
+	}
+	return WrappedSignedBuilderBidCapella(p)
+}
+
+func (c *Client) parseHeaderBellatrix(data []byte) (SignedBid, error) {
+	if c.sszEnabled {
+		sb := &ethpb.SignedBuilderBid{}
+		if err := sb.UnmarshalSSZ(data); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal SignedBuilderBid SSZ")
+		}
+		return WrappedSignedBuilderBid(sb)
+	}
+	hr := &ExecHeaderResponse{}
+	if err := json.Unmarshal(data, hr); err != nil {
+		return nil, errors.Wrap(err, "could not unmarshal ExecHeaderResponse JSON")
+	}
+	p, err := hr.ToProto()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not convert ExecHeaderResponse to proto")
+	}
+	return WrappedSignedBuilderBid(p)
 }
 
 // RegisterValidator encodes the SignedValidatorRegistrationV1 message to json (including hex-encoding the byte
@@ -260,167 +372,284 @@ func (c *Client) GetHeader(ctx context.Context, slot primitives.Slot, parentHash
 func (c *Client) RegisterValidator(ctx context.Context, svr []*ethpb.SignedValidatorRegistrationV1) error {
 	ctx, span := trace.StartSpan(ctx, "builder.client.RegisterValidator")
 	defer span.End()
-	span.AddAttributes(trace.Int64Attribute("num_reqs", int64(len(svr))))
+	span.SetAttributes(trace.Int64Attribute("num_reqs", int64(len(svr))))
 
 	if len(svr) == 0 {
 		err := errors.Wrap(errMalformedRequest, "empty validator registration list")
 		tracing.AnnotateError(span, err)
 		return err
 	}
+
+	var (
+		body     []byte
+		err      error
+		postOpts reqOption
+	)
+	if c.sszEnabled {
+		postOpts = func(r *http.Request) {
+			r.Header.Set("Content-Type", api.OctetStreamMediaType)
+			r.Header.Set("Accept", api.OctetStreamMediaType)
+		}
+		body, err = sszValidatorRegisterRequest(svr)
+		if err != nil {
+			err := errors.Wrap(err, "error ssz encoding the SignedValidatorRegistration value body in RegisterValidator")
+			tracing.AnnotateError(span, err)
+			return err
+		}
+	} else {
+		postOpts = func(r *http.Request) {
+			r.Header.Set("Content-Type", api.JsonMediaType)
+			r.Header.Set("Accept", api.JsonMediaType)
+		}
+		body, err = jsonValidatorRegisterRequest(svr)
+		if err != nil {
+			err := errors.Wrap(err, "error json encoding the SignedValidatorRegistration value body in RegisterValidator")
+			tracing.AnnotateError(span, err)
+			return err
+		}
+	}
+
+	if _, _, err = c.do(ctx, http.MethodPost, postRegisterValidatorPath, bytes.NewBuffer(body), postOpts); err != nil {
+		return errors.Wrap(err, "do")
+	}
+	log.WithField("registrationCount", len(svr)).Debug("Successfully registered validator(s) on builder")
+	return nil
+}
+
+func jsonValidatorRegisterRequest(svr []*ethpb.SignedValidatorRegistrationV1) ([]byte, error) {
 	vs := make([]*structs.SignedValidatorRegistration, len(svr))
 	for i := 0; i < len(svr); i++ {
 		vs[i] = structs.SignedValidatorRegistrationFromConsensus(svr[i])
 	}
 	body, err := json.Marshal(vs)
 	if err != nil {
-		err := errors.Wrap(err, "error encoding the SignedValidatorRegistration value body in RegisterValidator")
-		tracing.AnnotateError(span, err)
-		return err
+		return nil, err
 	}
+	return body, nil
+}
 
-	_, err = c.do(ctx, http.MethodPost, postRegisterValidatorPath, bytes.NewBuffer(body))
-	return err
+func sszValidatorRegisterRequest(svr []*ethpb.SignedValidatorRegistrationV1) ([]byte, error) {
+	if uint64(len(svr)) > params.BeaconConfig().ValidatorRegistryLimit {
+		return nil, errors.Wrap(errMalformedRequest, "validator registry limit exceeded")
+	}
+	ssz := make([]byte, vrSize*len(svr))
+	for i, vr := range svr {
+		sszrep, err := vr.MarshalSSZ()
+		if err != nil {
+			return nil, errors.Wrap(err, "failed to marshal validator registry ssz")
+		}
+		copy(ssz[i*vrSize:(i+1)*vrSize], sszrep)
+	}
+	return ssz, nil
+}
+
+var errResponseVersionMismatch = errors.New("builder API response uses a different version than requested in " + api.VersionHeader + " header")
+
+func getVersionsBlockToPayload(blockVersion int) (int, error) {
+	if blockVersion >= version.Deneb {
+		return version.Deneb, nil
+	}
+	if blockVersion == version.Capella {
+		return version.Capella, nil
+	}
+	if blockVersion == version.Bellatrix {
+		return version.Bellatrix, nil
+	}
+	return 0, errors.Wrapf(errVersionUnsupported, "block version %d", blockVersion)
 }
 
 // SubmitBlindedBlock calls the builder API endpoint that binds the validator to the builder and submits the block.
 // The response is the full execution payload used to create the blinded block.
 func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, *v1.BlobsBundle, error) {
+	body, postOpts, err := c.buildBlindedBlockRequest(sb)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// post the blinded block - the execution payload response should contain the unblinded payload, along with the
+	// blobs bundle if it is post deneb.
+	data, header, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), postOpts)
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "error posting the blinded block to the builder api")
+	}
+
+	ver, err := c.checkBlockVersion(data, header)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	expectedPayloadVer, err := getVersionsBlockToPayload(sb.Version())
+	if err != nil {
+		return nil, nil, err
+	}
+	gotPayloadVer, err := getVersionsBlockToPayload(ver)
+	if err != nil {
+		return nil, nil, err
+	}
+	if expectedPayloadVer != gotPayloadVer {
+		return nil, nil, errors.Wrapf(errResponseVersionMismatch, "expected payload version %d, got %d", expectedPayloadVer, gotPayloadVer)
+	}
+
+	ed, blobs, err := c.parseBlindedBlockResponse(data, ver)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return ed, blobs, nil
+}
+
+func (c *Client) checkBlockVersion(respBytes []byte, header http.Header) (int, error) {
+	var versionHeader string
+	if c.sszEnabled {
+		versionHeader = strings.ToLower(header.Get(api.VersionHeader))
+	} else {
+		// fallback to JSON-based version extraction
+		v := &VersionResponse{}
+		if err := json.Unmarshal(respBytes, v); err != nil {
+			return 0, errors.Wrapf(err, "error unmarshaling JSON version fallback")
+		}
+		versionHeader = strings.ToLower(v.Version)
+	}
+
+	ver, err := version.FromString(versionHeader)
+	if err != nil {
+		return 0, errors.Wrapf(err, "unsupported header version %s", versionHeader)
+	}
+
+	return ver, nil
+}
+
+// Helper: build request body for SubmitBlindedBlock
+func (c *Client) buildBlindedBlockRequest(sb interfaces.ReadOnlySignedBeaconBlock) ([]byte, reqOption, error) {
 	if !sb.IsBlinded() {
 		return nil, nil, errNotBlinded
 	}
-	switch sb.Version() {
-	case version.Bellatrix:
-		psb, err := sb.PbBlindedBellatrixBlock()
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not get protobuf block")
-		}
-		b, err := structs.SignedBlindedBeaconBlockBellatrixFromConsensus(&ethpb.SignedBlindedBeaconBlockBellatrix{Block: psb.Block, Signature: bytesutil.SafeCopyBytes(psb.Signature)})
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not convert SignedBlindedBeaconBlockBellatrix to json marshalable type")
-		}
-		body, err := json.Marshal(b)
-		if err != nil {
-			return nil, nil, errors.Wrap(err, "error encoding the SignedBlindedBeaconBlockBellatrix value body in SubmitBlindedBlock")
-		}
-		versionOpt := func(r *http.Request) {
-			r.Header.Add("Eth-Consensus-Version", version.String(version.Bellatrix))
-			r.Header.Set("Content-Type", "application/json")
-			r.Header.Set("Accept", "application/json")
-		}
-		rb, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), versionOpt)
 
+	if c.sszEnabled {
+		body, err := sb.MarshalSSZ()
 		if err != nil {
-			return nil, nil, errors.Wrap(err, "error posting the SignedBlindedBeaconBlockBellatrix to the builder api")
+			return nil, nil, errors.Wrap(err, "could not marshal SSZ for blinded block")
 		}
-		ep := &ExecPayloadResponse{}
-		if err := json.Unmarshal(rb, ep); err != nil {
-			return nil, nil, errors.Wrap(err, "error unmarshaling the builder SubmitBlindedBlock response")
+		opt := func(r *http.Request) {
+			r.Header.Set(api.VersionHeader, version.String(sb.Version()))
+			r.Header.Set("Content-Type", api.OctetStreamMediaType)
+			r.Header.Set("Accept", api.OctetStreamMediaType)
 		}
-		if strings.ToLower(ep.Version) != version.String(version.Bellatrix) {
-			return nil, nil, errors.New("not a bellatrix payload")
-		}
-		p, err := ep.ToProto()
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not extract proto message from payload")
-		}
-		payload, err := blocks.WrappedExecutionPayload(p)
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not wrap execution payload in interface")
-		}
-		return payload, nil, nil
-	case version.Capella:
-		psb, err := sb.PbBlindedCapellaBlock()
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not get protobuf block")
-		}
-		b, err := structs.SignedBlindedBeaconBlockCapellaFromConsensus(&ethpb.SignedBlindedBeaconBlockCapella{Block: psb.Block, Signature: bytesutil.SafeCopyBytes(psb.Signature)})
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not convert SignedBlindedBeaconBlockCapella to json marshalable type")
-		}
-		body, err := json.Marshal(b)
-		if err != nil {
-			return nil, nil, errors.Wrap(err, "error encoding the SignedBlindedBeaconBlockCapella value body in SubmitBlindedBlockCapella")
-		}
-		versionOpt := func(r *http.Request) {
-			r.Header.Add("Eth-Consensus-Version", version.String(version.Capella))
-			r.Header.Set("Content-Type", "application/json")
-			r.Header.Set("Accept", "application/json")
-		}
-		rb, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), versionOpt)
-
-		if err != nil {
-			return nil, nil, errors.Wrap(err, "error posting the SignedBlindedBeaconBlockCapella to the builder api")
-		}
-		ep := &ExecPayloadResponseCapella{}
-		if err := json.Unmarshal(rb, ep); err != nil {
-			return nil, nil, errors.Wrap(err, "error unmarshaling the builder SubmitBlindedBlockCapella response")
-		}
-		if strings.ToLower(ep.Version) != version.String(version.Capella) {
-			return nil, nil, errors.New("not a capella payload")
-		}
-		p, err := ep.ToProto()
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not extract proto message from payload")
-		}
-		payload, err := blocks.WrappedExecutionPayloadCapella(p, big.NewInt(0))
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not wrap execution payload in interface")
-		}
-		return payload, nil, nil
-	case version.Deneb:
-		psb, err := sb.PbBlindedDenebBlock()
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not get protobuf block")
-		}
-		b, err := structs.SignedBlindedBeaconBlockDenebFromConsensus(&ethpb.SignedBlindedBeaconBlockDeneb{Message: psb.Message, Signature: bytesutil.SafeCopyBytes(psb.Signature)})
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not convert SignedBlindedBeaconBlockDeneb to json marshalable type")
-		}
-		body, err := json.Marshal(b)
-		if err != nil {
-			return nil, nil, errors.Wrap(err, "error encoding the SignedBlindedBeaconBlockDeneb value body in SubmitBlindedBlockDeneb")
-		}
-
-		versionOpt := func(r *http.Request) {
-			r.Header.Add("Eth-Consensus-Version", version.String(version.Deneb))
-			r.Header.Set("Content-Type", "application/json")
-			r.Header.Set("Accept", "application/json")
-		}
-		rb, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), versionOpt)
-		if err != nil {
-			return nil, nil, errors.Wrap(err, "error posting the SignedBlindedBeaconBlockDeneb to the builder api")
-		}
-		ep := &ExecPayloadResponseDeneb{}
-		if err := json.Unmarshal(rb, ep); err != nil {
-			return nil, nil, errors.Wrap(err, "error unmarshaling the builder SubmitBlindedBlockDeneb response")
-		}
-		if strings.ToLower(ep.Version) != version.String(version.Deneb) {
-			return nil, nil, errors.New("not a deneb payload")
-		}
-		p, blobBundle, err := ep.ToProto()
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not extract proto message from payload")
-		}
-		payload, err := blocks.WrappedExecutionPayloadDeneb(p, big.NewInt(0))
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "could not wrap execution payload in interface")
-		}
-		return payload, blobBundle, nil
-	default:
-		return nil, nil, fmt.Errorf("unsupported block version %s", version.String(sb.Version()))
+		return body, opt, nil
 	}
+
+	mj, err := structs.SignedBeaconBlockMessageJsoner(sb)
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "error generating blinded beacon block post request")
+	}
+	body, err := json.Marshal(mj)
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "error marshaling blinded block to JSON")
+	}
+	opt := func(r *http.Request) {
+		r.Header.Set(api.VersionHeader, version.String(sb.Version()))
+		r.Header.Set("Content-Type", api.JsonMediaType)
+		r.Header.Set("Accept", api.JsonMediaType)
+	}
+	return body, opt, nil
+}
+
+// Helper: parse the response returned by SubmitBlindedBlock
+func (c *Client) parseBlindedBlockResponse(
+	respBytes []byte,
+	forkVersion int,
+) (interfaces.ExecutionData, *v1.BlobsBundle, error) {
+	if c.sszEnabled {
+		return c.parseBlindedBlockResponseSSZ(respBytes, forkVersion)
+	}
+	return c.parseBlindedBlockResponseJSON(respBytes, forkVersion)
+}
+
+func (c *Client) parseBlindedBlockResponseSSZ(
+	respBytes []byte,
+	forkVersion int,
+) (interfaces.ExecutionData, *v1.BlobsBundle, error) {
+	if forkVersion >= version.Deneb {
+		payloadAndBlobs := &v1.ExecutionPayloadDenebAndBlobsBundle{}
+		if err := payloadAndBlobs.UnmarshalSSZ(respBytes); err != nil {
+			return nil, nil, errors.Wrap(err, "unable to unmarshal ExecutionPayloadDenebAndBlobsBundle SSZ")
+		}
+		ed, err := blocks.NewWrappedExecutionData(payloadAndBlobs.Payload)
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "unable to wrap execution data for %s", version.String(forkVersion))
+		}
+		return ed, payloadAndBlobs.BlobsBundle, nil
+	} else if forkVersion >= version.Capella {
+		payload := &v1.ExecutionPayloadCapella{}
+		if err := payload.UnmarshalSSZ(respBytes); err != nil {
+			return nil, nil, errors.Wrap(err, "unable to unmarshal ExecutionPayloadCapella SSZ")
+		}
+		ed, err := blocks.NewWrappedExecutionData(payload)
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "unable to wrap execution data for %s", version.String(forkVersion))
+		}
+		return ed, nil, nil
+	} else if forkVersion >= version.Bellatrix {
+		payload := &v1.ExecutionPayload{}
+		if err := payload.UnmarshalSSZ(respBytes); err != nil {
+			return nil, nil, errors.Wrap(err, "unable to unmarshal ExecutionPayload SSZ")
+		}
+		ed, err := blocks.NewWrappedExecutionData(payload)
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "unable to wrap execution data for %s", version.String(forkVersion))
+		}
+		return ed, nil, nil
+	} else {
+		return nil, nil, fmt.Errorf("unsupported header version %s", version.String(forkVersion))
+	}
+}
+
+func (c *Client) parseBlindedBlockResponseJSON(
+	respBytes []byte,
+	forkVersion int,
+) (interfaces.ExecutionData, *v1.BlobsBundle, error) {
+	ep := &ExecutionPayloadResponse{}
+	if err := json.Unmarshal(respBytes, ep); err != nil {
+		return nil, nil, errors.Wrap(err, "error unmarshaling ExecutionPayloadResponse")
+	}
+	pp, err := ep.ParsePayload()
+	if err != nil {
+		return nil, nil, errors.Wrapf(err, "failed to parse payload with version=%s", ep.Version)
+	}
+	pb, err := pp.PayloadProto()
+	if err != nil {
+		return nil, nil, err
+	}
+	ed, err := blocks.NewWrappedExecutionData(pb)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Check if it contains blobs
+	bb, ok := pp.(BlobBundler)
+	if ok {
+		bbpb, err := bb.BundleProto()
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "failed to extract blobs bundle from version=%s", ep.Version)
+		}
+		return ed, bbpb, nil
+	}
+	return ed, nil, nil
 }
 
 // Status asks the remote builder server for a health check. A response of 200 with an empty body is the success/healthy
 // response, and an error response may have an error message. This method will return a nil value for error in the
 // happy path, and an error with information about the server response body for a non-200 response.
 func (c *Client) Status(ctx context.Context) error {
-	_, err := c.do(ctx, http.MethodGet, getStatus, nil)
+	getOpts := func(r *http.Request) {
+		r.Header.Set("Accept", api.JsonMediaType)
+	}
+	_, _, err := c.do(ctx, http.MethodGet, getStatus, nil, getOpts)
 	return err
 }
 
 func non200Err(response *http.Response) error {
-	bodyBytes, err := io.ReadAll(response.Body)
+	bodyBytes, err := io.ReadAll(io.LimitReader(response.Body, client.MaxErrBodySize))
 	var errMessage ErrorMessage
 	var body string
 	if err != nil {
@@ -430,6 +659,18 @@ func non200Err(response *http.Response) error {
 	}
 	msg := fmt.Sprintf("code=%d, url=%s, body=%s", response.StatusCode, response.Request.URL, body)
 	switch response.StatusCode {
+	case http.StatusUnsupportedMediaType:
+		log.WithError(ErrUnsupportedMediaType).Debug(msg)
+		if jsonErr := json.Unmarshal(bodyBytes, &errMessage); jsonErr != nil {
+			return errors.Wrap(jsonErr, "unable to read response body")
+		}
+		return errors.Wrap(ErrUnsupportedMediaType, errMessage.Message)
+	case http.StatusNotAcceptable:
+		log.WithError(ErrNotAcceptable).Debug(msg)
+		if jsonErr := json.Unmarshal(bodyBytes, &errMessage); jsonErr != nil {
+			return errors.Wrap(jsonErr, "unable to read response body")
+		}
+		return errors.Wrap(ErrNotAcceptable, errMessage.Message)
 	case http.StatusNoContent:
 		log.WithError(ErrNoContent).Debug(msg)
 		return ErrNoContent

api/client/builder/client_test.go

@@ -6,22 +6,21 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"math/big"
 	"net/http"
 	"net/url"
-	"strconv"
 	"testing"
 
+	"github.com/OffchainLabs/prysm/v6/api"
+	"github.com/OffchainLabs/prysm/v6/api/server/structs"
+	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	v1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
+	eth "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/prysmaticlabs/go-bitfield"
-	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
-	"github.com/prysmaticlabs/prysm/v5/config/params"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	types "github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -88,43 +87,90 @@ func TestClient_RegisterValidator(t *testing.T) {
 	ctx := context.Background()
 	expectedBody := `[{"message":{"fee_recipient":"0x0000000000000000000000000000000000000000","gas_limit":"23","timestamp":"42","pubkey":"0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"},"signature":"0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"}]`
 	expectedPath := "/eth/v1/builder/validators"
-	hc := &http.Client{
-		Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
-			body, err := io.ReadAll(r.Body)
-			defer func() {
-				require.NoError(t, r.Body.Close())
-			}()
-			require.NoError(t, err)
-			require.Equal(t, expectedBody, string(body))
-			require.Equal(t, expectedPath, r.URL.Path)
-			require.Equal(t, http.MethodPost, r.Method)
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewBuffer(nil)),
-				Request:    r.Clone(ctx),
-			}, nil
-		}),
-	}
-	c := &Client{
-		hc:      hc,
-		baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
-	}
-	reg := &eth.SignedValidatorRegistrationV1{
-		Message: &eth.ValidatorRegistrationV1{
-			FeeRecipient: ezDecode(t, params.BeaconConfig().EthBurnAddressHex),
-			GasLimit:     23,
-			Timestamp:    42,
-			Pubkey:       ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"),
-		},
-		Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
-	}
-	require.NoError(t, c.RegisterValidator(ctx, []*eth.SignedValidatorRegistrationV1{reg}))
+	t.Run("JSON success", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
+				body, err := io.ReadAll(r.Body)
+				defer func() {
+					require.NoError(t, r.Body.Close())
+				}()
+				require.NoError(t, err)
+				require.Equal(t, expectedBody, string(body))
+				require.Equal(t, expectedPath, r.URL.Path)
+				require.Equal(t, http.MethodPost, r.Method)
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body:       io.NopCloser(bytes.NewBuffer(nil)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+		reg := &eth.SignedValidatorRegistrationV1{
+			Message: &eth.ValidatorRegistrationV1{
+				FeeRecipient: ezDecode(t, params.BeaconConfig().EthBurnAddressHex),
+				GasLimit:     23,
+				Timestamp:    42,
+				Pubkey:       ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"),
+			},
+			Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+		}
+		require.NoError(t, c.RegisterValidator(ctx, []*eth.SignedValidatorRegistrationV1{reg}))
+	})
+	t.Run("SSZ success", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Accept"))
+				body, err := io.ReadAll(r.Body)
+				defer func() {
+					require.NoError(t, r.Body.Close())
+				}()
+				require.NoError(t, err)
+				request := &eth.SignedValidatorRegistrationV1{}
+				itemBytes := body[:request.SizeSSZ()]
+				require.NoError(t, request.UnmarshalSSZ(itemBytes))
+				jsRequest := structs.SignedValidatorRegistrationFromConsensus(request)
+				js, err := json.Marshal([]*structs.SignedValidatorRegistration{jsRequest})
+				require.NoError(t, err)
+
+				require.Equal(t, expectedBody, string(js))
+				require.Equal(t, expectedPath, r.URL.Path)
+				require.Equal(t, http.MethodPost, r.Method)
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body:       io.NopCloser(bytes.NewBuffer(nil)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:         hc,
+			baseURL:    &url.URL{Host: "localhost:3500", Scheme: "http"},
+			sszEnabled: true,
+		}
+		reg := &eth.SignedValidatorRegistrationV1{
+			Message: &eth.ValidatorRegistrationV1{
+				FeeRecipient: ezDecode(t, params.BeaconConfig().EthBurnAddressHex),
+				GasLimit:     23,
+				Timestamp:    42,
+				Pubkey:       ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"),
+			},
+			Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+		}
+		require.NoError(t, c.RegisterValidator(ctx, []*eth.SignedValidatorRegistrationV1{reg}))
+	})
 }
 
 func TestClient_GetHeader(t *testing.T) {
 	ctx := context.Background()
 	expectedPath := "/eth/v1/builder/header/23/0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2/0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"
-	var slot types.Slot = 23
+	var slot primitives.Slot = 23
 	parentHash := ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
 	pubkey := ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a")
 	t.Run("server error", func(t *testing.T) {
@@ -174,6 +220,7 @@ func TestClient_GetHeader(t *testing.T) {
 		hc := &http.Client{
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
 				require.Equal(t, expectedPath, r.URL.Path)
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
 				return &http.Response{
 					StatusCode: http.StatusOK,
 					Body:       io.NopCloser(bytes.NewBufferString(testExampleHeaderResponse)),
@@ -198,16 +245,63 @@ func TestClient_GetHeader(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, true, bytes.Equal(expectedTxRoot, withdrawalsRoot))
 		require.Equal(t, uint64(1), bidHeader.GasUsed())
-		value, err := stringToUint256("652312848583266388373324160190187140051835877600158453279131187530910662656")
+		// this matches the value in the testExampleHeaderResponse
+		bidStr := "652312848583266388373324160190187140051835877600158453279131187530910662656"
+		value, err := stringToUint256(bidStr)
 		require.NoError(t, err)
-		require.Equal(t, fmt.Sprintf("%#x", value.SSZBytes()), fmt.Sprintf("%#x", bid.Value()))
-		bidValue := bytesutil.ReverseByteOrder(bid.Value())
-		require.DeepEqual(t, bidValue, value.Bytes())
-		require.DeepEqual(t, big.NewInt(0).SetBytes(bidValue), value.Int)
+		require.Equal(t, 0, value.Int.Cmp(primitives.WeiToBigInt(bid.Value())))
+		require.Equal(t, bidStr, primitives.WeiToBigInt(bid.Value()).String())
+	})
+	t.Run("bellatrix ssz", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Accept"))
+				require.Equal(t, expectedPath, r.URL.Path)
+				epr := &ExecHeaderResponse{}
+				require.NoError(t, json.Unmarshal([]byte(testExampleHeaderResponse), epr))
+				pro, err := epr.ToProto()
+				require.NoError(t, err)
+				ssz, err := pro.MarshalSSZ()
+				require.NoError(t, err)
+				header := http.Header{}
+				header.Set(api.VersionHeader, "bellatrix")
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Header:     header,
+					Body:       io.NopCloser(bytes.NewBuffer(ssz)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:         hc,
+			baseURL:    &url.URL{Host: "localhost:3500", Scheme: "http"},
+			sszEnabled: true,
+		}
+		h, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
+		require.NoError(t, err)
+		expectedSig := ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505")
+		require.Equal(t, true, bytes.Equal(expectedSig, h.Signature()))
+		expectedTxRoot := ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+		bid, err := h.Message()
+		require.NoError(t, err)
+		bidHeader, err := bid.Header()
+		require.NoError(t, err)
+		withdrawalsRoot, err := bidHeader.TransactionsRoot()
+		require.NoError(t, err)
+		require.Equal(t, true, bytes.Equal(expectedTxRoot, withdrawalsRoot))
+		require.Equal(t, uint64(1), bidHeader.GasUsed())
+		// this matches the value in the testExampleHeaderResponse
+		bidStr := "652312848583266388373324160190187140051835877600158453279131187530910662656"
+		value, err := stringToUint256(bidStr)
+		require.NoError(t, err)
+		require.Equal(t, 0, value.Int.Cmp(primitives.WeiToBigInt(bid.Value())))
+		require.Equal(t, bidStr, primitives.WeiToBigInt(bid.Value()).String())
 	})
 	t.Run("capella", func(t *testing.T) {
 		hc := &http.Client{
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
 				require.Equal(t, expectedPath, r.URL.Path)
 				return &http.Response{
 					StatusCode: http.StatusOK,
@@ -230,16 +324,58 @@ func TestClient_GetHeader(t *testing.T) {
 		withdrawalsRoot, err := bidHeader.WithdrawalsRoot()
 		require.NoError(t, err)
 		require.Equal(t, true, bytes.Equal(expectedWithdrawalsRoot, withdrawalsRoot))
-		value, err := stringToUint256("652312848583266388373324160190187140051835877600158453279131187530910662656")
+		bidStr := "652312848583266388373324160190187140051835877600158453279131187530910662656"
+		value, err := stringToUint256(bidStr)
 		require.NoError(t, err)
-		require.Equal(t, fmt.Sprintf("%#x", value.SSZBytes()), fmt.Sprintf("%#x", bid.Value()))
-		bidValue := bytesutil.ReverseByteOrder(bid.Value())
-		require.DeepEqual(t, bidValue, value.Bytes())
-		require.DeepEqual(t, big.NewInt(0).SetBytes(bidValue), value.Int)
+		require.Equal(t, 0, value.Int.Cmp(primitives.WeiToBigInt(bid.Value())))
+		require.Equal(t, bidStr, primitives.WeiToBigInt(bid.Value()).String())
+	})
+	t.Run("capella ssz", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Accept"))
+				require.Equal(t, expectedPath, r.URL.Path)
+				epr := &ExecHeaderResponseCapella{}
+				require.NoError(t, json.Unmarshal([]byte(testExampleHeaderResponseCapella), epr))
+				pro, err := epr.ToProto()
+				require.NoError(t, err)
+				ssz, err := pro.MarshalSSZ()
+				require.NoError(t, err)
+				header := http.Header{}
+				header.Set(api.VersionHeader, "capella")
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Header:     header,
+					Body:       io.NopCloser(bytes.NewBuffer(ssz)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:         hc,
+			baseURL:    &url.URL{Host: "localhost:3500", Scheme: "http"},
+			sszEnabled: true,
+		}
+		h, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
+		require.NoError(t, err)
+		expectedWithdrawalsRoot := ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+		bid, err := h.Message()
+		require.NoError(t, err)
+		bidHeader, err := bid.Header()
+		require.NoError(t, err)
+		withdrawalsRoot, err := bidHeader.WithdrawalsRoot()
+		require.NoError(t, err)
+		require.Equal(t, true, bytes.Equal(expectedWithdrawalsRoot, withdrawalsRoot))
+		bidStr := "652312848583266388373324160190187140051835877600158453279131187530910662656"
+		value, err := stringToUint256(bidStr)
+		require.NoError(t, err)
+		require.Equal(t, 0, value.Int.Cmp(primitives.WeiToBigInt(bid.Value())))
+		require.Equal(t, bidStr, primitives.WeiToBigInt(bid.Value()).String())
 	})
 	t.Run("deneb", func(t *testing.T) {
 		hc := &http.Client{
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
 				require.Equal(t, expectedPath, r.URL.Path)
 				return &http.Response{
 					StatusCode: http.StatusOK,
@@ -262,14 +398,65 @@ func TestClient_GetHeader(t *testing.T) {
 		withdrawalsRoot, err := bidHeader.WithdrawalsRoot()
 		require.NoError(t, err)
 		require.Equal(t, true, bytes.Equal(expectedWithdrawalsRoot, withdrawalsRoot))
-		value, err := stringToUint256("652312848583266388373324160190187140051835877600158453279131187530910662656")
+
+		bidStr := "652312848583266388373324160190187140051835877600158453279131187530910662656"
+		value, err := stringToUint256(bidStr)
 		require.NoError(t, err)
-		require.Equal(t, fmt.Sprintf("%#x", value.SSZBytes()), fmt.Sprintf("%#x", bid.Value()))
-		bidValue := bytesutil.ReverseByteOrder(bid.Value())
-		require.DeepEqual(t, bidValue, value.Bytes())
-		require.DeepEqual(t, big.NewInt(0).SetBytes(bidValue), value.Int)
-		kcgCommitments, err := bid.BlobKzgCommitments()
+		require.Equal(t, 0, value.Int.Cmp(primitives.WeiToBigInt(bid.Value())))
+		require.Equal(t, bidStr, primitives.WeiToBigInt(bid.Value()).String())
+		dbid, ok := bid.(builderBidDeneb)
+		require.Equal(t, true, ok)
+		kcgCommitments := dbid.BlobKzgCommitments()
+		require.Equal(t, len(kcgCommitments) > 0, true)
+		for i := range kcgCommitments {
+			require.Equal(t, len(kcgCommitments[i]) == 48, true)
+		}
+	})
+	t.Run("deneb ssz", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Accept"))
+				require.Equal(t, expectedPath, r.URL.Path)
+				epr := &ExecHeaderResponseDeneb{}
+				require.NoError(t, json.Unmarshal([]byte(testExampleHeaderResponseDeneb), epr))
+				pro, err := epr.ToProto()
+				require.NoError(t, err)
+				ssz, err := pro.MarshalSSZ()
+				require.NoError(t, err)
+				header := http.Header{}
+				header.Set(api.VersionHeader, "deneb")
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Header:     header,
+					Body:       io.NopCloser(bytes.NewBuffer(ssz)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:         hc,
+			baseURL:    &url.URL{Host: "localhost:3500", Scheme: "http"},
+			sszEnabled: true,
+		}
+		h, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
 		require.NoError(t, err)
+		expectedWithdrawalsRoot := ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+		bid, err := h.Message()
+		require.NoError(t, err)
+		bidHeader, err := bid.Header()
+		require.NoError(t, err)
+		withdrawalsRoot, err := bidHeader.WithdrawalsRoot()
+		require.NoError(t, err)
+		require.Equal(t, true, bytes.Equal(expectedWithdrawalsRoot, withdrawalsRoot))
+
+		bidStr := "652312848583266388373324160190187140051835877600158453279131187530910662656"
+		value, err := stringToUint256(bidStr)
+		require.NoError(t, err)
+		require.Equal(t, 0, value.Int.Cmp(primitives.WeiToBigInt(bid.Value())))
+		require.Equal(t, bidStr, primitives.WeiToBigInt(bid.Value()).String())
+		dbid, ok := bid.(builderBidDeneb)
+		require.Equal(t, true, ok)
+		kcgCommitments := dbid.BlobKzgCommitments()
 		require.Equal(t, len(kcgCommitments) > 0, true)
 		for i := range kcgCommitments {
 			require.Equal(t, len(kcgCommitments[i]) == 48, true)
@@ -291,7 +478,107 @@ func TestClient_GetHeader(t *testing.T) {
 			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
 		}
 		_, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
-		require.ErrorContains(t, "could not extract proto message from header: too many blob commitments: 7", err)
+		require.ErrorContains(t, "could not convert ExecHeaderResponseDeneb to proto: too many blob commitments: 7", err)
+	})
+	t.Run("electra", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
+				require.Equal(t, expectedPath, r.URL.Path)
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body:       io.NopCloser(bytes.NewBufferString(testExampleHeaderResponseElectra)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+		h, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
+		require.NoError(t, err)
+		expectedWithdrawalsRoot := ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+		bid, err := h.Message()
+		require.NoError(t, err)
+		bidHeader, err := bid.Header()
+		require.NoError(t, err)
+		withdrawalsRoot, err := bidHeader.WithdrawalsRoot()
+		require.NoError(t, err)
+		require.Equal(t, true, bytes.Equal(expectedWithdrawalsRoot, withdrawalsRoot))
+
+		bidStr := "652312848583266388373324160190187140051835877600158453279131187530910662656"
+		value, err := stringToUint256(bidStr)
+		require.NoError(t, err)
+		require.Equal(t, 0, value.Int.Cmp(primitives.WeiToBigInt(bid.Value())))
+		require.Equal(t, bidStr, primitives.WeiToBigInt(bid.Value()).String())
+		ebid, ok := bid.(builderBidElectra)
+		require.Equal(t, true, ok)
+		kcgCommitments := ebid.BlobKzgCommitments()
+		require.Equal(t, len(kcgCommitments) > 0, true)
+		for i := range kcgCommitments {
+			require.Equal(t, len(kcgCommitments[i]) == 48, true)
+		}
+		requests := ebid.ExecutionRequests()
+		require.Equal(t, 1, len(requests.Deposits))
+		require.Equal(t, 1, len(requests.Withdrawals))
+		require.Equal(t, 1, len(requests.Consolidations))
+
+	})
+	t.Run("electra ssz", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Accept"))
+				require.Equal(t, expectedPath, r.URL.Path)
+				epr := &ExecHeaderResponseElectra{}
+				require.NoError(t, json.Unmarshal([]byte(testExampleHeaderResponseElectra), epr))
+				pro, err := epr.ToProto()
+				require.NoError(t, err)
+				ssz, err := pro.MarshalSSZ()
+				require.NoError(t, err)
+				header := http.Header{}
+				header.Set(api.VersionHeader, "electra")
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Header:     header,
+					Body:       io.NopCloser(bytes.NewBuffer(ssz)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:         hc,
+			baseURL:    &url.URL{Host: "localhost:3500", Scheme: "http"},
+			sszEnabled: true,
+		}
+		h, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
+		require.NoError(t, err)
+		expectedWithdrawalsRoot := ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+		bid, err := h.Message()
+		require.NoError(t, err)
+		bidHeader, err := bid.Header()
+		require.NoError(t, err)
+		withdrawalsRoot, err := bidHeader.WithdrawalsRoot()
+		require.NoError(t, err)
+		require.Equal(t, true, bytes.Equal(expectedWithdrawalsRoot, withdrawalsRoot))
+
+		bidStr := "652312848583266388373324160190187140051835877600158453279131187530910662656"
+		value, err := stringToUint256(bidStr)
+		require.NoError(t, err)
+		require.Equal(t, 0, value.Int.Cmp(primitives.WeiToBigInt(bid.Value())))
+		require.Equal(t, bidStr, primitives.WeiToBigInt(bid.Value()).String())
+		ebid, ok := bid.(builderBidElectra)
+		require.Equal(t, true, ok)
+		kcgCommitments := ebid.BlobKzgCommitments()
+		require.Equal(t, len(kcgCommitments) > 0, true)
+		for i := range kcgCommitments {
+			require.Equal(t, len(kcgCommitments[i]) == 48, true)
+		}
+		requests := ebid.ExecutionRequests()
+		require.Equal(t, 1, len(requests.Deposits))
+		require.Equal(t, 1, len(requests.Withdrawals))
+		require.Equal(t, 1, len(requests.Consolidations))
+
 	})
 	t.Run("unsupported version", func(t *testing.T) {
 		hc := &http.Client{
@@ -321,8 +608,8 @@ func TestSubmitBlindedBlock(t *testing.T) {
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
 				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
 				require.Equal(t, "bellatrix", r.Header.Get("Eth-Consensus-Version"))
-				require.Equal(t, "application/json", r.Header.Get("Content-Type"))
-				require.Equal(t, "application/json", r.Header.Get("Accept"))
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
 				return &http.Response{
 					StatusCode: http.StatusOK,
 					Body:       io.NopCloser(bytes.NewBufferString(testExampleExecutionPayload)),
@@ -344,13 +631,53 @@ func TestSubmitBlindedBlock(t *testing.T) {
 		require.Equal(t, fmt.Sprintf("%#x", bfpg.SSZBytes()), fmt.Sprintf("%#x", ep.BaseFeePerGas()))
 		require.Equal(t, uint64(1), ep.GasLimit())
 	})
+	t.Run("bellatrix ssz", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
+				require.Equal(t, "bellatrix", r.Header.Get(api.VersionHeader))
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Accept"))
+				epr := &ExecutionPayloadResponse{}
+				require.NoError(t, json.Unmarshal([]byte(testExampleExecutionPayload), epr))
+				ep := &ExecutionPayload{}
+				require.NoError(t, json.Unmarshal(epr.Data, ep))
+				pro, err := ep.ToProto()
+				require.NoError(t, err)
+				ssz, err := pro.MarshalSSZ()
+				require.NoError(t, err)
+				header := http.Header{}
+				header.Set(api.VersionHeader, "bellatrix")
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Header:     header,
+					Body:       io.NopCloser(bytes.NewBuffer(ssz)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:         hc,
+			baseURL:    &url.URL{Host: "localhost:3500", Scheme: "http"},
+			sszEnabled: true,
+		}
+		sbbb, err := blocks.NewSignedBeaconBlock(testSignedBlindedBeaconBlockBellatrix(t))
+		require.NoError(t, err)
+		ep, _, err := c.SubmitBlindedBlock(ctx, sbbb)
+		require.NoError(t, err)
+		require.Equal(t, true, bytes.Equal(ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"), ep.ParentHash()))
+		bfpg, err := stringToUint256("452312848583266388373324160190187140051835877600158453279131187530910662656")
+		require.NoError(t, err)
+		require.Equal(t, fmt.Sprintf("%#x", bfpg.SSZBytes()), fmt.Sprintf("%#x", ep.BaseFeePerGas()))
+		require.Equal(t, uint64(1), ep.GasLimit())
+	})
 	t.Run("capella", func(t *testing.T) {
 		hc := &http.Client{
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
 				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
-				require.Equal(t, "capella", r.Header.Get("Eth-Consensus-Version"))
-				require.Equal(t, "application/json", r.Header.Get("Content-Type"))
-				require.Equal(t, "application/json", r.Header.Get("Accept"))
+				require.Equal(t, "capella", r.Header.Get(api.VersionHeader))
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
 				return &http.Response{
 					StatusCode: http.StatusOK,
 					Body:       io.NopCloser(bytes.NewBufferString(testExampleExecutionPayloadCapella)),
@@ -370,7 +697,49 @@ func TestSubmitBlindedBlock(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, 1, len(withdrawals))
 		assert.Equal(t, uint64(1), withdrawals[0].Index)
-		assert.Equal(t, types.ValidatorIndex(1), withdrawals[0].ValidatorIndex)
+		assert.Equal(t, primitives.ValidatorIndex(1), withdrawals[0].ValidatorIndex)
+		assert.DeepEqual(t, ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943"), withdrawals[0].Address)
+		assert.Equal(t, uint64(1), withdrawals[0].Amount)
+	})
+	t.Run("capella ssz", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
+				require.Equal(t, "capella", r.Header.Get(api.VersionHeader))
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Accept"))
+				epr := &ExecutionPayloadResponse{}
+				require.NoError(t, json.Unmarshal([]byte(testExampleExecutionPayloadCapella), epr))
+				ep := &ExecutionPayloadCapella{}
+				require.NoError(t, json.Unmarshal(epr.Data, ep))
+				pro, err := ep.ToProto()
+				require.NoError(t, err)
+				ssz, err := pro.MarshalSSZ()
+				require.NoError(t, err)
+				header := http.Header{}
+				header.Set(api.VersionHeader, "capella")
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Header:     header,
+					Body:       io.NopCloser(bytes.NewBuffer(ssz)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:         hc,
+			baseURL:    &url.URL{Host: "localhost:3500", Scheme: "http"},
+			sszEnabled: true,
+		}
+		sbb, err := blocks.NewSignedBeaconBlock(testSignedBlindedBeaconBlockCapella(t))
+		require.NoError(t, err)
+		ep, _, err := c.SubmitBlindedBlock(ctx, sbb)
+		require.NoError(t, err)
+		withdrawals, err := ep.Withdrawals()
+		require.NoError(t, err)
+		require.Equal(t, 1, len(withdrawals))
+		assert.Equal(t, uint64(1), withdrawals[0].Index)
+		assert.Equal(t, primitives.ValidatorIndex(1), withdrawals[0].ValidatorIndex)
 		assert.DeepEqual(t, ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943"), withdrawals[0].Address)
 		assert.Equal(t, uint64(1), withdrawals[0].Amount)
 	})
@@ -379,9 +748,9 @@ func TestSubmitBlindedBlock(t *testing.T) {
 		hc := &http.Client{
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
 				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
-				require.Equal(t, "deneb", r.Header.Get("Eth-Consensus-Version"))
-				require.Equal(t, "application/json", r.Header.Get("Content-Type"))
-				require.Equal(t, "application/json", r.Header.Get("Accept"))
+				require.Equal(t, "deneb", r.Header.Get(api.VersionHeader))
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
 				var req structs.SignedBlindedBeaconBlockDeneb
 				err := json.NewDecoder(r.Body).Decode(&req)
 				require.NoError(t, err)
@@ -409,7 +778,141 @@ func TestSubmitBlindedBlock(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, 1, len(withdrawals))
 		assert.Equal(t, uint64(1), withdrawals[0].Index)
-		assert.Equal(t, types.ValidatorIndex(1), withdrawals[0].ValidatorIndex)
+		assert.Equal(t, primitives.ValidatorIndex(1), withdrawals[0].ValidatorIndex)
+		assert.DeepEqual(t, ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943"), withdrawals[0].Address)
+		assert.Equal(t, uint64(1), withdrawals[0].Amount)
+		require.NotNil(t, blobBundle)
+	})
+	t.Run("deneb ssz", func(t *testing.T) {
+		test := testSignedBlindedBeaconBlockDeneb(t)
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
+				require.Equal(t, "deneb", r.Header.Get(api.VersionHeader))
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Accept"))
+				epr := &ExecPayloadResponseDeneb{}
+				require.NoError(t, json.Unmarshal([]byte(testExampleExecutionPayloadDeneb), epr))
+				pro, blob, err := epr.ToProto()
+				require.NoError(t, err)
+				combined := &v1.ExecutionPayloadDenebAndBlobsBundle{
+					Payload:     pro,
+					BlobsBundle: blob,
+				}
+				ssz, err := combined.MarshalSSZ()
+				require.NoError(t, err)
+				header := http.Header{}
+				header.Set(api.VersionHeader, "deneb")
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Header:     header,
+					Body:       io.NopCloser(bytes.NewBuffer(ssz)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:         hc,
+			baseURL:    &url.URL{Host: "localhost:3500", Scheme: "http"},
+			sszEnabled: true,
+		}
+		sbb, err := blocks.NewSignedBeaconBlock(test)
+		require.NoError(t, err)
+
+		ep, blobBundle, err := c.SubmitBlindedBlock(ctx, sbb)
+		require.NoError(t, err)
+		withdrawals, err := ep.Withdrawals()
+		require.NoError(t, err)
+		require.Equal(t, 1, len(withdrawals))
+		assert.Equal(t, uint64(1), withdrawals[0].Index)
+		assert.Equal(t, primitives.ValidatorIndex(1), withdrawals[0].ValidatorIndex)
+		assert.DeepEqual(t, ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943"), withdrawals[0].Address)
+		assert.Equal(t, uint64(1), withdrawals[0].Amount)
+		require.NotNil(t, blobBundle)
+	})
+	t.Run("electra", func(t *testing.T) {
+		test := testSignedBlindedBeaconBlockElectra(t)
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
+				require.Equal(t, "electra", r.Header.Get(api.VersionHeader))
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
+				var req structs.SignedBlindedBeaconBlockElectra
+				err := json.NewDecoder(r.Body).Decode(&req)
+				require.NoError(t, err)
+				block, err := req.ToConsensus()
+				require.NoError(t, err)
+				require.DeepEqual(t, block, test)
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body:       io.NopCloser(bytes.NewBufferString(testExampleExecutionPayloadDeneb)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+
+		sbb, err := blocks.NewSignedBeaconBlock(test)
+		require.NoError(t, err)
+
+		ep, blobBundle, err := c.SubmitBlindedBlock(ctx, sbb)
+		require.NoError(t, err)
+		withdrawals, err := ep.Withdrawals()
+		require.NoError(t, err)
+		require.Equal(t, 1, len(withdrawals))
+		assert.Equal(t, uint64(1), withdrawals[0].Index)
+		assert.Equal(t, primitives.ValidatorIndex(1), withdrawals[0].ValidatorIndex)
+		assert.DeepEqual(t, ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943"), withdrawals[0].Address)
+		assert.Equal(t, uint64(1), withdrawals[0].Amount)
+		require.NotNil(t, blobBundle)
+	})
+	t.Run("electra ssz", func(t *testing.T) {
+		test := testSignedBlindedBeaconBlockElectra(t)
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
+				require.Equal(t, "electra", r.Header.Get(api.VersionHeader))
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Accept"))
+				epr := &ExecPayloadResponseDeneb{}
+				require.NoError(t, json.Unmarshal([]byte(testExampleExecutionPayloadDeneb), epr))
+				pro, blob, err := epr.ToProto()
+				require.NoError(t, err)
+				combined := &v1.ExecutionPayloadDenebAndBlobsBundle{
+					Payload:     pro,
+					BlobsBundle: blob,
+				}
+				ssz, err := combined.MarshalSSZ()
+				require.NoError(t, err)
+				header := http.Header{}
+				header.Set(api.VersionHeader, "electra")
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Header:     header,
+					Body:       io.NopCloser(bytes.NewBuffer(ssz)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:         hc,
+			baseURL:    &url.URL{Host: "localhost:3500", Scheme: "http"},
+			sszEnabled: true,
+		}
+		sbb, err := blocks.NewSignedBeaconBlock(test)
+		require.NoError(t, err)
+
+		ep, blobBundle, err := c.SubmitBlindedBlock(ctx, sbb)
+		require.NoError(t, err)
+		withdrawals, err := ep.Withdrawals()
+		require.NoError(t, err)
+		require.Equal(t, 1, len(withdrawals))
+		assert.Equal(t, uint64(1), withdrawals[0].Index)
+		assert.Equal(t, primitives.ValidatorIndex(1), withdrawals[0].ValidatorIndex)
 		assert.DeepEqual(t, ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943"), withdrawals[0].Address)
 		assert.Equal(t, uint64(1), withdrawals[0].Amount)
 		require.NotNil(t, blobBundle)
@@ -432,7 +935,7 @@ func TestSubmitBlindedBlock(t *testing.T) {
 		sbbb, err := blocks.NewSignedBeaconBlock(testSignedBlindedBeaconBlockBellatrix(t))
 		require.NoError(t, err)
 		_, _, err = c.SubmitBlindedBlock(ctx, sbbb)
-		require.ErrorContains(t, "not a bellatrix payload", err)
+		require.ErrorIs(t, err, errResponseVersionMismatch)
 	})
 	t.Run("not blinded", func(t *testing.T) {
 		sbb, err := blocks.NewSignedBeaconBlock(&eth.SignedBeaconBlockBellatrix{Block: &eth.BeaconBlockBellatrix{Body: &eth.BeaconBlockBodyBellatrix{ExecutionPayload: &v1.ExecutionPayload{}}}})
@@ -540,7 +1043,13 @@ func testSignedBlindedBeaconBlockBellatrix(t *testing.T) *eth.SignedBlindedBeaco
 				},
 				Deposits: []*eth.Deposit{
 					{
-						Proof: [][]byte{ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")},
+						Proof: func() [][]byte {
+							b := make([][]byte, 33)
+							for i := range b {
+								b[i] = ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+							}
+							return b
+						}(),
 						Data: &eth.Deposit_Data{
 							PublicKey:             ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"),
 							WithdrawalCredentials: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
@@ -559,8 +1068,8 @@ func testSignedBlindedBeaconBlockBellatrix(t *testing.T) *eth.SignedBlindedBeaco
 					},
 				},
 				SyncAggregate: &eth.SyncAggregate{
-					SyncCommitteeSignature: make([]byte, 48),
-					SyncCommitteeBits:      bitfield.Bitvector512{0x01},
+					SyncCommitteeSignature: make([]byte, 96),
+					SyncCommitteeBits:      make(bitfield.Bitvector512, 64),
 				},
 				ExecutionPayloadHeader: &v1.ExecutionPayloadHeader{
 					ParentHash:       ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
@@ -574,7 +1083,7 @@ func testSignedBlindedBeaconBlockBellatrix(t *testing.T) *eth.SignedBlindedBeaco
 					GasUsed:          1,
 					Timestamp:        1,
 					ExtraData:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
-					BaseFeePerGas:    []byte(strconv.FormatUint(1, 10)),
+					BaseFeePerGas:    ezDecode(t, "0x4523128485832663883733241601901871400518358776001584532791311875"),
 					BlockHash:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
 					TransactionsRoot: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
 				},
@@ -682,7 +1191,13 @@ func testSignedBlindedBeaconBlockCapella(t *testing.T) *eth.SignedBlindedBeaconB
 				},
 				Deposits: []*eth.Deposit{
 					{
-						Proof: [][]byte{ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")},
+						Proof: func() [][]byte {
+							b := make([][]byte, 33)
+							for i := range b {
+								b[i] = ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+							}
+							return b
+						}(),
 						Data: &eth.Deposit_Data{
 							PublicKey:             ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"),
 							WithdrawalCredentials: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
@@ -701,8 +1216,8 @@ func testSignedBlindedBeaconBlockCapella(t *testing.T) *eth.SignedBlindedBeaconB
 					},
 				},
 				SyncAggregate: &eth.SyncAggregate{
-					SyncCommitteeSignature: make([]byte, 48),
-					SyncCommitteeBits:      bitfield.Bitvector512{0x01},
+					SyncCommitteeSignature: make([]byte, 96),
+					SyncCommitteeBits:      make(bitfield.Bitvector512, 64),
 				},
 				ExecutionPayloadHeader: &v1.ExecutionPayloadHeaderCapella{
 					ParentHash:       ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
@@ -716,7 +1231,7 @@ func testSignedBlindedBeaconBlockCapella(t *testing.T) *eth.SignedBlindedBeaconB
 					GasUsed:          1,
 					Timestamp:        1,
 					ExtraData:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
-					BaseFeePerGas:    []byte(strconv.FormatUint(1, 10)),
+					BaseFeePerGas:    ezDecode(t, "0x4523128485832663883733241601901871400518358776001584532791311875"),
 					BlockHash:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
 					TransactionsRoot: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
 					WithdrawalsRoot:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
@@ -829,7 +1344,13 @@ func testSignedBlindedBeaconBlockDeneb(t *testing.T) *eth.SignedBlindedBeaconBlo
 				},
 				Deposits: []*eth.Deposit{
 					{
-						Proof: [][]byte{ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")},
+						Proof: func() [][]byte {
+							b := make([][]byte, 33)
+							for i := range b {
+								b[i] = ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+							}
+							return b
+						}(),
 						Data: &eth.Deposit_Data{
 							PublicKey:             ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"),
 							WithdrawalCredentials: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
@@ -876,6 +1397,163 @@ func testSignedBlindedBeaconBlockDeneb(t *testing.T) *eth.SignedBlindedBeaconBlo
 	}
 }
 
+func testSignedBlindedBeaconBlockElectra(t *testing.T) *eth.SignedBlindedBeaconBlockElectra {
+	basebytes, err := bytesutil.Uint256ToSSZBytes("14074904626401341155369551180448584754667373453244490859944217516317499064576")
+	if err != nil {
+		log.Error(err)
+	}
+	return &eth.SignedBlindedBeaconBlockElectra{
+		Message: &eth.BlindedBeaconBlockElectra{
+			Slot:          1,
+			ProposerIndex: 1,
+			ParentRoot:    ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+			StateRoot:     ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+			Body: &eth.BlindedBeaconBlockBodyElectra{
+				RandaoReveal: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+				Eth1Data: &eth.Eth1Data{
+					DepositRoot:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					DepositCount: 1,
+					BlockHash:    ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+				},
+				Graffiti: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+				ProposerSlashings: []*eth.ProposerSlashing{
+					{
+						Header_1: &eth.SignedBeaconBlockHeader{
+							Header: &eth.BeaconBlockHeader{
+								Slot:          1,
+								ProposerIndex: 1,
+								ParentRoot:    ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								StateRoot:     ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								BodyRoot:      ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							},
+							Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+						},
+						Header_2: &eth.SignedBeaconBlockHeader{
+							Header: &eth.BeaconBlockHeader{
+								Slot:          1,
+								ProposerIndex: 1,
+								ParentRoot:    ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								StateRoot:     ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								BodyRoot:      ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							},
+							Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+						},
+					},
+				},
+				AttesterSlashings: []*eth.AttesterSlashingElectra{
+					{
+						Attestation_1: &eth.IndexedAttestationElectra{
+							AttestingIndices: []uint64{1},
+							Data: &eth.AttestationData{
+								Slot:            1,
+								CommitteeIndex:  1,
+								BeaconBlockRoot: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								Source: &eth.Checkpoint{
+									Epoch: 1,
+									Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								},
+								Target: &eth.Checkpoint{
+									Epoch: 1,
+									Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								},
+							},
+							Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+						},
+						Attestation_2: &eth.IndexedAttestationElectra{
+							AttestingIndices: []uint64{1},
+							Data: &eth.AttestationData{
+								Slot:            1,
+								CommitteeIndex:  1,
+								BeaconBlockRoot: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								Source: &eth.Checkpoint{
+									Epoch: 1,
+									Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								},
+								Target: &eth.Checkpoint{
+									Epoch: 1,
+									Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								},
+							},
+							Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+						},
+					},
+				},
+				Attestations: []*eth.AttestationElectra{
+					{
+						AggregationBits: bitfield.Bitlist{0x01},
+						Data: &eth.AttestationData{
+							Slot:            1,
+							CommitteeIndex:  1,
+							BeaconBlockRoot: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							Source: &eth.Checkpoint{
+								Epoch: 1,
+								Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							},
+							Target: &eth.Checkpoint{
+								Epoch: 1,
+								Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							},
+						},
+						CommitteeBits: make(bitfield.Bitvector64, 8),
+						Signature:     ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+					},
+				},
+				Deposits: []*eth.Deposit{
+					{
+						Proof: func() [][]byte {
+							b := make([][]byte, 33)
+							for i := range b {
+								b[i] = ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+							}
+							return b
+						}(),
+						Data: &eth.Deposit_Data{
+							PublicKey:             ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"),
+							WithdrawalCredentials: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							Amount:                1,
+							Signature:             ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+						},
+					},
+				},
+				VoluntaryExits: []*eth.SignedVoluntaryExit{
+					{
+						Exit: &eth.VoluntaryExit{
+							Epoch:          1,
+							ValidatorIndex: 1,
+						},
+						Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+					},
+				},
+				SyncAggregate: &eth.SyncAggregate{
+					SyncCommitteeSignature: make([]byte, 96),
+					SyncCommitteeBits:      ezDecode(t, "0x6451e9f951ebf05edc01de67e593484b672877054f055903ff0df1a1a945cf30ca26bb4d4b154f94a1bc776bcf5d0efb3603e1f9b8ee2499ccdcfe2a18cef458"),
+				},
+				ExecutionRequests: &v1.ExecutionRequests{},
+				ExecutionPayloadHeader: &v1.ExecutionPayloadHeaderDeneb{
+					ParentHash:       ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					FeeRecipient:     ezDecode(t, "0xabcf8e0d4e9587369b2301d0790347320302cc09"),
+					StateRoot:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					ReceiptsRoot:     ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					LogsBloom:        ezDecode(t, "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"),
+					PrevRandao:       ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					BlockNumber:      1,
+					GasLimit:         1,
+					GasUsed:          1,
+					Timestamp:        1,
+					ExtraData:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					BaseFeePerGas:    basebytes,
+					BlockHash:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					TransactionsRoot: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					WithdrawalsRoot:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					BlobGasUsed:      1,
+					ExcessBlobGas:    2,
+				},
+			},
+		},
+		Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+	}
+}
+
 func TestRequestLogger(t *testing.T) {
 	wo := WithObserver(&requestLogger{})
 	c, err := NewClient("localhost:3500", wo)

api/client/builder/errors.go

@@ -15,3 +15,9 @@ var ErrBadRequest = errors.Wrap(ErrNotOK, "recv 400 BadRequest response from API
 // ErrNoContent specifically means that a '204 - No Content' response was received from the API.
 // Typically, a 204 is a success but in this case for the Header API means No header is available
 var ErrNoContent = errors.New("recv 204 no content response from API, No header is available")
+
+// ErrUnsupportedMediaType specifically means that a '415 - Unsupported Media Type' was received from the API.
+var ErrUnsupportedMediaType = errors.Wrap(ErrNotOK, "The media type in \"Content-Type\" header is unsupported, and the request has been rejected. This occurs when a HTTP request supplies a payload in a content-type that the server is not able to handle.")
+
+// ErrNotAcceptable specifically means that a '406 - Not Acceptable' was received from the API.
+var ErrNotAcceptable = errors.Wrap(ErrNotOK, "The accept header value is not acceptable")

api/client/builder/testing/BUILD.bazel

@@ -3,7 +3,7 @@ load("@prysm//tools/go:def.bzl", "go_library")
 go_library(
     name = "go_default_library",
     srcs = ["mock.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/builder/testing",
+    importpath = "github.com/OffchainLabs/prysm/v6/api/client/builder/testing",
     visibility = ["//visibility:public"],
     deps = [
         "//api/client/builder:go_default_library",

api/client/builder/testing/mock.go

@@ -3,12 +3,12 @@ package testing
 import (
 	"context"
 
-	"github.com/prysmaticlabs/prysm/v5/api/client/builder"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/api/client/builder"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	v1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
+	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 )
 
 // MockClient is a mock implementation of BuilderClient.

api/client/builder/types.go

@@ -5,15 +5,22 @@ import (
 	"fmt"
 	"math/big"
 	"strconv"
+	"strings"
 
+	"github.com/OffchainLabs/prysm/v6/api/server"
+	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
+	"github.com/OffchainLabs/prysm/v6/config/params"
+	consensusblocks "github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	types "github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	"github.com/OffchainLabs/prysm/v6/math"
+	v1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
+	eth "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/runtime/version"
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
-	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
-	types "github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	"github.com/prysmaticlabs/prysm/v5/math"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
+	"google.golang.org/protobuf/proto"
 )
 
 var errInvalidUint256 = errors.New("invalid Uint256")
@@ -44,6 +51,9 @@ func sszBytesToUint256(b []byte) (Uint256, error) {
 
 // SSZBytes creates an ssz-style (little-endian byte slice) representation of the Uint256.
 func (s Uint256) SSZBytes() []byte {
+	if s.Int == nil {
+		s.Int = big.NewInt(0)
+	}
 	if !math.IsValidUint256(s.Int) {
 		return []byte{}
 	}
@@ -91,6 +101,9 @@ func (s Uint256) MarshalJSON() ([]byte, error) {
 
 // MarshalText returns a text byte representation of Uint256.
 func (s Uint256) MarshalText() ([]byte, error) {
+	if s.Int == nil {
+		s.Int = big.NewInt(0)
+	}
 	if !math.IsValidUint256(s.Int) {
 		return nil, errors.Wrapf(errInvalidUint256, "value=%s", s.Int)
 	}
@@ -146,6 +159,8 @@ func (bb *BuilderBid) ToProto() (*eth.BuilderBid, error) {
 	}
 	return &eth.BuilderBid{
 		Header: header,
+		// Note that SSZBytes() reverses byte order for the little-endian representation.
+		// Uint256.Bytes() is big-endian, SSZBytes takes this value and reverses it.
 		Value:  bb.Value.SSZBytes(),
 		Pubkey: bb.Pubkey,
 	}, nil
@@ -265,6 +280,11 @@ func (r *ExecPayloadResponse) ToProto() (*v1.ExecutionPayload, error) {
 	return r.Data.ToProto()
 }
 
+func (r *ExecutionPayload) PayloadProto() (proto.Message, error) {
+	pb, err := r.ToProto()
+	return pb, err
+}
+
 // ToProto returns a ExecutionPayload Proto
 func (p *ExecutionPayload) ToProto() (*v1.ExecutionPayload, error) {
 	txs := make([][]byte, len(p.Transactions))
@@ -398,7 +418,8 @@ func FromProtoDeneb(payload *v1.ExecutionPayloadDeneb) (ExecutionPayloadDeneb, e
 
 // ExecHeaderResponseCapella is the response of builder API /eth/v1/builder/header/{slot}/{parent_hash}/{pubkey} for Capella.
 type ExecHeaderResponseCapella struct {
-	Data struct {
+	Version string `json:"version"`
+	Data    struct {
 		Signature hexutil.Bytes      `json:"signature"`
 		Message   *BuilderBidCapella `json:"message"`
 	} `json:"data"`
@@ -424,6 +445,8 @@ func (bb *BuilderBidCapella) ToProto() (*eth.BuilderBidCapella, error) {
 	}
 	return &eth.BuilderBidCapella{
 		Header: header,
+		// Note that SSZBytes() reverses byte order for the little-endian representation.
+		// Uint256.Bytes() is big-endian, SSZBytes takes this value and reverses it.
 		Value:  bytesutil.SafeCopyBytes(bb.Value.SSZBytes()),
 		Pubkey: bytesutil.SafeCopyBytes(bb.Pubkey),
 	}, nil
@@ -523,6 +546,50 @@ type ExecPayloadResponseCapella struct {
 	Data    ExecutionPayloadCapella `json:"data"`
 }
 
+// ExecutionPayloadResponse allows for unmarshaling just the Version field of the payload.
+// This allows it to return different ExecutionPayload types based on the version field.
+type ExecutionPayloadResponse struct {
+	Version string          `json:"version"`
+	Data    json.RawMessage `json:"data"`
+}
+
+// ParsedPayload can retrieve the underlying protobuf message for the given execution payload response.
+type ParsedPayload interface {
+	PayloadProto() (proto.Message, error)
+}
+
+// BlobBundler can retrieve the underlying blob bundle protobuf message for the given execution payload response.
+type BlobBundler interface {
+	BundleProto() (*v1.BlobsBundle, error)
+}
+
+// ParsedExecutionRequests can retrieve the underlying execution requests for the given execution payload response.
+type ParsedExecutionRequests interface {
+	ExecutionRequestsProto() (*v1.ExecutionRequests, error)
+}
+
+func (r *ExecutionPayloadResponse) ParsePayload() (ParsedPayload, error) {
+	var toProto ParsedPayload
+	v, err := version.FromString(strings.ToLower(r.Version))
+	if err != nil {
+		return nil, errors.Wrap(err, fmt.Sprintf("unsupported version %s", strings.ToLower(r.Version)))
+	}
+	if v >= version.Deneb {
+		toProto = &ExecutionPayloadDenebAndBlobsBundle{}
+	} else if v >= version.Capella {
+		toProto = &ExecutionPayloadCapella{}
+	} else if v >= version.Bellatrix {
+		toProto = &ExecutionPayload{}
+	} else {
+		return nil, fmt.Errorf("unsupported version %s", strings.ToLower(r.Version))
+	}
+
+	if err := json.Unmarshal(r.Data, toProto); err != nil {
+		return nil, errors.Wrap(err, "failed to unmarshal the response .Data field with the stated version schema")
+	}
+	return toProto, nil
+}
+
 // ExecutionPayloadCapella is a field of ExecPayloadResponseCapella.
 type ExecutionPayloadCapella struct {
 	ParentHash    hexutil.Bytes   `json:"parent_hash"`
@@ -547,6 +614,11 @@ func (r *ExecPayloadResponseCapella) ToProto() (*v1.ExecutionPayloadCapella, err
 	return r.Data.ToProto()
 }
 
+func (p *ExecutionPayloadCapella) PayloadProto() (proto.Message, error) {
+	pb, err := p.ToProto()
+	return pb, err
+}
+
 // ToProto returns a ExecutionPayloadCapella Proto.
 func (p *ExecutionPayloadCapella) ToProto() (*v1.ExecutionPayloadCapella, error) {
 	txs := make([][]byte, len(p.Transactions))
@@ -884,7 +956,8 @@ func (ch *BLSToExecutionChange) MarshalJSON() ([]byte, error) {
 
 // ExecHeaderResponseDeneb is the header response for builder API /eth/v1/builder/header/{slot}/{parent_hash}/{pubkey}.
 type ExecHeaderResponseDeneb struct {
-	Data struct {
+	Version string `json:"version"`
+	Data    struct {
 		Signature hexutil.Bytes    `json:"signature"`
 		Message   *BuilderBidDeneb `json:"message"`
 	} `json:"data"`
@@ -908,7 +981,7 @@ func (bb *BuilderBidDeneb) ToProto() (*eth.BuilderBidDeneb, error) {
 	if err != nil {
 		return nil, err
 	}
-	if len(bb.BlobKzgCommitments) > fieldparams.MaxBlobsPerBlock {
+	if len(bb.BlobKzgCommitments) > params.BeaconConfig().DeprecatedMaxBlobsPerBlock {
 		return nil, fmt.Errorf("too many blob commitments: %d", len(bb.BlobKzgCommitments))
 	}
 	kzgCommitments := make([][]byte, len(bb.BlobKzgCommitments))
@@ -921,8 +994,10 @@ func (bb *BuilderBidDeneb) ToProto() (*eth.BuilderBidDeneb, error) {
 	return &eth.BuilderBidDeneb{
 		Header:             header,
 		BlobKzgCommitments: kzgCommitments,
-		Value:              bytesutil.SafeCopyBytes(bb.Value.SSZBytes()),
-		Pubkey:             bytesutil.SafeCopyBytes(bb.Pubkey),
+		// Note that SSZBytes() reverses byte order for the little-endian representation.
+		// Uint256.Bytes() is big-endian, SSZBytes takes this value and reverses it.
+		Value:  bytesutil.SafeCopyBytes(bb.Value.SSZBytes()),
+		Pubkey: bytesutil.SafeCopyBytes(bb.Pubkey),
 	}, nil
 }
 
@@ -1128,6 +1203,12 @@ func (r *ExecPayloadResponseDeneb) ToProto() (*v1.ExecutionPayloadDeneb, *v1.Blo
 	if r.Data == nil {
 		return nil, nil, errors.New("data field in response is empty")
 	}
+	if r.Data.ExecutionPayload == nil {
+		return nil, nil, errors.Wrap(consensusblocks.ErrNilObject, "nil execution payload")
+	}
+	if r.Data.BlobsBundle == nil {
+		return nil, nil, errors.Wrap(consensusblocks.ErrNilObject, "nil blobs bundle")
+	}
 	payload, err := r.Data.ExecutionPayload.ToProto()
 	if err != nil {
 		return nil, nil, err
@@ -1139,8 +1220,26 @@ func (r *ExecPayloadResponseDeneb) ToProto() (*v1.ExecutionPayloadDeneb, *v1.Blo
 	return payload, bundle, nil
 }
 
+func (r *ExecutionPayloadDenebAndBlobsBundle) PayloadProto() (proto.Message, error) {
+	if r.ExecutionPayload == nil {
+		return nil, errors.Wrap(consensusblocks.ErrNilObject, "nil execution payload in combined deneb payload")
+	}
+	pb, err := r.ExecutionPayload.ToProto()
+	return pb, err
+}
+
+func (r *ExecutionPayloadDenebAndBlobsBundle) BundleProto() (*v1.BlobsBundle, error) {
+	if r.BlobsBundle == nil {
+		return nil, errors.Wrap(consensusblocks.ErrNilObject, "nil blobs bundle")
+	}
+	return r.BlobsBundle.ToProto()
+}
+
 // ToProto returns the ExecutionPayloadDeneb Proto.
 func (p *ExecutionPayloadDeneb) ToProto() (*v1.ExecutionPayloadDeneb, error) {
+	if p == nil {
+		return nil, errors.Wrap(consensusblocks.ErrNilObject, "nil execution payload")
+	}
 	txs := make([][]byte, len(p.Transactions))
 	for i := range p.Transactions {
 		txs[i] = bytesutil.SafeCopyBytes(p.Transactions[i])
@@ -1175,6 +1274,208 @@ func (p *ExecutionPayloadDeneb) ToProto() (*v1.ExecutionPayloadDeneb, error) {
 	}, nil
 }
 
+// ExecHeaderResponseElectra is the header response for builder API /eth/v1/builder/header/{slot}/{parent_hash}/{pubkey}.
+type ExecHeaderResponseElectra struct {
+	Version string `json:"version"`
+	Data    struct {
+		Signature hexutil.Bytes      `json:"signature"`
+		Message   *BuilderBidElectra `json:"message"`
+	} `json:"data"`
+}
+
+// ToProto creates a SignedBuilderBidElectra Proto from ExecHeaderResponseElectra.
+func (ehr *ExecHeaderResponseElectra) ToProto() (*eth.SignedBuilderBidElectra, error) {
+	bb, err := ehr.Data.Message.ToProto()
+	if err != nil {
+		return nil, err
+	}
+	return &eth.SignedBuilderBidElectra{
+		Message:   bb,
+		Signature: bytesutil.SafeCopyBytes(ehr.Data.Signature),
+	}, nil
+}
+
+// ToProto creates a BuilderBidElectra Proto from BuilderBidElectra.
+func (bb *BuilderBidElectra) ToProto() (*eth.BuilderBidElectra, error) {
+	header, err := bb.Header.ToProto()
+	if err != nil {
+		return nil, err
+	}
+	if len(bb.BlobKzgCommitments) > params.BeaconConfig().MaxBlobsPerBlockByVersion(version.Electra) {
+		return nil, fmt.Errorf("blob commitment count %d exceeds the maximum %d", len(bb.BlobKzgCommitments), params.BeaconConfig().MaxBlobsPerBlockByVersion(version.Electra))
+	}
+	kzgCommitments := make([][]byte, len(bb.BlobKzgCommitments))
+	for i, commit := range bb.BlobKzgCommitments {
+		if len(commit) != fieldparams.BLSPubkeyLength {
+			return nil, fmt.Errorf("commitment length %d is not %d", len(commit), fieldparams.BLSPubkeyLength)
+		}
+		kzgCommitments[i] = bytesutil.SafeCopyBytes(commit)
+	}
+	// post electra execution requests should not be nil, if no requests exist use an empty request
+	if bb.ExecutionRequests == nil {
+		return nil, errors.New("bid contains nil execution requests")
+	}
+	executionRequests, err := bb.ExecutionRequests.ToProto()
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to convert ExecutionRequests")
+	}
+	return &eth.BuilderBidElectra{
+		Header:             header,
+		BlobKzgCommitments: kzgCommitments,
+		ExecutionRequests:  executionRequests,
+		// Note that SSZBytes() reverses byte order for the little-endian representation.
+		// Uint256.Bytes() is big-endian, SSZBytes takes this value and reverses it.
+		Value:  bytesutil.SafeCopyBytes(bb.Value.SSZBytes()),
+		Pubkey: bytesutil.SafeCopyBytes(bb.Pubkey),
+	}, nil
+}
+
+// ExecutionRequestsV1 is a wrapper for different execution requests
+type ExecutionRequestsV1 struct {
+	Deposits       []*DepositRequestV1       `json:"deposits"`
+	Withdrawals    []*WithdrawalRequestV1    `json:"withdrawals"`
+	Consolidations []*ConsolidationRequestV1 `json:"consolidations"`
+}
+
+func (er *ExecutionRequestsV1) ToProto() (*v1.ExecutionRequests, error) {
+	if uint64(len(er.Deposits)) > params.BeaconConfig().MaxDepositRequestsPerPayload {
+		return nil, fmt.Errorf("deposit requests count %d exceeds the maximum %d", len(er.Deposits), params.BeaconConfig().MaxDepositRequestsPerPayload)
+	}
+	deposits := make([]*v1.DepositRequest, len(er.Deposits))
+	for i, dep := range er.Deposits {
+		d, err := dep.ToProto()
+		if err != nil {
+			return nil, err
+		}
+		deposits[i] = d
+	}
+	if uint64(len(er.Withdrawals)) > params.BeaconConfig().MaxWithdrawalRequestsPerPayload {
+		return nil, fmt.Errorf("withdrawal requests count %d exceeds the maximum %d", len(er.Withdrawals), params.BeaconConfig().MaxWithdrawalRequestsPerPayload)
+	}
+	withdrawals := make([]*v1.WithdrawalRequest, len(er.Withdrawals))
+	for i, wr := range er.Withdrawals {
+		w, err := wr.ToProto()
+		if err != nil {
+			return nil, err
+		}
+		withdrawals[i] = w
+	}
+	if uint64(len(er.Consolidations)) > params.BeaconConfig().MaxConsolidationsRequestsPerPayload {
+		return nil, fmt.Errorf("consolidation requests count %d exceeds the maximum %d", len(er.Consolidations), params.BeaconConfig().MaxConsolidationsRequestsPerPayload)
+	}
+	consolidations := make([]*v1.ConsolidationRequest, len(er.Consolidations))
+	for i, con := range er.Consolidations {
+		c, err := con.ToProto()
+		if err != nil {
+			return nil, err
+		}
+		consolidations[i] = c
+	}
+	return &v1.ExecutionRequests{
+		Deposits:       deposits,
+		Withdrawals:    withdrawals,
+		Consolidations: consolidations,
+	}, nil
+}
+
+// BuilderBidElectra is a field of ExecHeaderResponseElectra.
+type BuilderBidElectra struct {
+	Header             *ExecutionPayloadHeaderDeneb `json:"header"`
+	BlobKzgCommitments []hexutil.Bytes              `json:"blob_kzg_commitments"`
+	ExecutionRequests  *ExecutionRequestsV1         `json:"execution_requests"`
+	Value              Uint256                      `json:"value"`
+	Pubkey             hexutil.Bytes                `json:"pubkey"`
+}
+
+// WithdrawalRequestV1 is a field of ExecutionRequestsV1.
+type WithdrawalRequestV1 struct {
+	SourceAddress   hexutil.Bytes `json:"source_address"`
+	ValidatorPubkey hexutil.Bytes `json:"validator_pubkey"`
+	Amount          Uint256       `json:"amount"`
+}
+
+func (wr *WithdrawalRequestV1) ToProto() (*v1.WithdrawalRequest, error) {
+	srcAddress, err := bytesutil.DecodeHexWithLength(wr.SourceAddress.String(), common.AddressLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "source_address")
+	}
+	pubkey, err := bytesutil.DecodeHexWithLength(wr.ValidatorPubkey.String(), fieldparams.BLSPubkeyLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "validator_pubkey")
+	}
+
+	return &v1.WithdrawalRequest{
+		SourceAddress:   srcAddress,
+		ValidatorPubkey: pubkey,
+		Amount:          wr.Amount.Uint64(),
+	}, nil
+}
+
+// DepositRequestV1 is a field of ExecutionRequestsV1.
+type DepositRequestV1 struct {
+	PubKey hexutil.Bytes `json:"pubkey"`
+	// withdrawalCredentials: DATA, 32 Bytes
+	WithdrawalCredentials hexutil.Bytes `json:"withdrawal_credentials"`
+	// amount: QUANTITY, 64 Bits
+	Amount Uint256 `json:"amount"`
+	// signature: DATA, 96 Bytes
+	Signature hexutil.Bytes `json:"signature"`
+	// index: QUANTITY, 64 Bits
+	Index Uint256 `json:"index"`
+}
+
+func (dr *DepositRequestV1) ToProto() (*v1.DepositRequest, error) {
+	pubkey, err := bytesutil.DecodeHexWithLength(dr.PubKey.String(), fieldparams.BLSPubkeyLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "pubkey")
+	}
+	wc, err := bytesutil.DecodeHexWithLength(dr.WithdrawalCredentials.String(), fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "withdrawal_credentials")
+	}
+	sig, err := bytesutil.DecodeHexWithLength(dr.Signature.String(), fieldparams.BLSSignatureLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "signature")
+	}
+	return &v1.DepositRequest{
+		Pubkey:                pubkey,
+		WithdrawalCredentials: wc,
+		Amount:                dr.Amount.Uint64(),
+		Signature:             sig,
+		Index:                 dr.Index.Uint64(),
+	}, nil
+}
+
+// ConsolidationRequestV1 is a field of ExecutionRequestsV1.
+type ConsolidationRequestV1 struct {
+	// sourceAddress: DATA, 20 Bytes
+	SourceAddress hexutil.Bytes `json:"source_address"`
+	// sourcePubkey: DATA, 48 Bytes
+	SourcePubkey hexutil.Bytes `json:"source_pubkey"`
+	// targetPubkey: DATA, 48 Bytes
+	TargetPubkey hexutil.Bytes `json:"target_pubkey"`
+}
+
+func (cr *ConsolidationRequestV1) ToProto() (*v1.ConsolidationRequest, error) {
+	srcAddress, err := bytesutil.DecodeHexWithLength(cr.SourceAddress.String(), common.AddressLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "source_address")
+	}
+	sourcePubkey, err := bytesutil.DecodeHexWithLength(cr.SourcePubkey.String(), fieldparams.BLSPubkeyLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "source_pubkey")
+	}
+	targetPubkey, err := bytesutil.DecodeHexWithLength(cr.TargetPubkey.String(), fieldparams.BLSPubkeyLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "target_pubkey")
+	}
+	return &v1.ConsolidationRequest{
+		SourceAddress: srcAddress,
+		SourcePubkey:  sourcePubkey,
+		TargetPubkey:  targetPubkey,
+	}, nil
+}
+
 // ErrorMessage is a JSON representation of the builder API's returned error message.
 type ErrorMessage struct {
 	Code        int      `json:"code"`

api/client/builder/types_test.go

@@ -11,15 +11,18 @@ import (
 	"os"
 	"testing"
 
+	"github.com/OffchainLabs/prysm/v6/api/server/structs"
+	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
+	consensusblocks "github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v6/math"
+	v1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
+	eth "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/runtime/version"
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/go-bitfield"
-	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
-	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/v5/math"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
 )
 
 func ezDecode(t *testing.T, s string) []byte {
@@ -151,6 +154,64 @@ var testExampleHeaderResponseDeneb = `{
   }
 }`
 
+var testExampleHeaderResponseElectra = `{
+  "version": "electra",
+  "data": {
+    "message": {
+      "header": {
+        "parent_hash": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "fee_recipient": "0xabcf8e0d4e9587369b2301d0790347320302cc09",
+        "state_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "receipts_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "logs_bloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+        "prev_randao": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "block_number": "1",
+        "gas_limit": "1",
+        "gas_used": "1",
+        "timestamp": "1",
+        "extra_data": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "base_fee_per_gas": "1",
+        "blob_gas_used": "1",
+        "excess_blob_gas": "1",
+        "block_hash": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "transactions_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "withdrawals_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"
+      },
+      "blob_kzg_commitments": [
+        "0xa94170080872584e54a1cf092d845703b13907f2e6b3b1c0ad573b910530499e3bcd48c6378846b80d2bfa58c81cf3d5"
+      ],
+      "execution_requests": {
+        "deposits": [
+          {
+            "pubkey": "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a",
+            "withdrawal_credentials": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+            "amount": "1",
+            "signature": "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505",
+            "index": "1"
+          }
+        ],
+        "withdrawals": [
+          {
+            "source_address": "0xabcf8e0d4e9587369b2301d0790347320302cc09",
+            "validator_pubkey": "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a",
+            "amount": "1"
+          }
+        ],
+        "consolidations": [
+          {
+            "source_address": "0xabcf8e0d4e9587369b2301d0790347320302cc09",
+            "source_pubkey": "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a",
+            "target_pubkey": "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"
+          }
+        ]
+      },
+      "value": "652312848583266388373324160190187140051835877600158453279131187530910662656",
+      "pubkey": "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"
+    },
+    "signature": "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"
+  }
+}`
+
 var testExampleHeaderResponseDenebNoBundle = `{
   "version": "deneb",
   "data": {
@@ -1600,7 +1661,6 @@ func TestBuilderBidUnmarshalUint256(t *testing.T) {
 	require.NoError(t, expectedValue.UnmarshalText([]byte(base10)))
 	r := &ExecHeaderResponse{}
 	require.NoError(t, json.Unmarshal([]byte(testBuilderBid), r))
-	//require.Equal(t, expectedValue, r.Data.Message.Value)
 	marshaled := r.Data.Message.Value.String()
 	require.Equal(t, base10, marshaled)
 	require.Equal(t, 0, expectedValue.Cmp(r.Data.Message.Value.Int))
@@ -1907,3 +1967,41 @@ func TestErrorMessage_non200Err(t *testing.T) {
 		})
 	}
 }
+
+func TestEmptyResponseBody(t *testing.T) {
+	t.Run("empty buffer", func(t *testing.T) {
+		var b []byte
+		r := &ExecutionPayloadResponse{}
+		err := json.Unmarshal(b, r)
+		var syntaxError *json.SyntaxError
+		ok := errors.As(err, &syntaxError)
+		require.Equal(t, true, ok)
+	})
+	t.Run("empty object", func(t *testing.T) {
+		empty := []byte("{}")
+		emptyResponse := &ExecutionPayloadResponse{}
+		require.NoError(t, json.Unmarshal(empty, emptyResponse))
+		_, err := emptyResponse.ParsePayload()
+		require.ErrorContains(t, "unsupported version", err)
+	})
+	versions := []int{version.Bellatrix, version.Capella, version.Deneb, version.Electra}
+	for i := range versions {
+		vstr := version.String(versions[i])
+		t.Run("populated version without payload"+vstr, func(t *testing.T) {
+			in := &ExecutionPayloadResponse{Version: vstr}
+			encoded, err := json.Marshal(in)
+			require.NoError(t, err)
+			epr := &ExecutionPayloadResponse{}
+			require.NoError(t, json.Unmarshal(encoded, epr))
+			pp, err := epr.ParsePayload()
+			require.NoError(t, err)
+			pb, err := pp.PayloadProto()
+			if err == nil {
+				require.NoError(t, err)
+				require.Equal(t, false, pb == nil)
+			} else {
+				require.ErrorIs(t, err, consensusblocks.ErrNilObject)
+			}
+		})
+	}
+}

api/client/client.go

@@ -10,11 +10,18 @@ import (
 	"github.com/pkg/errors"
 )
 
+const (
+	MaxBodySize      int64 = 1 << 23 // 8MB default, WithMaxBodySize can override
+	MaxBodySizeState int64 = 1 << 29 // 512MB
+	MaxErrBodySize   int64 = 1 << 17 // 128KB
+)
+
 // Client is a wrapper object around the HTTP client.
 type Client struct {
-	hc      *http.Client
-	baseURL *url.URL
-	token   string
+	hc          *http.Client
+	baseURL     *url.URL
+	token       string
+	maxBodySize int64
 }
 
 // NewClient constructs a new client with the provided options (ex WithTimeout).
@@ -26,8 +33,9 @@ func NewClient(host string, opts ...ClientOpt) (*Client, error) {
 		return nil, err
 	}
 	c := &Client{
-		hc:      &http.Client{},
-		baseURL: u,
+		hc:          &http.Client{},
+		baseURL:     u,
+		maxBodySize: MaxBodySize,
 	}
 	for _, o := range opts {
 		o(c)
@@ -72,7 +80,7 @@ func (c *Client) NodeURL() string {
 // Get is a generic, opinionated GET function to reduce boilerplate amongst the getters in this package.
 func (c *Client) Get(ctx context.Context, path string, opts ...ReqOption) ([]byte, error) {
 	u := c.baseURL.ResolveReference(&url.URL{Path: path})
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), http.NoBody)
 	if err != nil {
 		return nil, err
 	}
@@ -89,7 +97,7 @@ func (c *Client) Get(ctx context.Context, path string, opts ...ReqOption) ([]byt
 	if r.StatusCode != http.StatusOK {
 		return nil, Non200Err(r)
 	}
-	b, err := io.ReadAll(r.Body)
+	b, err := io.ReadAll(io.LimitReader(r.Body, c.maxBodySize))
 	if err != nil {
 		return nil, errors.Wrap(err, "error reading http response body")
 	}

api/client/client_test.go

@@ -4,7 +4,7 @@ import (
 	"net/url"
 	"testing"
 
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
 )
 
 func TestValidHostname(t *testing.T) {

api/client/errors.go

@@ -25,16 +25,16 @@ var ErrInvalidNodeVersion = errors.New("invalid node version response")
 var ErrConnectionIssue = errors.New("could not connect")
 
 // Non200Err is a function that parses an HTTP response to handle responses that are not 200 with a formatted error.
-func Non200Err(response *http.Response) error {
-	bodyBytes, err := io.ReadAll(response.Body)
+func Non200Err(r *http.Response) error {
+	b, err := io.ReadAll(io.LimitReader(r.Body, MaxErrBodySize))
 	var body string
 	if err != nil {
 		body = "(Unable to read response body.)"
 	} else {
-		body = "response body:\n" + string(bodyBytes)
+		body = "response body:\n" + string(b)
 	}
-	msg := fmt.Sprintf("code=%d, url=%s, body=%s", response.StatusCode, response.Request.URL, body)
-	switch response.StatusCode {
+	msg := fmt.Sprintf("code=%d, url=%s, body=%s", r.StatusCode, r.Request.URL, body)
+	switch r.StatusCode {
 	case http.StatusNotFound:
 		return errors.Wrap(ErrNotFound, msg)
 	default:

api/client/event/BUILD.bazel

@@ -2,8 +2,11 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "go_default_library",
-    srcs = ["event_stream.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/event",
+    srcs = [
+        "event_stream.go",
+        "utils.go",
+    ],
+    importpath = "github.com/OffchainLabs/prysm/v6/api/client/event",
     visibility = ["//visibility:public"],
     deps = [
         "//api:go_default_library",
@@ -15,7 +18,10 @@ go_library(
 
 go_test(
     name = "go_default_test",
-    srcs = ["event_stream_test.go"],
+    srcs = [
+        "event_stream_test.go",
+        "utils_test.go",
+    ],
     embed = [":go_default_library"],
     deps = [
         "//testing/require:go_default_library",

api/client/event/event_stream.go

@@ -7,9 +7,9 @@ import (
 	"net/url"
 	"strings"
 
+	"github.com/OffchainLabs/prysm/v6/api"
+	"github.com/OffchainLabs/prysm/v6/api/client"
 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api"
-	"github.com/prysmaticlabs/prysm/v5/api/client"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -93,6 +93,7 @@ func (h *EventStream) Subscribe(eventsChannel chan<- *Event) {
 			EventType: EventConnectionError,
 			Data:      []byte(errors.Wrap(err, client.ErrConnectionIssue.Error()).Error()),
 		}
+		return
 	}
 
 	defer func() {
@@ -102,6 +103,8 @@ func (h *EventStream) Subscribe(eventsChannel chan<- *Event) {
 	}()
 	// Create a new scanner to read lines from the response body
 	scanner := bufio.NewScanner(resp.Body)
+	// Set the split function for the scanning operation
+	scanner.Split(scanLinesWithCarriage)
 
 	var eventType, data string // Variables to store event type and data
 
@@ -113,7 +116,7 @@ func (h *EventStream) Subscribe(eventsChannel chan<- *Event) {
 			close(eventsChannel)
 			return
 		default:
-			line := scanner.Text() // TODO(13730): scanner does not handle /r and does not fully adhere to https://html.spec.whatwg.org/multipage/server-sent-events.html#the-eventsource-interface
+			line := scanner.Text()
 			// Handle the event based on your specific format
 			if line == "" {
 				// Empty line indicates the end of an event

api/client/event/event_stream_test.go

@@ -8,7 +8,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -40,11 +40,12 @@ func TestNewEventStream(t *testing.T) {
 
 func TestEventStream(t *testing.T) {
 	mux := http.NewServeMux()
-	mux.HandleFunc("/eth/v1/events", func(w http.ResponseWriter, r *http.Request) {
+	mux.HandleFunc("/eth/v1/events", func(w http.ResponseWriter, _ *http.Request) {
 		flusher, ok := w.(http.Flusher)
 		require.Equal(t, true, ok)
-		for i := 1; i <= 2; i++ {
-			_, err := fmt.Fprintf(w, "event: head\ndata: data%d\n\n", i)
+		for i := 1; i <= 3; i++ {
+			events := [3]string{"event: head\ndata: data%d\n\n", "event: head\rdata: data%d\r\r", "event: head\r\ndata: data%d\r\n\r\n"}
+			_, err := fmt.Fprintf(w, events[i-1], i)
 			require.NoError(t, err)
 			flusher.Flush()                    // Trigger flush to simulate streaming data
 			time.Sleep(100 * time.Millisecond) // Simulate delay between events
@@ -62,7 +63,7 @@ func TestEventStream(t *testing.T) {
 	// Collect events
 	var events []*Event
 
-	for len(events) != 2 {
+	for len(events) != 3 {
 		select {
 		case event := <-eventsChannel:
 			log.Info(event)
@@ -71,10 +72,30 @@ func TestEventStream(t *testing.T) {
 	}
 
 	// Assertions to verify the events content
-	expectedData := []string{"data1", "data2"}
+	expectedData := []string{"data1", "data2", "data3"}
 	for i, event := range events {
 		if string(event.Data) != expectedData[i] {
 			t.Errorf("Expected event data %q, got %q", expectedData[i], string(event.Data))
 		}
 	}
 }
+
+func TestEventStreamRequestError(t *testing.T) {
+	topics := []string{"head"}
+	eventsChannel := make(chan *Event, 1)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	// use valid url that will result in failed request with nil body
+	stream, err := NewEventStream(ctx, http.DefaultClient, "http://badhost:1234", topics)
+	require.NoError(t, err)
+
+	// error will happen when request is made, should be received over events channel
+	go stream.Subscribe(eventsChannel)
+
+	event := <-eventsChannel
+	if event.EventType != EventConnectionError {
+		t.Errorf("Expected event type %q, got %q", EventConnectionError, event.EventType)
+	}
+
+}

api/client/event/utils.go

@@ -0,0 +1,36 @@
+package event
+
+import (
+	"bytes"
+)
+
+// adapted from ScanLines in scan.go to handle carriage return characters as separators
+func scanLinesWithCarriage(data []byte, atEOF bool) (advance int, token []byte, err error) {
+	if atEOF && len(data) == 0 {
+		return 0, nil, nil
+	}
+	if i, j := bytes.IndexByte(data, '\n'), bytes.IndexByte(data, '\r'); i >= 0 || j >= 0 {
+		in := i
+		// Select the first index of \n or \r or the second index of \r if it is followed by \n
+		if i < 0 || (i > j && i != j+1 && j >= 0) {
+			in = j
+		}
+
+		// We have a full newline-terminated line.
+		return in + 1, dropCR(data[0:in]), nil
+	}
+	// If we're at EOF, we have a final, non-terminated line. Return it.
+	if atEOF {
+		return len(data), dropCR(data), nil
+	}
+	// Request more data.
+	return 0, nil, nil
+}
+
+// dropCR drops a terminal \r from the data.
+func dropCR(data []byte) []byte {
+	if len(data) > 0 && data[len(data)-1] == '\r' {
+		return data[0 : len(data)-1]
+	}
+	return data
+}

api/client/event/utils_test.go

@@ -0,0 +1,97 @@
+package event
+
+import (
+	"bufio"
+	"bytes"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+)
+
+func TestScanLinesWithCarriage(t *testing.T) {
+	testCases := []struct {
+		name     string
+		input    string
+		expected []string
+	}{
+		{
+			name:     "LF line endings",
+			input:    "line1\nline2\nline3",
+			expected: []string{"line1", "line2", "line3"},
+		},
+		{
+			name:     "CR line endings",
+			input:    "line1\rline2\rline3",
+			expected: []string{"line1", "line2", "line3"},
+		},
+		{
+			name:     "CRLF line endings",
+			input:    "line1\r\nline2\r\nline3",
+			expected: []string{"line1", "line2", "line3"},
+		},
+		{
+			name:     "Mixed line endings",
+			input:    "line1\nline2\rline3\r\nline4",
+			expected: []string{"line1", "line2", "line3", "line4"},
+		},
+		{
+			name:     "Empty lines",
+			input:    "line1\n\nline2\r\rline3",
+			expected: []string{"line1", "", "line2", "", "line3"},
+		},
+		{
+			name:     "Empty lines 2",
+			input:    "line1\n\rline2\n\rline3",
+			expected: []string{"line1", "", "line2", "", "line3"},
+		},
+		{
+			name:     "No line endings",
+			input:    "single line without ending",
+			expected: []string{"single line without ending"},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			scanner := bufio.NewScanner(bytes.NewReader([]byte(tc.input)))
+			scanner.Split(scanLinesWithCarriage)
+
+			var lines []string
+			for scanner.Scan() {
+				lines = append(lines, scanner.Text())
+			}
+
+			require.NoError(t, scanner.Err())
+			require.Equal(t, len(tc.expected), len(lines), "Number of lines does not match")
+			for i, line := range lines {
+				require.Equal(t, tc.expected[i], line, "Line %d does not match", i)
+			}
+		})
+	}
+}
+
+// TestScanLinesWithCarriageEdgeCases tests edge cases and potential error scenarios
+func TestScanLinesWithCarriageEdgeCases(t *testing.T) {
+	t.Run("Empty input", func(t *testing.T) {
+		scanner := bufio.NewScanner(bytes.NewReader([]byte("")))
+		scanner.Split(scanLinesWithCarriage)
+		require.Equal(t, scanner.Scan(), false)
+		require.NoError(t, scanner.Err())
+	})
+
+	t.Run("Very long line", func(t *testing.T) {
+		longLine := bytes.Repeat([]byte("a"), bufio.MaxScanTokenSize+1)
+		scanner := bufio.NewScanner(bytes.NewReader(longLine))
+		scanner.Split(scanLinesWithCarriage)
+		require.Equal(t, scanner.Scan(), false)
+		require.NotNil(t, scanner.Err())
+	})
+
+	t.Run("Line ending at max token size", func(t *testing.T) {
+		input := append(bytes.Repeat([]byte("a"), bufio.MaxScanTokenSize-1), '\n')
+		scanner := bufio.NewScanner(bytes.NewReader(input))
+		scanner.Split(scanLinesWithCarriage)
+		require.Equal(t, scanner.Scan(), true)
+		require.Equal(t, string(bytes.Repeat([]byte("a"), bufio.MaxScanTokenSize-1)), scanner.Text())
+	})
+}

api/client/options.go

@@ -46,3 +46,10 @@ func WithAuthenticationToken(token string) ClientOpt {
 		c.token = token
 	}
 }
+
+// WithMaxBodySize overrides the default max body size of 8MB.
+func WithMaxBodySize(size int64) ClientOpt {
+	return func(c *Client) {
+		c.maxBodySize = size
+	}
+}

api/client/validator/BUILD.bazel

@@ -3,7 +3,7 @@ load("@prysm//tools/go:def.bzl", "go_library")
 go_library(
     name = "go_default_library",
     srcs = ["client.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/validator",
+    importpath = "github.com/OffchainLabs/prysm/v6/api/client/validator",
     visibility = ["//visibility:public"],
     deps = [
         "//api/client:go_default_library",

api/client/validator/client.go

@@ -6,9 +6,9 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/OffchainLabs/prysm/v6/api/client"
+	"github.com/OffchainLabs/prysm/v6/validator/rpc"
 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api/client"
-	"github.com/prysmaticlabs/prysm/v5/validator/rpc"
 )
 
 const (

api/constants.go

@@ -4,4 +4,6 @@ const (
 	WebUrlPrefix        = "/v2/validator/"
 	WebApiUrlPrefix     = "/api/v2/validator/"
 	KeymanagerApiPrefix = "/eth/v1"
+	SystemLogsPrefix    = "health/logs"
+	AuthTokenFileName   = "auth-token"
 )

api/gateway/BUILD.bazel

@@ -1,43 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "gateway.go",
-        "log.go",
-        "modifiers.go",
-        "options.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/gateway",
-    visibility = [
-        "//beacon-chain:__subpackages__",
-        "//validator:__subpackages__",
-    ],
-    deps = [
-        "//api/server:go_default_library",
-        "//runtime:go_default_library",
-        "@com_github_gorilla_mux//:go_default_library",
-        "@com_github_grpc_ecosystem_grpc_gateway_v2//runtime:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-        "@org_golang_google_grpc//:go_default_library",
-        "@org_golang_google_grpc//connectivity:go_default_library",
-        "@org_golang_google_grpc//credentials:go_default_library",
-        "@org_golang_google_grpc//credentials/insecure:go_default_library",
-        "@org_golang_google_protobuf//proto:go_default_library",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = ["gateway_test.go"],
-    embed = [":go_default_library"],
-    deps = [
-        "//cmd/beacon-chain/flags:go_default_library",
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-        "@com_github_gorilla_mux//:go_default_library",
-        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
-        "@com_github_urfave_cli_v2//:go_default_library",
-    ],
-)

api/gateway/gateway.go

@@ -1,212 +0,0 @@
-// Package gateway defines a grpc-gateway server that serves HTTP-JSON traffic and acts a proxy between HTTP and gRPC.
-package gateway
-
-import (
-	"context"
-	"fmt"
-	"net"
-	"net/http"
-	"time"
-
-	"github.com/gorilla/mux"
-	gwruntime "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
-	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api/server"
-	"github.com/prysmaticlabs/prysm/v5/runtime"
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/connectivity"
-	"google.golang.org/grpc/credentials"
-	"google.golang.org/grpc/credentials/insecure"
-)
-
-var _ runtime.Service = (*Gateway)(nil)
-
-// PbMux serves grpc-gateway requests for selected patterns using registered protobuf handlers.
-type PbMux struct {
-	Registrations []PbHandlerRegistration // Protobuf registrations to be registered in Mux.
-	Patterns      []string                // URL patterns that will be handled by Mux.
-	Mux           *gwruntime.ServeMux     // The router that will be used for grpc-gateway requests.
-}
-
-// PbHandlerRegistration is a function that registers a protobuf handler.
-type PbHandlerRegistration func(context.Context, *gwruntime.ServeMux, *grpc.ClientConn) error
-
-// MuxHandler is a function that implements the mux handler functionality.
-type MuxHandler func(
-	h http.HandlerFunc,
-	w http.ResponseWriter,
-	req *http.Request,
-)
-
-// Config parameters for setting up the gateway service.
-type config struct {
-	maxCallRecvMsgSize uint64
-	remoteCert         string
-	gatewayAddr        string
-	remoteAddr         string
-	allowedOrigins     []string
-	muxHandler         MuxHandler
-	pbHandlers         []*PbMux
-	router             *mux.Router
-	timeout            time.Duration
-}
-
-// Gateway is the gRPC gateway to serve HTTP JSON traffic as a proxy and forward it to the gRPC server.
-type Gateway struct {
-	cfg          *config
-	conn         *grpc.ClientConn
-	server       *http.Server
-	cancel       context.CancelFunc
-	ctx          context.Context
-	startFailure error
-}
-
-// New returns a new instance of the Gateway.
-func New(ctx context.Context, opts ...Option) (*Gateway, error) {
-	g := &Gateway{
-		ctx: ctx,
-		cfg: &config{},
-	}
-	for _, opt := range opts {
-		if err := opt(g); err != nil {
-			return nil, err
-		}
-	}
-	if g.cfg.router == nil {
-		g.cfg.router = mux.NewRouter()
-	}
-	return g, nil
-}
-
-// Start the gateway service.
-func (g *Gateway) Start() {
-	ctx, cancel := context.WithCancel(g.ctx)
-	g.cancel = cancel
-
-	conn, err := g.dial(ctx, "tcp", g.cfg.remoteAddr)
-	if err != nil {
-		log.WithError(err).Error("Failed to connect to gRPC server")
-		g.startFailure = err
-		return
-	}
-	g.conn = conn
-
-	for _, h := range g.cfg.pbHandlers {
-		for _, r := range h.Registrations {
-			if err := r(ctx, h.Mux, g.conn); err != nil {
-				log.WithError(err).Error("Failed to register handler")
-				g.startFailure = err
-				return
-			}
-		}
-		for _, p := range h.Patterns {
-			g.cfg.router.PathPrefix(p).Handler(h.Mux)
-		}
-	}
-
-	corsMux := server.CorsHandler(g.cfg.allowedOrigins).Middleware(g.cfg.router)
-
-	if g.cfg.muxHandler != nil {
-		g.cfg.router.PathPrefix("/").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			g.cfg.muxHandler(corsMux.ServeHTTP, w, r)
-		})
-	}
-
-	g.server = &http.Server{
-		Addr:              g.cfg.gatewayAddr,
-		Handler:           corsMux,
-		ReadHeaderTimeout: time.Second,
-	}
-
-	go func() {
-		log.WithField("address", g.cfg.gatewayAddr).Info("Starting gRPC gateway")
-		if err := g.server.ListenAndServe(); err != http.ErrServerClosed {
-			log.WithError(err).Error("Failed to start gRPC gateway")
-			g.startFailure = err
-			return
-		}
-	}()
-}
-
-// Status of grpc gateway. Returns an error if this service is unhealthy.
-func (g *Gateway) Status() error {
-	if g.startFailure != nil {
-		return g.startFailure
-	}
-	if s := g.conn.GetState(); s != connectivity.Ready {
-		return fmt.Errorf("grpc server is %s", s)
-	}
-	return nil
-}
-
-// Stop the gateway with a graceful shutdown.
-func (g *Gateway) Stop() error {
-	if g.server != nil {
-		shutdownCtx, shutdownCancel := context.WithTimeout(g.ctx, 2*time.Second)
-		defer shutdownCancel()
-		if err := g.server.Shutdown(shutdownCtx); err != nil {
-			if errors.Is(err, context.DeadlineExceeded) {
-				log.Warn("Existing connections terminated")
-			} else {
-				log.WithError(err).Error("Failed to gracefully shut down server")
-			}
-		}
-	}
-	if g.cancel != nil {
-		g.cancel()
-	}
-	return nil
-}
-
-// dial the gRPC server.
-func (g *Gateway) dial(ctx context.Context, network, addr string) (*grpc.ClientConn, error) {
-	switch network {
-	case "tcp":
-		return g.dialTCP(ctx, addr)
-	case "unix":
-		return g.dialUnix(ctx, addr)
-	default:
-		return nil, fmt.Errorf("unsupported network type %q", network)
-	}
-}
-
-// dialTCP creates a client connection via TCP.
-// "addr" must be a valid TCP address with a port number.
-func (g *Gateway) dialTCP(ctx context.Context, addr string) (*grpc.ClientConn, error) {
-	var security grpc.DialOption
-	if len(g.cfg.remoteCert) > 0 {
-		creds, err := credentials.NewClientTLSFromFile(g.cfg.remoteCert, "")
-		if err != nil {
-			return nil, err
-		}
-		security = grpc.WithTransportCredentials(creds)
-	} else {
-		// Use insecure credentials when there's no remote cert provided.
-		security = grpc.WithTransportCredentials(insecure.NewCredentials())
-	}
-	opts := []grpc.DialOption{
-		security,
-		grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(int(g.cfg.maxCallRecvMsgSize))),
-	}
-	return grpc.DialContext(ctx, addr, opts...)
-}
-
-// dialUnix creates a client connection via a unix domain socket.
-// "addr" must be a valid path to the socket.
-func (g *Gateway) dialUnix(ctx context.Context, addr string) (*grpc.ClientConn, error) {
-	d := func(addr string, timeout time.Duration) (net.Conn, error) {
-		return net.DialTimeout("unix", addr, timeout)
-	}
-	f := func(ctx context.Context, addr string) (net.Conn, error) {
-		if deadline, ok := ctx.Deadline(); ok {
-			return d(addr, time.Until(deadline))
-		}
-		return d(addr, 0)
-	}
-	opts := []grpc.DialOption{
-		grpc.WithTransportCredentials(insecure.NewCredentials()),
-		grpc.WithContextDialer(f),
-		grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(int(g.cfg.maxCallRecvMsgSize))),
-	}
-	return grpc.DialContext(ctx, addr, opts...)
-}

api/gateway/gateway_test.go

@@ -1,107 +0,0 @@
-package gateway
-
-import (
-	"context"
-	"flag"
-	"fmt"
-	"net/http"
-	"net/http/httptest"
-	"net/url"
-	"testing"
-
-	"github.com/gorilla/mux"
-	"github.com/prysmaticlabs/prysm/v5/cmd/beacon-chain/flags"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-	logTest "github.com/sirupsen/logrus/hooks/test"
-	"github.com/urfave/cli/v2"
-)
-
-func TestGateway_Customized(t *testing.T) {
-	r := mux.NewRouter()
-	cert := "cert"
-	origins := []string{"origin"}
-	size := uint64(100)
-
-	opts := []Option{
-		WithRouter(r),
-		WithRemoteCert(cert),
-		WithAllowedOrigins(origins),
-		WithMaxCallRecvMsgSize(size),
-		WithMuxHandler(func(
-			_ http.HandlerFunc,
-			_ http.ResponseWriter,
-			_ *http.Request,
-		) {
-		}),
-	}
-
-	g, err := New(context.Background(), opts...)
-	require.NoError(t, err)
-
-	assert.Equal(t, r, g.cfg.router)
-	assert.Equal(t, cert, g.cfg.remoteCert)
-	require.Equal(t, 1, len(g.cfg.allowedOrigins))
-	assert.Equal(t, origins[0], g.cfg.allowedOrigins[0])
-	assert.Equal(t, size, g.cfg.maxCallRecvMsgSize)
-}
-
-func TestGateway_StartStop(t *testing.T) {
-	hook := logTest.NewGlobal()
-
-	app := cli.App{}
-	set := flag.NewFlagSet("test", 0)
-	ctx := cli.NewContext(&app, set, nil)
-
-	gatewayPort := ctx.Int(flags.GRPCGatewayPort.Name)
-	gatewayHost := ctx.String(flags.GRPCGatewayHost.Name)
-	rpcHost := ctx.String(flags.RPCHost.Name)
-	selfAddress := fmt.Sprintf("%s:%d", rpcHost, ctx.Int(flags.RPCPort.Name))
-	gatewayAddress := fmt.Sprintf("%s:%d", gatewayHost, gatewayPort)
-
-	opts := []Option{
-		WithGatewayAddr(gatewayAddress),
-		WithRemoteAddr(selfAddress),
-		WithMuxHandler(func(
-			_ http.HandlerFunc,
-			_ http.ResponseWriter,
-			_ *http.Request,
-		) {
-		}),
-	}
-
-	g, err := New(context.Background(), opts...)
-	require.NoError(t, err)
-
-	g.Start()
-	go func() {
-		require.LogsContain(t, hook, "Starting gRPC gateway")
-		require.LogsDoNotContain(t, hook, "Starting API middleware")
-	}()
-	err = g.Stop()
-	require.NoError(t, err)
-}
-
-func TestGateway_NilHandler_NotFoundHandlerRegistered(t *testing.T) {
-	app := cli.App{}
-	set := flag.NewFlagSet("test", 0)
-	ctx := cli.NewContext(&app, set, nil)
-
-	gatewayPort := ctx.Int(flags.GRPCGatewayPort.Name)
-	gatewayHost := ctx.String(flags.GRPCGatewayHost.Name)
-	rpcHost := ctx.String(flags.RPCHost.Name)
-	selfAddress := fmt.Sprintf("%s:%d", rpcHost, ctx.Int(flags.RPCPort.Name))
-	gatewayAddress := fmt.Sprintf("%s:%d", gatewayHost, gatewayPort)
-
-	opts := []Option{
-		WithGatewayAddr(gatewayAddress),
-		WithRemoteAddr(selfAddress),
-	}
-
-	g, err := New(context.Background(), opts...)
-	require.NoError(t, err)
-
-	writer := httptest.NewRecorder()
-	g.cfg.router.ServeHTTP(writer, &http.Request{Method: "GET", Host: "localhost", URL: &url.URL{Path: "/foo"}})
-	assert.Equal(t, http.StatusNotFound, writer.Code)
-}

api/gateway/log.go

@@ -1,5 +0,0 @@
-package gateway
-
-import "github.com/sirupsen/logrus"
-
-var log = logrus.WithField("prefix", "gateway")

api/gateway/modifiers.go

@@ -1,30 +0,0 @@
-package gateway
-
-import (
-	"context"
-	"net/http"
-	"strconv"
-
-	gwruntime "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
-	"google.golang.org/protobuf/proto"
-)
-
-func HttpResponseModifier(ctx context.Context, w http.ResponseWriter, _ proto.Message) error {
-	md, ok := gwruntime.ServerMetadataFromContext(ctx)
-	if !ok {
-		return nil
-	}
-	// set http status code
-	if vals := md.HeaderMD.Get("x-http-code"); len(vals) > 0 {
-		code, err := strconv.Atoi(vals[0])
-		if err != nil {
-			return err
-		}
-		// delete the headers to not expose any grpc-metadata in http response
-		delete(md.HeaderMD, "x-http-code")
-		delete(w.Header(), "Grpc-Metadata-X-Http-Code")
-		w.WriteHeader(code)
-	}
-
-	return nil
-}

api/gateway/options.go

@@ -1,79 +0,0 @@
-package gateway
-
-import (
-	"time"
-
-	"github.com/gorilla/mux"
-	gwruntime "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
-)
-
-type Option func(g *Gateway) error
-
-func WithPbHandlers(handlers []*PbMux) Option {
-	return func(g *Gateway) error {
-		g.cfg.pbHandlers = handlers
-		return nil
-	}
-}
-
-func WithMuxHandler(m MuxHandler) Option {
-	return func(g *Gateway) error {
-		g.cfg.muxHandler = m
-		return nil
-	}
-}
-
-func WithGatewayAddr(addr string) Option {
-	return func(g *Gateway) error {
-		g.cfg.gatewayAddr = addr
-		return nil
-	}
-}
-
-func WithRemoteAddr(addr string) Option {
-	return func(g *Gateway) error {
-		g.cfg.remoteAddr = addr
-		return nil
-	}
-}
-
-// WithRouter allows adding a custom mux router to the gateway.
-func WithRouter(r *mux.Router) Option {
-	return func(g *Gateway) error {
-		g.cfg.router = r
-		return nil
-	}
-}
-
-// WithAllowedOrigins allows adding a set of allowed origins to the gateway.
-func WithAllowedOrigins(origins []string) Option {
-	return func(g *Gateway) error {
-		g.cfg.allowedOrigins = origins
-		return nil
-	}
-}
-
-// WithRemoteCert allows adding a custom certificate to the gateway,
-func WithRemoteCert(cert string) Option {
-	return func(g *Gateway) error {
-		g.cfg.remoteCert = cert
-		return nil
-	}
-}
-
-// WithMaxCallRecvMsgSize allows specifying the maximum allowed gRPC message size.
-func WithMaxCallRecvMsgSize(size uint64) Option {
-	return func(g *Gateway) error {
-		g.cfg.maxCallRecvMsgSize = size
-		return nil
-	}
-}
-
-// WithTimeout allows changing the timeout value for API calls.
-func WithTimeout(seconds uint64) Option {
-	return func(g *Gateway) error {
-		g.cfg.timeout = time.Second * time.Duration(seconds)
-		gwruntime.DefaultContextTimeout = time.Second * time.Duration(seconds)
-		return nil
-	}
-}

api/grpc/BUILD.bazel

@@ -6,7 +6,7 @@ go_library(
         "grpcutils.go",
         "parameters.go",
     ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/grpc",
+    importpath = "github.com/OffchainLabs/prysm/v6/api/grpc",
     visibility = ["//visibility:public"],
     deps = [
         "@com_github_sirupsen_logrus//:go_default_library",
@@ -22,9 +22,7 @@ go_test(
     deps = [
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
-        "@com_github_grpc_ecosystem_grpc_gateway_v2//runtime:go_default_library",
         "@com_github_sirupsen_logrus//hooks/test:go_default_library",
-        "@org_golang_google_grpc//:go_default_library",
         "@org_golang_google_grpc//metadata:go_default_library",
     ],
 )

api/grpc/grpcutils.go

@@ -2,8 +2,6 @@ package grpc
 
 import (
 	"context"
-	"encoding/json"
-	"fmt"
 	"strings"
 	"time"
 
@@ -76,21 +74,8 @@ func AppendHeaders(parent context.Context, headers []string) context.Context {
 				logrus.Warnf("Incorrect gRPC header flag format. Skipping %v", keyValue[0])
 				continue
 			}
-			parent = metadata.AppendToOutgoingContext(parent, keyValue[0], strings.Join(keyValue[1:], "="))
+			parent = metadata.AppendToOutgoingContext(parent, keyValue[0], strings.Join(keyValue[1:], "=")) // nolint:fatcontext
 		}
 	}
 	return parent
 }
-
-// AppendCustomErrorHeader sets a CustomErrorMetadataKey gRPC header on the passed in context,
-// using the passed in error data as the header's value. The data is serialized as JSON.
-func AppendCustomErrorHeader(ctx context.Context, errorData interface{}) error {
-	j, err := json.Marshal(errorData)
-	if err != nil {
-		return fmt.Errorf("could not marshal error data into JSON: %w", err)
-	}
-	if err := grpc.SetHeader(ctx, metadata.Pairs(CustomErrorMetadataKey, string(j))); err != nil {
-		return fmt.Errorf("could not set custom error header: %w", err)
-	}
-	return nil
-}

api/grpc/grpcutils_test.go

@@ -2,15 +2,11 @@ package grpc
 
 import (
 	"context"
-	"encoding/json"
-	"strings"
 	"testing"
 
-	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
 	logTest "github.com/sirupsen/logrus/hooks/test"
-	"google.golang.org/grpc"
 	"google.golang.org/grpc/metadata"
 )
 
@@ -62,17 +58,3 @@ func TestAppendHeaders(t *testing.T) {
 		assert.Equal(t, "value=1", md.Get("first")[0])
 	})
 }
-
-func TestAppendCustomErrorHeader(t *testing.T) {
-	stream := &runtime.ServerTransportStream{}
-	ctx := grpc.NewContextWithServerTransportStream(context.Background(), stream)
-	data := &customErrorData{Message: "foo"}
-	require.NoError(t, AppendCustomErrorHeader(ctx, data))
-	// The stream used in test setup sets the metadata key in lowercase.
-	value, ok := stream.Header()[strings.ToLower(CustomErrorMetadataKey)]
-	require.Equal(t, true, ok, "Failed to retrieve custom error metadata value")
-	expected, err := json.Marshal(data)
-	require.NoError(t, err)
-	assert.Equal(t, string(expected), value[0])
-
-}

api/headers.go

@@ -1,5 +1,7 @@
 package api
 
+import "net/http"
+
 const (
 	VersionHeader                 = "Eth-Consensus-Version"
 	ExecutionPayloadBlindedHeader = "Eth-Execution-Payload-Blinded"
@@ -10,3 +12,9 @@ const (
 	EventStreamMediaType          = "text/event-stream"
 	KeepAlive                     = "keep-alive"
 )
+
+// SetSSEHeaders sets the headers needed for a server-sent event response.
+func SetSSEHeaders(w http.ResponseWriter) {
+	w.Header().Set("Content-Type", EventStreamMediaType)
+	w.Header().Set("Connection", KeepAlive)
+}

api/jwt.go

@@ -0,0 +1,32 @@
+package api
+
+import (
+	"github.com/OffchainLabs/prysm/v6/crypto/rand"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/pkg/errors"
+)
+
+// GenerateRandomHexString generates a random hex string that follows the standards for jwt token
+// used for beacon node -> execution client
+// used for web client -> validator client
+func GenerateRandomHexString() (string, error) {
+	secret := make([]byte, 32)
+	randGen := rand.NewGenerator()
+	n, err := randGen.Read(secret)
+	if err != nil {
+		return "", err
+	} else if n != 32 {
+		return "", errors.New("rand: unexpected length")
+	}
+	return hexutil.Encode(secret), nil
+}
+
+// ValidateAuthToken validating auth token for web
+func ValidateAuthToken(token string) error {
+	b, err := hexutil.Decode(token)
+	// token should be hex-encoded and at least 256 bits
+	if err != nil || len(b) < 32 {
+		return errors.New("invalid auth token: token should be hex-encoded and at least 256 bits")
+	}
+	return nil
+}

api/jwt_test.go

@@ -0,0 +1,13 @@
+package api
+
+import (
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+)
+
+func TestGenerateRandomHexString(t *testing.T) {
+	token, err := GenerateRandomHexString()
+	require.NoError(t, err)
+	require.NoError(t, ValidateAuthToken(token))
+}

api/pagination/BUILD.bazel

@@ -3,7 +3,7 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = ["pagination.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/pagination",
+    importpath = "github.com/OffchainLabs/prysm/v6/api/pagination",
     visibility = ["//visibility:public"],
     deps = [
         "//config/params:go_default_library",

api/pagination/pagination.go

@@ -5,8 +5,8 @@ import (
 	"fmt"
 	"strconv"
 
+	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/config/params"
 )
 
 // StartAndEndPage takes in the requested page token, wanted page size, total page size.

api/pagination/pagination_test.go

@@ -3,9 +3,9 @@ package pagination_test
 import (
 	"testing"
 
-	"github.com/prysmaticlabs/prysm/v5/api/pagination"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/OffchainLabs/prysm/v6/api/pagination"
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
 )
 
 func TestStartAndEndPage(t *testing.T) {

api/server/BUILD.bazel

@@ -2,29 +2,14 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "go_default_library",
-    srcs = [
-        "error.go",
-        "middleware.go",
-        "util.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/server",
+    srcs = ["error.go"],
+    importpath = "github.com/OffchainLabs/prysm/v6/api/server",
     visibility = ["//visibility:public"],
-    deps = [
-        "@com_github_gorilla_mux//:go_default_library",
-        "@com_github_rs_cors//:go_default_library",
-    ],
 )
 
 go_test(
     name = "go_default_test",
-    srcs = [
-        "error_test.go",
-        "middleware_test.go",
-        "util_test.go",
-    ],
+    srcs = ["error_test.go"],
     embed = [":go_default_library"],
-    deps = [
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-    ],
+    deps = ["//testing/assert:go_default_library"],
 )

api/server/error.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 )
@@ -15,7 +16,8 @@ type DecodeError struct {
 // NewDecodeError wraps an error (either the initial decoding error or another DecodeError).
 // The current field that failed decoding must be passed in.
 func NewDecodeError(err error, field string) *DecodeError {
-	de, ok := err.(*DecodeError)
+	var de *DecodeError
+	ok := errors.As(err, &de)
 	if ok {
 		return &DecodeError{path: append([]string{field}, de.path...), err: de.err}
 	}

api/server/error_test.go

@@ -4,7 +4,7 @@ import (
 	"errors"
 	"testing"
 
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
 )
 
 func TestDecodeError(t *testing.T) {

api/server/httprest/BUILD.bazel

@@ -0,0 +1,31 @@
+load("@prysm//tools/go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "log.go",
+        "options.go",
+        "server.go",
+    ],
+    importpath = "github.com/OffchainLabs/prysm/v6/api/server/httprest",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//api/server/middleware:go_default_library",
+        "//runtime:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
+        "@com_github_sirupsen_logrus//:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["server_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "//cmd/beacon-chain/flags:go_default_library",
+        "//testing/assert:go_default_library",
+        "//testing/require:go_default_library",
+        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
+        "@com_github_urfave_cli_v2//:go_default_library",
+    ],
+)

api/server/httprest/log.go

@@ -0,0 +1,5 @@
+package httprest
+
+import "github.com/sirupsen/logrus"
+
+var log = logrus.WithField("prefix", "httprest")

api/server/httprest/options.go

@@ -0,0 +1,44 @@
+package httprest
+
+import (
+	"time"
+
+	"net/http"
+
+	"github.com/OffchainLabs/prysm/v6/api/server/middleware"
+)
+
+// Option is a http rest server functional parameter type.
+type Option func(g *Server) error
+
+// WithMiddlewares sets the list of middlewares to be applied on routes.
+func WithMiddlewares(mw []middleware.Middleware) Option {
+	return func(g *Server) error {
+		g.cfg.middlewares = mw
+		return nil
+	}
+}
+
+// WithHTTPAddr sets the full address ( host and port ) of the server.
+func WithHTTPAddr(addr string) Option {
+	return func(g *Server) error {
+		g.cfg.httpAddr = addr
+		return nil
+	}
+}
+
+// WithRouter sets the internal router of the server, this is required.
+func WithRouter(r *http.ServeMux) Option {
+	return func(g *Server) error {
+		g.cfg.router = r
+		return nil
+	}
+}
+
+// WithTimeout allows changing the timeout value for API calls.
+func WithTimeout(duration time.Duration) Option {
+	return func(g *Server) error {
+		g.cfg.timeout = duration
+		return nil
+	}
+}

api/server/httprest/server.go

@@ -0,0 +1,101 @@
+package httprest
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"github.com/OffchainLabs/prysm/v6/api/server/middleware"
+	"github.com/OffchainLabs/prysm/v6/runtime"
+	"github.com/pkg/errors"
+)
+
+var _ runtime.Service = (*Server)(nil)
+
+// Config parameters for setting up the http-rest service.
+type config struct {
+	httpAddr    string
+	middlewares []middleware.Middleware
+	router      http.Handler
+	timeout     time.Duration
+}
+
+// Server serves HTTP traffic.
+type Server struct {
+	cfg          *config
+	server       *http.Server
+	cancel       context.CancelFunc
+	ctx          context.Context
+	startFailure error
+}
+
+// New returns a new instance of the Server.
+func New(ctx context.Context, opts ...Option) (*Server, error) {
+	g := &Server{
+		ctx: ctx,
+		cfg: &config{},
+	}
+	for _, opt := range opts {
+		if err := opt(g); err != nil {
+			return nil, err
+		}
+	}
+	if g.cfg.router == nil {
+		return nil, errors.New("router option not configured")
+	}
+	var handler http.Handler
+	defaultReadHeaderTimeout := time.Second
+	handler = middleware.MiddlewareChain(g.cfg.router, g.cfg.middlewares)
+	if g.cfg.timeout > 0*time.Second {
+		defaultReadHeaderTimeout = g.cfg.timeout
+		handler = http.TimeoutHandler(handler, g.cfg.timeout, "request timed out")
+	}
+	g.server = &http.Server{
+		Addr:              g.cfg.httpAddr,
+		Handler:           handler,
+		ReadHeaderTimeout: defaultReadHeaderTimeout,
+	}
+
+	return g, nil
+}
+
+// Start the http rest service.
+func (g *Server) Start() {
+	g.ctx, g.cancel = context.WithCancel(g.ctx)
+
+	go func() {
+		log.WithField("address", g.cfg.httpAddr).Info("Starting HTTP server")
+		if err := g.server.ListenAndServe(); err != http.ErrServerClosed {
+			log.WithError(err).Error("Failed to start HTTP server")
+			g.startFailure = err
+			return
+		}
+	}()
+}
+
+// Status of the HTTP server. Returns an error if this service is unhealthy.
+func (g *Server) Status() error {
+	if g.startFailure != nil {
+		return g.startFailure
+	}
+	return nil
+}
+
+// Stop the HTTP server with a graceful shutdown.
+func (g *Server) Stop() error {
+	if g.server != nil {
+		shutdownCtx, shutdownCancel := context.WithTimeout(g.ctx, 2*time.Second)
+		defer shutdownCancel()
+		if err := g.server.Shutdown(shutdownCtx); err != nil {
+			if errors.Is(err, context.DeadlineExceeded) {
+				log.Warn("Existing connections terminated")
+			} else {
+				log.WithError(err).Error("Failed to gracefully shut down server")
+			}
+		}
+	}
+	if g.cancel != nil {
+		g.cancel()
+	}
+	return nil
+}

api/server/httprest/server_test.go

@@ -0,0 +1,71 @@
+package httprest
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+	logTest "github.com/sirupsen/logrus/hooks/test"
+	"github.com/urfave/cli/v2"
+)
+
+func TestServer_StartStop(t *testing.T) {
+	hook := logTest.NewGlobal()
+
+	app := cli.App{}
+	set := flag.NewFlagSet("test", 0)
+	ctx := cli.NewContext(&app, set, nil)
+
+	port := ctx.Int(flags.HTTPServerPort.Name)
+	portStr := fmt.Sprintf("%d", port) // Convert port to string
+	host := ctx.String(flags.HTTPServerHost.Name)
+	address := net.JoinHostPort(host, portStr)
+	handler := http.NewServeMux()
+	opts := []Option{
+		WithHTTPAddr(address),
+		WithRouter(handler),
+	}
+
+	g, err := New(context.Background(), opts...)
+	require.NoError(t, err)
+
+	g.Start()
+	go func() {
+		require.LogsContain(t, hook, "Starting HTTP server")
+		require.LogsDoNotContain(t, hook, "Starting API middleware")
+	}()
+	err = g.Stop()
+	require.NoError(t, err)
+}
+
+func TestServer_NilHandler_NotFoundHandlerRegistered(t *testing.T) {
+	app := cli.App{}
+	set := flag.NewFlagSet("test", 0)
+	ctx := cli.NewContext(&app, set, nil)
+
+	handler := http.NewServeMux()
+	port := ctx.Int(flags.HTTPServerPort.Name)
+	portStr := fmt.Sprintf("%d", port) // Convert port to string
+	host := ctx.String(flags.HTTPServerHost.Name)
+	address := net.JoinHostPort(host, portStr)
+
+	opts := []Option{
+		WithHTTPAddr(address),
+		WithRouter(handler),
+	}
+
+	g, err := New(context.Background(), opts...)
+	require.NoError(t, err)
+
+	writer := httptest.NewRecorder()
+	g.cfg.router.ServeHTTP(writer, &http.Request{Method: "GET", Host: "localhost", URL: &url.URL{Path: "/foo"}})
+	assert.Equal(t, http.StatusNotFound, writer.Code)
+}

api/server/middleware.go

@@ -1,32 +0,0 @@
-package server
-
-import (
-	"net/http"
-
-	"github.com/gorilla/mux"
-	"github.com/rs/cors"
-)
-
-// NormalizeQueryValuesHandler normalizes an input query of "key=value1,value2,value3" to "key=value1&key=value2&key=value3"
-func NormalizeQueryValuesHandler(next http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		query := r.URL.Query()
-		NormalizeQueryValues(query)
-		r.URL.RawQuery = query.Encode()
-
-		next.ServeHTTP(w, r)
-	})
-}
-
-// CorsHandler sets the cors settings on api endpoints
-func CorsHandler(allowOrigins []string) mux.MiddlewareFunc {
-	c := cors.New(cors.Options{
-		AllowedOrigins:   allowOrigins,
-		AllowedMethods:   []string{http.MethodPost, http.MethodGet, http.MethodDelete, http.MethodOptions},
-		AllowCredentials: true,
-		MaxAge:           600,
-		AllowedHeaders:   []string{"*"},
-	})
-
-	return c.Handler
-}

api/server/middleware/BUILD.bazel

@@ -0,0 +1,26 @@
+load("@prysm//tools/go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "middleware.go",
+        "util.go",
+    ],
+    importpath = "github.com/OffchainLabs/prysm/v6/api/server/middleware",
+    visibility = ["//visibility:public"],
+    deps = ["@com_github_rs_cors//:go_default_library"],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = [
+        "middleware_test.go",
+        "util_test.go",
+    ],
+    embed = [":go_default_library"],
+    deps = [
+        "//api:go_default_library",
+        "//testing/assert:go_default_library",
+        "//testing/require:go_default_library",
+    ],
+)

api/server/middleware/middleware.go

@@ -0,0 +1,125 @@
+package middleware
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/rs/cors"
+)
+
+type Middleware func(http.Handler) http.Handler
+
+// NormalizeQueryValuesHandler normalizes an input query of "key=value1,value2,value3" to "key=value1&key=value2&key=value3"
+func NormalizeQueryValuesHandler(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		query := r.URL.Query()
+		NormalizeQueryValues(query)
+		r.URL.RawQuery = query.Encode()
+
+		next.ServeHTTP(w, r)
+	})
+}
+
+// CorsHandler sets the cors settings on api endpoints
+func CorsHandler(allowOrigins []string) Middleware {
+	c := cors.New(cors.Options{
+		AllowedOrigins:   allowOrigins,
+		AllowedMethods:   []string{http.MethodPost, http.MethodGet, http.MethodDelete, http.MethodOptions},
+		AllowCredentials: true,
+		MaxAge:           600,
+		AllowedHeaders:   []string{"*"},
+	})
+
+	return c.Handler
+}
+
+// ContentTypeHandler checks request for the appropriate media types otherwise returning a http.StatusUnsupportedMediaType error
+func ContentTypeHandler(acceptedMediaTypes []string) Middleware {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			// skip the GET request
+			if r.Method == http.MethodGet {
+				next.ServeHTTP(w, r)
+				return
+			}
+			contentType := r.Header.Get("Content-Type")
+			if contentType == "" {
+				http.Error(w, "Content-Type header is missing", http.StatusUnsupportedMediaType)
+				return
+			}
+
+			accepted := false
+			for _, acceptedType := range acceptedMediaTypes {
+				if strings.Contains(strings.TrimSpace(contentType), strings.TrimSpace(acceptedType)) {
+					accepted = true
+					break
+				}
+			}
+
+			if !accepted {
+				http.Error(w, fmt.Sprintf("Unsupported media type: %s", contentType), http.StatusUnsupportedMediaType)
+				return
+			}
+
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+// AcceptHeaderHandler checks if the client's response preference is handled
+func AcceptHeaderHandler(serverAcceptedTypes []string) Middleware {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			acceptHeader := r.Header.Get("Accept")
+			// header is optional and should skip if not provided
+			if acceptHeader == "" {
+				next.ServeHTTP(w, r)
+				return
+			}
+
+			accepted := false
+			acceptTypes := strings.Split(acceptHeader, ",")
+			// follows rules defined in https://datatracker.ietf.org/doc/html/rfc2616#section-14.1
+			for _, acceptType := range acceptTypes {
+				acceptType = strings.TrimSpace(acceptType)
+				if acceptType == "*/*" {
+					accepted = true
+					break
+				}
+				for _, serverAcceptedType := range serverAcceptedTypes {
+					if strings.HasPrefix(acceptType, serverAcceptedType) {
+						accepted = true
+						break
+					}
+					if acceptType != "/*" && strings.HasSuffix(acceptType, "/*") && strings.HasPrefix(serverAcceptedType, acceptType[:len(acceptType)-2]) {
+						accepted = true
+						break
+					}
+				}
+				if accepted {
+					break
+				}
+			}
+
+			if !accepted {
+				http.Error(w, fmt.Sprintf("Not Acceptable: %s", acceptHeader), http.StatusNotAcceptable)
+				return
+			}
+
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+func MiddlewareChain(h http.Handler, mw []Middleware) http.Handler {
+	if len(mw) < 1 {
+		return h
+	}
+
+	wrapped := h
+	for i := len(mw) - 1; i >= 0; i-- {
+		wrapped = mw[i](wrapped)
+	}
+	return wrapped
+}

api/server/middleware/middleware_test.go

@@ -0,0 +1,204 @@
+package middleware
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/api"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+)
+
+func TestNormalizeQueryValuesHandler(t *testing.T) {
+	nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, err := w.Write([]byte("next handler"))
+		require.NoError(t, err)
+	})
+
+	handler := NormalizeQueryValuesHandler(nextHandler)
+
+	tests := []struct {
+		name          string
+		inputQuery    string
+		expectedQuery string
+	}{
+		{
+			name:          "3 values",
+			inputQuery:    "key=value1,value2,value3",
+			expectedQuery: "key=value1&key=value2&key=value3", // replace with expected normalized value
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			req, err := http.NewRequest("GET", "/test?"+test.inputQuery, http.NoBody)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			rr := httptest.NewRecorder()
+			handler.ServeHTTP(rr, req)
+
+			if rr.Code != http.StatusOK {
+				t.Errorf("handler returned wrong status code: got %v want %v", rr.Code, http.StatusOK)
+			}
+
+			if req.URL.RawQuery != test.expectedQuery {
+				t.Errorf("query not normalized: got %v want %v", req.URL.RawQuery, test.expectedQuery)
+			}
+
+			if rr.Body.String() != "next handler" {
+				t.Errorf("next handler was not executed")
+			}
+		})
+	}
+}
+
+func TestContentTypeHandler(t *testing.T) {
+	acceptedMediaTypes := []string{api.JsonMediaType, api.OctetStreamMediaType}
+
+	nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, err := w.Write([]byte("next handler"))
+		require.NoError(t, err)
+	})
+
+	handler := ContentTypeHandler(acceptedMediaTypes)(nextHandler)
+
+	tests := []struct {
+		name               string
+		contentType        string
+		expectedStatusCode int
+		isGet              bool
+	}{
+		{
+			name:               "Accepted Content-Type - application/json",
+			contentType:        api.JsonMediaType,
+			expectedStatusCode: http.StatusOK,
+		},
+		{
+			name:               "Accepted Content-Type - ssz format",
+			contentType:        api.OctetStreamMediaType,
+			expectedStatusCode: http.StatusOK,
+		},
+		{
+			name:               "Unsupported Content-Type - text/plain",
+			contentType:        "text/plain",
+			expectedStatusCode: http.StatusUnsupportedMediaType,
+		},
+		{
+			name:               "Missing Content-Type",
+			contentType:        "",
+			expectedStatusCode: http.StatusUnsupportedMediaType,
+		},
+		{
+			name:               "GET request skips content type check",
+			contentType:        "",
+			expectedStatusCode: http.StatusOK,
+			isGet:              true,
+		},
+		{
+			name:               "Content type contains charset is ok",
+			contentType:        "application/json; charset=utf-8",
+			expectedStatusCode: http.StatusOK,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			httpMethod := http.MethodPost
+			if tt.isGet {
+				httpMethod = http.MethodGet
+			}
+			req := httptest.NewRequest(httpMethod, "/", nil)
+			if tt.contentType != "" {
+				req.Header.Set("Content-Type", tt.contentType)
+			}
+			rr := httptest.NewRecorder()
+
+			handler.ServeHTTP(rr, req)
+
+			if status := rr.Code; status != tt.expectedStatusCode {
+				t.Errorf("handler returned wrong status code: got %v want %v", status, tt.expectedStatusCode)
+			}
+		})
+	}
+}
+
+func TestAcceptHeaderHandler(t *testing.T) {
+	acceptedTypes := []string{"application/json", "application/octet-stream"}
+
+	nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, err := w.Write([]byte("next handler"))
+		require.NoError(t, err)
+	})
+
+	handler := AcceptHeaderHandler(acceptedTypes)(nextHandler)
+
+	tests := []struct {
+		name               string
+		acceptHeader       string
+		expectedStatusCode int
+	}{
+		{
+			name:               "Accepted Accept-Type - application/json",
+			acceptHeader:       "application/json",
+			expectedStatusCode: http.StatusOK,
+		},
+		{
+			name:               "Accepted Accept-Type - application/octet-stream",
+			acceptHeader:       "application/octet-stream",
+			expectedStatusCode: http.StatusOK,
+		},
+		{
+			name:               "Accepted Accept-Type with parameters",
+			acceptHeader:       "application/json;q=0.9, application/octet-stream;q=0.8",
+			expectedStatusCode: http.StatusOK,
+		},
+		{
+			name:               "Unsupported Accept-Type - text/plain",
+			acceptHeader:       "text/plain",
+			expectedStatusCode: http.StatusNotAcceptable,
+		},
+		{
+			name:               "Missing Accept header",
+			acceptHeader:       "",
+			expectedStatusCode: http.StatusOK,
+		},
+		{
+			name:               "*/* is accepted",
+			acceptHeader:       "*/*",
+			expectedStatusCode: http.StatusOK,
+		},
+		{
+			name:               "application/* is accepted",
+			acceptHeader:       "application/*",
+			expectedStatusCode: http.StatusOK,
+		},
+		{
+			name:               "/* is unsupported",
+			acceptHeader:       "/*",
+			expectedStatusCode: http.StatusNotAcceptable,
+		},
+		{
+			name:               "application/ is unsupported",
+			acceptHeader:       "application/",
+			expectedStatusCode: http.StatusNotAcceptable,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			req := httptest.NewRequest("GET", "/", nil)
+			if tt.acceptHeader != "" {
+				req.Header.Set("Accept", tt.acceptHeader)
+			}
+			rr := httptest.NewRecorder()
+
+			handler.ServeHTTP(rr, req)
+
+			if status := rr.Code; status != tt.expectedStatusCode {
+				t.Errorf("handler returned wrong status code: got %v want %v", status, tt.expectedStatusCode)
+			}
+		})
+	}
+}

api/server/middleware/util.go

@@ -1,4 +1,4 @@
-package server
+package middleware
 
 import (
 	"net/url"

api/server/middleware/util_test.go

@@ -1,10 +1,10 @@
-package server
+package middleware
 
 import (
 	"testing"
 
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
 )
 
 func TestNormalizeQueryValues(t *testing.T) {

api/server/middleware_test.go

@@ -1,54 +0,0 @@
-package server
-
-import (
-	"net/http"
-	"net/http/httptest"
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-)
-
-func TestNormalizeQueryValuesHandler(t *testing.T) {
-	nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		_, err := w.Write([]byte("next handler"))
-		require.NoError(t, err)
-	})
-
-	handler := NormalizeQueryValuesHandler(nextHandler)
-
-	tests := []struct {
-		name          string
-		inputQuery    string
-		expectedQuery string
-	}{
-		{
-			name:          "3 values",
-			inputQuery:    "key=value1,value2,value3",
-			expectedQuery: "key=value1&key=value2&key=value3", // replace with expected normalized value
-		},
-	}
-
-	for _, test := range tests {
-		t.Run(test.name, func(t *testing.T) {
-			req, err := http.NewRequest("GET", "/test?"+test.inputQuery, nil)
-			if err != nil {
-				t.Fatal(err)
-			}
-
-			rr := httptest.NewRecorder()
-			handler.ServeHTTP(rr, req)
-
-			if rr.Code != http.StatusOK {
-				t.Errorf("handler returned wrong status code: got %v want %v", rr.Code, http.StatusOK)
-			}
-
-			if req.URL.RawQuery != test.expectedQuery {
-				t.Errorf("query not normalized: got %v want %v", req.URL.RawQuery, test.expectedQuery)
-			}
-
-			if rr.Body.String() != "next handler" {
-				t.Errorf("next handler was not executed")
-			}
-		})
-	}
-}

api/server/structs/BUILD.bazel

@@ -4,8 +4,12 @@ go_library(
     name = "go_default_library",
     srcs = [
         "block.go",
+        "block_execution.go",
         "conversions.go",
+        "conversions_blob.go",
         "conversions_block.go",
+        "conversions_block_execution.go",
+        "conversions_lightclient.go",
         "conversions_state.go",
         "endpoints_beacon.go",
         "endpoints_blob.go",
@@ -20,19 +24,23 @@ go_library(
         "other.go",
         "state.go",
     ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/server/structs",
+    importpath = "github.com/OffchainLabs/prysm/v6/api/server/structs",
     visibility = ["//visibility:public"],
     deps = [
         "//api/server:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//config/fieldparams:go_default_library",
+        "//config/params:go_default_library",
+        "//consensus-types/interfaces:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//consensus-types/validator:go_default_library",
         "//container/slice:go_default_library",
         "//encoding/bytesutil:go_default_library",
         "//math:go_default_library",
         "//proto/engine/v1:go_default_library",
+        "//proto/eth/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
+        "//runtime/version:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
@@ -41,10 +49,16 @@ go_library(
 
 go_test(
     name = "go_default_test",
-    srcs = ["conversions_test.go"],
+    srcs = [
+        "conversions_block_execution_test.go",
+        "conversions_test.go",
+    ],
     embed = [":go_default_library"],
     deps = [
+        "//proto/engine/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//testing/require:go_default_library",
+        "@com_github_ethereum_go_ethereum//common:go_default_library",
+        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
     ],
 )

api/server/structs/block.go

@@ -1,10 +1,38 @@
 package structs
 
+import "encoding/json"
+
+// MessageJsoner describes a signed consensus type wrapper that can return the `.Message` field in a json envelope
+// encoded as a []byte, for use as a json.RawMessage value when encoding the outer envelope.
+type MessageJsoner interface {
+	MessageRawJson() ([]byte, error)
+}
+
+// SignedMessageJsoner embeds MessageJsoner and adds a method to also retrieve the Signature field as a string.
+type SignedMessageJsoner interface {
+	MessageJsoner
+	SigString() string
+}
+
+// ----------------------------------------------------------------------------
+// Phase 0
+// ----------------------------------------------------------------------------
+
 type SignedBeaconBlock struct {
 	Message   *BeaconBlock `json:"message"`
 	Signature string       `json:"signature"`
 }
 
+var _ SignedMessageJsoner = &SignedBeaconBlock{}
+
+func (s *SignedBeaconBlock) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
+}
+
+func (s *SignedBeaconBlock) SigString() string {
+	return s.Signature
+}
+
 type BeaconBlock struct {
 	Slot          string           `json:"slot"`
 	ProposerIndex string           `json:"proposer_index"`
@@ -24,11 +52,44 @@ type BeaconBlockBody struct {
 	VoluntaryExits    []*SignedVoluntaryExit `json:"voluntary_exits"`
 }
 
+type SignedBeaconBlockHeaderContainer struct {
+	Header    *SignedBeaconBlockHeader `json:"header"`
+	Root      string                   `json:"root"`
+	Canonical bool                     `json:"canonical"`
+}
+
+type SignedBeaconBlockHeader struct {
+	Message   *BeaconBlockHeader `json:"message"`
+	Signature string             `json:"signature"`
+}
+
+type BeaconBlockHeader struct {
+	Slot          string `json:"slot"`
+	ProposerIndex string `json:"proposer_index"`
+	ParentRoot    string `json:"parent_root"`
+	StateRoot     string `json:"state_root"`
+	BodyRoot      string `json:"body_root"`
+}
+
+// ----------------------------------------------------------------------------
+// Altair
+// ----------------------------------------------------------------------------
+
 type SignedBeaconBlockAltair struct {
 	Message   *BeaconBlockAltair `json:"message"`
 	Signature string             `json:"signature"`
 }
 
+var _ SignedMessageJsoner = &SignedBeaconBlockAltair{}
+
+func (s *SignedBeaconBlockAltair) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
+}
+
+func (s *SignedBeaconBlockAltair) SigString() string {
+	return s.Signature
+}
+
 type BeaconBlockAltair struct {
 	Slot          string                 `json:"slot"`
 	ProposerIndex string                 `json:"proposer_index"`
@@ -49,11 +110,25 @@ type BeaconBlockBodyAltair struct {
 	SyncAggregate     *SyncAggregate         `json:"sync_aggregate"`
 }
 
+// ----------------------------------------------------------------------------
+// Bellatrix
+// ----------------------------------------------------------------------------
+
 type SignedBeaconBlockBellatrix struct {
 	Message   *BeaconBlockBellatrix `json:"message"`
 	Signature string                `json:"signature"`
 }
 
+var _ SignedMessageJsoner = &SignedBeaconBlockBellatrix{}
+
+func (s *SignedBeaconBlockBellatrix) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
+}
+
+func (s *SignedBeaconBlockBellatrix) SigString() string {
+	return s.Signature
+}
+
 type BeaconBlockBellatrix struct {
 	Slot          string                    `json:"slot"`
 	ProposerIndex string                    `json:"proposer_index"`
@@ -80,6 +155,16 @@ type SignedBlindedBeaconBlockBellatrix struct {
 	Signature string                       `json:"signature"`
 }
 
+var _ SignedMessageJsoner = &SignedBlindedBeaconBlockBellatrix{}
+
+func (s *SignedBlindedBeaconBlockBellatrix) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
+}
+
+func (s *SignedBlindedBeaconBlockBellatrix) SigString() string {
+	return s.Signature
+}
+
 type BlindedBeaconBlockBellatrix struct {
 	Slot          string                           `json:"slot"`
 	ProposerIndex string                           `json:"proposer_index"`
@@ -101,11 +186,25 @@ type BlindedBeaconBlockBodyBellatrix struct {
 	ExecutionPayloadHeader *ExecutionPayloadHeader `json:"execution_payload_header"`
 }
 
+// ----------------------------------------------------------------------------
+// Capella
+// ----------------------------------------------------------------------------
+
 type SignedBeaconBlockCapella struct {
 	Message   *BeaconBlockCapella `json:"message"`
 	Signature string              `json:"signature"`
 }
 
+var _ SignedMessageJsoner = &SignedBeaconBlockCapella{}
+
+func (s *SignedBeaconBlockCapella) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
+}
+
+func (s *SignedBeaconBlockCapella) SigString() string {
+	return s.Signature
+}
+
 type BeaconBlockCapella struct {
 	Slot          string                  `json:"slot"`
 	ProposerIndex string                  `json:"proposer_index"`
@@ -133,6 +232,16 @@ type SignedBlindedBeaconBlockCapella struct {
 	Signature string                     `json:"signature"`
 }
 
+var _ SignedMessageJsoner = &SignedBlindedBeaconBlockCapella{}
+
+func (s *SignedBlindedBeaconBlockCapella) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
+}
+
+func (s *SignedBlindedBeaconBlockCapella) SigString() string {
+	return s.Signature
+}
+
 type BlindedBeaconBlockCapella struct {
 	Slot          string                         `json:"slot"`
 	ProposerIndex string                         `json:"proposer_index"`
@@ -155,6 +264,10 @@ type BlindedBeaconBlockBodyCapella struct {
 	BLSToExecutionChanges  []*SignedBLSToExecutionChange  `json:"bls_to_execution_changes"`
 }
 
+// ----------------------------------------------------------------------------
+// Deneb
+// ----------------------------------------------------------------------------
+
 type SignedBeaconBlockContentsDeneb struct {
 	SignedBlock *SignedBeaconBlockDeneb `json:"signed_block"`
 	KzgProofs   []string                `json:"kzg_proofs"`
@@ -172,6 +285,16 @@ type SignedBeaconBlockDeneb struct {
 	Signature string            `json:"signature"`
 }
 
+var _ SignedMessageJsoner = &SignedBeaconBlockDeneb{}
+
+func (s *SignedBeaconBlockDeneb) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
+}
+
+func (s *SignedBeaconBlockDeneb) SigString() string {
+	return s.Signature
+}
+
 type BeaconBlockDeneb struct {
 	Slot          string                `json:"slot"`
 	ProposerIndex string                `json:"proposer_index"`
@@ -208,6 +331,16 @@ type SignedBlindedBeaconBlockDeneb struct {
 	Signature string                   `json:"signature"`
 }
 
+var _ SignedMessageJsoner = &SignedBlindedBeaconBlockDeneb{}
+
+func (s *SignedBlindedBeaconBlockDeneb) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
+}
+
+func (s *SignedBlindedBeaconBlockDeneb) SigString() string {
+	return s.Signature
+}
+
 type BlindedBeaconBlockBodyDeneb struct {
 	RandaoReveal           string                        `json:"randao_reveal"`
 	Eth1Data               *Eth1Data                     `json:"eth1_data"`
@@ -223,131 +356,150 @@ type BlindedBeaconBlockBodyDeneb struct {
 	BlobKzgCommitments     []string                      `json:"blob_kzg_commitments"`
 }
 
-type SignedBeaconBlockHeaderContainer struct {
-	Header    *SignedBeaconBlockHeader `json:"header"`
-	Root      string                   `json:"root"`
-	Canonical bool                     `json:"canonical"`
+// ----------------------------------------------------------------------------
+// Electra
+// ----------------------------------------------------------------------------
+
+type SignedBeaconBlockContentsElectra struct {
+	SignedBlock *SignedBeaconBlockElectra `json:"signed_block"`
+	KzgProofs   []string                  `json:"kzg_proofs"`
+	Blobs       []string                  `json:"blobs"`
 }
 
-type SignedBeaconBlockHeader struct {
-	Message   *BeaconBlockHeader `json:"message"`
-	Signature string             `json:"signature"`
+type BeaconBlockContentsElectra struct {
+	Block     *BeaconBlockElectra `json:"block"`
+	KzgProofs []string            `json:"kzg_proofs"`
+	Blobs     []string            `json:"blobs"`
 }
 
-type BeaconBlockHeader struct {
-	Slot          string `json:"slot"`
-	ProposerIndex string `json:"proposer_index"`
-	ParentRoot    string `json:"parent_root"`
-	StateRoot     string `json:"state_root"`
-	BodyRoot      string `json:"body_root"`
+type SignedBeaconBlockElectra struct {
+	Message   *BeaconBlockElectra `json:"message"`
+	Signature string              `json:"signature"`
 }
 
-type ExecutionPayload struct {
-	ParentHash    string   `json:"parent_hash"`
-	FeeRecipient  string   `json:"fee_recipient"`
-	StateRoot     string   `json:"state_root"`
-	ReceiptsRoot  string   `json:"receipts_root"`
-	LogsBloom     string   `json:"logs_bloom"`
-	PrevRandao    string   `json:"prev_randao"`
-	BlockNumber   string   `json:"block_number"`
-	GasLimit      string   `json:"gas_limit"`
-	GasUsed       string   `json:"gas_used"`
-	Timestamp     string   `json:"timestamp"`
-	ExtraData     string   `json:"extra_data"`
-	BaseFeePerGas string   `json:"base_fee_per_gas"`
-	BlockHash     string   `json:"block_hash"`
-	Transactions  []string `json:"transactions"`
+var _ SignedMessageJsoner = &SignedBeaconBlockElectra{}
+
+func (s *SignedBeaconBlockElectra) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
 }
 
-type ExecutionPayloadHeader struct {
-	ParentHash       string `json:"parent_hash"`
-	FeeRecipient     string `json:"fee_recipient"`
-	StateRoot        string `json:"state_root"`
-	ReceiptsRoot     string `json:"receipts_root"`
-	LogsBloom        string `json:"logs_bloom"`
-	PrevRandao       string `json:"prev_randao"`
-	BlockNumber      string `json:"block_number"`
-	GasLimit         string `json:"gas_limit"`
-	GasUsed          string `json:"gas_used"`
-	Timestamp        string `json:"timestamp"`
-	ExtraData        string `json:"extra_data"`
-	BaseFeePerGas    string `json:"base_fee_per_gas"`
-	BlockHash        string `json:"block_hash"`
-	TransactionsRoot string `json:"transactions_root"`
+func (s *SignedBeaconBlockElectra) SigString() string {
+	return s.Signature
 }
 
-type ExecutionPayloadCapella struct {
-	ParentHash    string        `json:"parent_hash"`
-	FeeRecipient  string        `json:"fee_recipient"`
-	StateRoot     string        `json:"state_root"`
-	ReceiptsRoot  string        `json:"receipts_root"`
-	LogsBloom     string        `json:"logs_bloom"`
-	PrevRandao    string        `json:"prev_randao"`
-	BlockNumber   string        `json:"block_number"`
-	GasLimit      string        `json:"gas_limit"`
-	GasUsed       string        `json:"gas_used"`
-	Timestamp     string        `json:"timestamp"`
-	ExtraData     string        `json:"extra_data"`
-	BaseFeePerGas string        `json:"base_fee_per_gas"`
-	BlockHash     string        `json:"block_hash"`
-	Transactions  []string      `json:"transactions"`
-	Withdrawals   []*Withdrawal `json:"withdrawals"`
+type BeaconBlockElectra struct {
+	Slot          string                  `json:"slot"`
+	ProposerIndex string                  `json:"proposer_index"`
+	ParentRoot    string                  `json:"parent_root"`
+	StateRoot     string                  `json:"state_root"`
+	Body          *BeaconBlockBodyElectra `json:"body"`
 }
 
-type ExecutionPayloadHeaderCapella struct {
-	ParentHash       string `json:"parent_hash"`
-	FeeRecipient     string `json:"fee_recipient"`
-	StateRoot        string `json:"state_root"`
-	ReceiptsRoot     string `json:"receipts_root"`
-	LogsBloom        string `json:"logs_bloom"`
-	PrevRandao       string `json:"prev_randao"`
-	BlockNumber      string `json:"block_number"`
-	GasLimit         string `json:"gas_limit"`
-	GasUsed          string `json:"gas_used"`
-	Timestamp        string `json:"timestamp"`
-	ExtraData        string `json:"extra_data"`
-	BaseFeePerGas    string `json:"base_fee_per_gas"`
-	BlockHash        string `json:"block_hash"`
-	TransactionsRoot string `json:"transactions_root"`
-	WithdrawalsRoot  string `json:"withdrawals_root"`
+type BeaconBlockBodyElectra struct {
+	RandaoReveal          string                        `json:"randao_reveal"`
+	Eth1Data              *Eth1Data                     `json:"eth1_data"`
+	Graffiti              string                        `json:"graffiti"`
+	ProposerSlashings     []*ProposerSlashing           `json:"proposer_slashings"`
+	AttesterSlashings     []*AttesterSlashingElectra    `json:"attester_slashings"`
+	Attestations          []*AttestationElectra         `json:"attestations"`
+	Deposits              []*Deposit                    `json:"deposits"`
+	VoluntaryExits        []*SignedVoluntaryExit        `json:"voluntary_exits"`
+	SyncAggregate         *SyncAggregate                `json:"sync_aggregate"`
+	ExecutionPayload      *ExecutionPayloadDeneb        `json:"execution_payload"`
+	BLSToExecutionChanges []*SignedBLSToExecutionChange `json:"bls_to_execution_changes"`
+	BlobKzgCommitments    []string                      `json:"blob_kzg_commitments"`
+	ExecutionRequests     *ExecutionRequests            `json:"execution_requests"`
 }
 
-type ExecutionPayloadDeneb struct {
-	ParentHash    string        `json:"parent_hash"`
-	FeeRecipient  string        `json:"fee_recipient"`
-	StateRoot     string        `json:"state_root"`
-	ReceiptsRoot  string        `json:"receipts_root"`
-	LogsBloom     string        `json:"logs_bloom"`
-	PrevRandao    string        `json:"prev_randao"`
-	BlockNumber   string        `json:"block_number"`
-	GasLimit      string        `json:"gas_limit"`
-	GasUsed       string        `json:"gas_used"`
-	Timestamp     string        `json:"timestamp"`
-	ExtraData     string        `json:"extra_data"`
-	BaseFeePerGas string        `json:"base_fee_per_gas"`
-	BlockHash     string        `json:"block_hash"`
-	Transactions  []string      `json:"transactions"`
-	Withdrawals   []*Withdrawal `json:"withdrawals"`
-	BlobGasUsed   string        `json:"blob_gas_used"`
-	ExcessBlobGas string        `json:"excess_blob_gas"`
+type BlindedBeaconBlockElectra struct {
+	Slot          string                         `json:"slot"`
+	ProposerIndex string                         `json:"proposer_index"`
+	ParentRoot    string                         `json:"parent_root"`
+	StateRoot     string                         `json:"state_root"`
+	Body          *BlindedBeaconBlockBodyElectra `json:"body"`
 }
 
-type ExecutionPayloadHeaderDeneb struct {
-	ParentHash       string `json:"parent_hash"`
-	FeeRecipient     string `json:"fee_recipient"`
-	StateRoot        string `json:"state_root"`
-	ReceiptsRoot     string `json:"receipts_root"`
-	LogsBloom        string `json:"logs_bloom"`
-	PrevRandao       string `json:"prev_randao"`
-	BlockNumber      string `json:"block_number"`
-	GasLimit         string `json:"gas_limit"`
-	GasUsed          string `json:"gas_used"`
-	Timestamp        string `json:"timestamp"`
-	ExtraData        string `json:"extra_data"`
-	BaseFeePerGas    string `json:"base_fee_per_gas"`
-	BlockHash        string `json:"block_hash"`
-	TransactionsRoot string `json:"transactions_root"`
-	WithdrawalsRoot  string `json:"withdrawals_root"`
-	BlobGasUsed      string `json:"blob_gas_used"`
-	ExcessBlobGas    string `json:"excess_blob_gas"`
+type SignedBlindedBeaconBlockElectra struct {
+	Message   *BlindedBeaconBlockElectra `json:"message"`
+	Signature string                     `json:"signature"`
+}
+
+var _ SignedMessageJsoner = &SignedBlindedBeaconBlockElectra{}
+
+func (s *SignedBlindedBeaconBlockElectra) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
+}
+
+func (s *SignedBlindedBeaconBlockElectra) SigString() string {
+	return s.Signature
+}
+
+type BlindedBeaconBlockBodyElectra struct {
+	RandaoReveal           string                        `json:"randao_reveal"`
+	Eth1Data               *Eth1Data                     `json:"eth1_data"`
+	Graffiti               string                        `json:"graffiti"`
+	ProposerSlashings      []*ProposerSlashing           `json:"proposer_slashings"`
+	AttesterSlashings      []*AttesterSlashingElectra    `json:"attester_slashings"`
+	Attestations           []*AttestationElectra         `json:"attestations"`
+	Deposits               []*Deposit                    `json:"deposits"`
+	VoluntaryExits         []*SignedVoluntaryExit        `json:"voluntary_exits"`
+	SyncAggregate          *SyncAggregate                `json:"sync_aggregate"`
+	ExecutionPayloadHeader *ExecutionPayloadHeaderDeneb  `json:"execution_payload_header"`
+	BLSToExecutionChanges  []*SignedBLSToExecutionChange `json:"bls_to_execution_changes"`
+	BlobKzgCommitments     []string                      `json:"blob_kzg_commitments"`
+	ExecutionRequests      *ExecutionRequests            `json:"execution_requests"`
+}
+
+// ----------------------------------------------------------------------------
+// Fulu
+// ----------------------------------------------------------------------------
+
+type SignedBeaconBlockContentsFulu struct {
+	SignedBlock *SignedBeaconBlockFulu `json:"signed_block"`
+	KzgProofs   []string               `json:"kzg_proofs"`
+	Blobs       []string               `json:"blobs"`
+}
+
+type BeaconBlockContentsFulu struct {
+	Block     *BeaconBlockElectra `json:"block"`
+	KzgProofs []string            `json:"kzg_proofs"`
+	Blobs     []string            `json:"blobs"`
+}
+
+type SignedBeaconBlockFulu struct {
+	Message   *BeaconBlockElectra `json:"message"`
+	Signature string              `json:"signature"`
+}
+
+var _ SignedMessageJsoner = &SignedBeaconBlockFulu{}
+
+func (s *SignedBeaconBlockFulu) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
+}
+
+func (s *SignedBeaconBlockFulu) SigString() string {
+	return s.Signature
+}
+
+type BlindedBeaconBlockFulu struct {
+	Slot          string                         `json:"slot"`
+	ProposerIndex string                         `json:"proposer_index"`
+	ParentRoot    string                         `json:"parent_root"`
+	StateRoot     string                         `json:"state_root"`
+	Body          *BlindedBeaconBlockBodyElectra `json:"body"`
+}
+
+type SignedBlindedBeaconBlockFulu struct {
+	Message   *BlindedBeaconBlockFulu `json:"message"`
+	Signature string                  `json:"signature"`
+}
+
+var _ SignedMessageJsoner = &SignedBlindedBeaconBlockFulu{}
+
+func (s *SignedBlindedBeaconBlockFulu) MessageRawJson() ([]byte, error) {
+	return json.Marshal(s.Message)
+}
+
+func (s *SignedBlindedBeaconBlockFulu) SigString() string {
+	return s.Signature
 }

api/server/structs/block_execution.go

@@ -0,0 +1,157 @@
+package structs
+
+// ----------------------------------------------------------------------------
+// Bellatrix
+// ----------------------------------------------------------------------------
+
+type ExecutionPayload struct {
+	ParentHash    string   `json:"parent_hash"`
+	FeeRecipient  string   `json:"fee_recipient"`
+	StateRoot     string   `json:"state_root"`
+	ReceiptsRoot  string   `json:"receipts_root"`
+	LogsBloom     string   `json:"logs_bloom"`
+	PrevRandao    string   `json:"prev_randao"`
+	BlockNumber   string   `json:"block_number"`
+	GasLimit      string   `json:"gas_limit"`
+	GasUsed       string   `json:"gas_used"`
+	Timestamp     string   `json:"timestamp"`
+	ExtraData     string   `json:"extra_data"`
+	BaseFeePerGas string   `json:"base_fee_per_gas"`
+	BlockHash     string   `json:"block_hash"`
+	Transactions  []string `json:"transactions"`
+}
+
+type ExecutionPayloadHeader struct {
+	ParentHash       string `json:"parent_hash"`
+	FeeRecipient     string `json:"fee_recipient"`
+	StateRoot        string `json:"state_root"`
+	ReceiptsRoot     string `json:"receipts_root"`
+	LogsBloom        string `json:"logs_bloom"`
+	PrevRandao       string `json:"prev_randao"`
+	BlockNumber      string `json:"block_number"`
+	GasLimit         string `json:"gas_limit"`
+	GasUsed          string `json:"gas_used"`
+	Timestamp        string `json:"timestamp"`
+	ExtraData        string `json:"extra_data"`
+	BaseFeePerGas    string `json:"base_fee_per_gas"`
+	BlockHash        string `json:"block_hash"`
+	TransactionsRoot string `json:"transactions_root"`
+}
+
+// ----------------------------------------------------------------------------
+// Capella
+// ----------------------------------------------------------------------------
+
+type ExecutionPayloadCapella struct {
+	ParentHash    string        `json:"parent_hash"`
+	FeeRecipient  string        `json:"fee_recipient"`
+	StateRoot     string        `json:"state_root"`
+	ReceiptsRoot  string        `json:"receipts_root"`
+	LogsBloom     string        `json:"logs_bloom"`
+	PrevRandao    string        `json:"prev_randao"`
+	BlockNumber   string        `json:"block_number"`
+	GasLimit      string        `json:"gas_limit"`
+	GasUsed       string        `json:"gas_used"`
+	Timestamp     string        `json:"timestamp"`
+	ExtraData     string        `json:"extra_data"`
+	BaseFeePerGas string        `json:"base_fee_per_gas"`
+	BlockHash     string        `json:"block_hash"`
+	Transactions  []string      `json:"transactions"`
+	Withdrawals   []*Withdrawal `json:"withdrawals"`
+}
+
+type ExecutionPayloadHeaderCapella struct {
+	ParentHash       string `json:"parent_hash"`
+	FeeRecipient     string `json:"fee_recipient"`
+	StateRoot        string `json:"state_root"`
+	ReceiptsRoot     string `json:"receipts_root"`
+	LogsBloom        string `json:"logs_bloom"`
+	PrevRandao       string `json:"prev_randao"`
+	BlockNumber      string `json:"block_number"`
+	GasLimit         string `json:"gas_limit"`
+	GasUsed          string `json:"gas_used"`
+	Timestamp        string `json:"timestamp"`
+	ExtraData        string `json:"extra_data"`
+	BaseFeePerGas    string `json:"base_fee_per_gas"`
+	BlockHash        string `json:"block_hash"`
+	TransactionsRoot string `json:"transactions_root"`
+	WithdrawalsRoot  string `json:"withdrawals_root"`
+}
+
+// ----------------------------------------------------------------------------
+// Deneb
+// ----------------------------------------------------------------------------
+
+type ExecutionPayloadDeneb struct {
+	ParentHash    string        `json:"parent_hash"`
+	FeeRecipient  string        `json:"fee_recipient"`
+	StateRoot     string        `json:"state_root"`
+	ReceiptsRoot  string        `json:"receipts_root"`
+	LogsBloom     string        `json:"logs_bloom"`
+	PrevRandao    string        `json:"prev_randao"`
+	BlockNumber   string        `json:"block_number"`
+	GasLimit      string        `json:"gas_limit"`
+	GasUsed       string        `json:"gas_used"`
+	Timestamp     string        `json:"timestamp"`
+	ExtraData     string        `json:"extra_data"`
+	BaseFeePerGas string        `json:"base_fee_per_gas"`
+	BlockHash     string        `json:"block_hash"`
+	Transactions  []string      `json:"transactions"`
+	Withdrawals   []*Withdrawal `json:"withdrawals"`
+	BlobGasUsed   string        `json:"blob_gas_used"`
+	ExcessBlobGas string        `json:"excess_blob_gas"`
+}
+
+type ExecutionPayloadHeaderDeneb struct {
+	ParentHash       string `json:"parent_hash"`
+	FeeRecipient     string `json:"fee_recipient"`
+	StateRoot        string `json:"state_root"`
+	ReceiptsRoot     string `json:"receipts_root"`
+	LogsBloom        string `json:"logs_bloom"`
+	PrevRandao       string `json:"prev_randao"`
+	BlockNumber      string `json:"block_number"`
+	GasLimit         string `json:"gas_limit"`
+	GasUsed          string `json:"gas_used"`
+	Timestamp        string `json:"timestamp"`
+	ExtraData        string `json:"extra_data"`
+	BaseFeePerGas    string `json:"base_fee_per_gas"`
+	BlockHash        string `json:"block_hash"`
+	TransactionsRoot string `json:"transactions_root"`
+	WithdrawalsRoot  string `json:"withdrawals_root"`
+	BlobGasUsed      string `json:"blob_gas_used"`
+	ExcessBlobGas    string `json:"excess_blob_gas"`
+}
+
+// ----------------------------------------------------------------------------
+// Electra
+// ----------------------------------------------------------------------------
+
+type ExecutionRequests struct {
+	Deposits       []*DepositRequest       `json:"deposits"`
+	Withdrawals    []*WithdrawalRequest    `json:"withdrawals"`
+	Consolidations []*ConsolidationRequest `json:"consolidations"`
+}
+
+type DepositRequest struct {
+	Pubkey                string `json:"pubkey"`
+	WithdrawalCredentials string `json:"withdrawal_credentials"`
+	Amount                string `json:"amount"`
+	Signature             string `json:"signature"`
+	Index                 string `json:"index"`
+}
+
+type WithdrawalRequest struct {
+	SourceAddress   string `json:"source_address"`
+	ValidatorPubkey string `json:"validator_pubkey"`
+	Amount          string `json:"amount"`
+}
+
+type ConsolidationRequest struct {
+	SourceAddress string `json:"source_address"`
+	SourcePubkey  string `json:"source_pubkey"`
+	TargetPubkey  string `json:"target_pubkey"`
+}
+
+// ----------------------------------------------------------------------------
+// Fulu
+// ----------------------------------------------------------------------------

api/server/structs/conversions.go

@@ -4,19 +4,20 @@ import (
 	"fmt"
 	"strconv"
 
+	"github.com/OffchainLabs/prysm/v6/api/server"
+	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
+	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/validator"
+	"github.com/OffchainLabs/prysm/v6/container/slice"
+	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	"github.com/OffchainLabs/prysm/v6/math"
+	enginev1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
+	ethv1 "github.com/OffchainLabs/prysm/v6/proto/eth/v1"
+	eth "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api/server"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/validator"
-	"github.com/prysmaticlabs/prysm/v5/container/slice"
-
-	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	"github.com/prysmaticlabs/prysm/v5/math"
-	enginev1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
 )
 
 var errNilValue = errors.New("nil value")
@@ -51,6 +52,9 @@ func HistoricalSummaryFromConsensus(s *eth.HistoricalSummary) *HistoricalSummary
 }
 
 func (s *SignedBLSToExecutionChange) ToConsensus() (*eth.SignedBLSToExecutionChange, error) {
+	if s.Message == nil {
+		return nil, server.NewDecodeError(errNilValue, "Message")
+	}
 	change, err := s.Message.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Message")
@@ -102,14 +106,17 @@ func SignedBLSChangeFromConsensus(ch *eth.SignedBLSToExecutionChange) *SignedBLS
 
 func SignedBLSChangesToConsensus(src []*SignedBLSToExecutionChange) ([]*eth.SignedBLSToExecutionChange, error) {
 	if src == nil {
-		return nil, errNilValue
+		return nil, server.NewDecodeError(errNilValue, "SignedBLSToExecutionChanges")
 	}
 	err := slice.VerifyMaxLength(src, 16)
 	if err != nil {
-		return nil, err
+		return nil, server.NewDecodeError(err, "SignedBLSToExecutionChanges")
 	}
 	changes := make([]*eth.SignedBLSToExecutionChange, len(src))
 	for i, ch := range src {
+		if ch == nil {
+			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d]", i))
+		}
 		changes[i], err = ch.ToConsensus()
 		if err != nil {
 			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d]", i))
@@ -155,6 +162,9 @@ func ForkFromConsensus(f *eth.Fork) *Fork {
 }
 
 func (s *SignedValidatorRegistration) ToConsensus() (*eth.SignedValidatorRegistrationV1, error) {
+	if s.Message == nil {
+		return nil, server.NewDecodeError(errNilValue, "Message")
+	}
 	msg, err := s.Message.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Message")
@@ -211,6 +221,9 @@ func SignedValidatorRegistrationFromConsensus(vr *eth.SignedValidatorRegistratio
 }
 
 func (s *SignedContributionAndProof) ToConsensus() (*eth.SignedContributionAndProof, error) {
+	if s.Message == nil {
+		return nil, server.NewDecodeError(errNilValue, "Message")
+	}
 	msg, err := s.Message.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Message")
@@ -235,6 +248,9 @@ func SignedContributionAndProofFromConsensus(c *eth.SignedContributionAndProof)
 }
 
 func (c *ContributionAndProof) ToConsensus() (*eth.ContributionAndProof, error) {
+	if c.Contribution == nil {
+		return nil, server.NewDecodeError(errNilValue, "Contribution")
+	}
 	contribution, err := c.Contribution.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Contribution")
@@ -243,7 +259,7 @@ func (c *ContributionAndProof) ToConsensus() (*eth.ContributionAndProof, error)
 	if err != nil {
 		return nil, server.NewDecodeError(err, "AggregatorIndex")
 	}
-	selectionProof, err := bytesutil.DecodeHexWithLength(c.SelectionProof, 96)
+	selectionProof, err := bytesutil.DecodeHexWithLength(c.SelectionProof, fieldparams.BLSSignatureLength)
 	if err != nil {
 		return nil, server.NewDecodeError(err, "SelectionProof")
 	}
@@ -306,6 +322,9 @@ func SyncCommitteeContributionFromConsensus(c *eth.SyncCommitteeContribution) *S
 }
 
 func (s *SignedAggregateAttestationAndProof) ToConsensus() (*eth.SignedAggregateAttestationAndProof, error) {
+	if s.Message == nil {
+		return nil, server.NewDecodeError(errNilValue, "Message")
+	}
 	msg, err := s.Message.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Message")
@@ -326,11 +345,14 @@ func (a *AggregateAttestationAndProof) ToConsensus() (*eth.AggregateAttestationA
 	if err != nil {
 		return nil, server.NewDecodeError(err, "AggregatorIndex")
 	}
+	if a.Aggregate == nil {
+		return nil, server.NewDecodeError(errNilValue, "Aggregate")
+	}
 	agg, err := a.Aggregate.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Aggregate")
 	}
-	proof, err := bytesutil.DecodeHexWithLength(a.SelectionProof, 96)
+	proof, err := bytesutil.DecodeHexWithLength(a.SelectionProof, fieldparams.BLSSignatureLength)
 	if err != nil {
 		return nil, server.NewDecodeError(err, "SelectionProof")
 	}
@@ -341,11 +363,56 @@ func (a *AggregateAttestationAndProof) ToConsensus() (*eth.AggregateAttestationA
 	}, nil
 }
 
+func (s *SignedAggregateAttestationAndProofElectra) ToConsensus() (*eth.SignedAggregateAttestationAndProofElectra, error) {
+	if s.Message == nil {
+		return nil, server.NewDecodeError(errNilValue, "Message")
+	}
+	msg, err := s.Message.ToConsensus()
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Message")
+	}
+	sig, err := bytesutil.DecodeHexWithLength(s.Signature, fieldparams.BLSSignatureLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Signature")
+	}
+
+	return &eth.SignedAggregateAttestationAndProofElectra{
+		Message:   msg,
+		Signature: sig,
+	}, nil
+}
+
+func (a *AggregateAttestationAndProofElectra) ToConsensus() (*eth.AggregateAttestationAndProofElectra, error) {
+	aggIndex, err := strconv.ParseUint(a.AggregatorIndex, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "AggregatorIndex")
+	}
+	if a.Aggregate == nil {
+		return nil, server.NewDecodeError(errNilValue, "Aggregate")
+	}
+	agg, err := a.Aggregate.ToConsensus()
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Aggregate")
+	}
+	proof, err := bytesutil.DecodeHexWithLength(a.SelectionProof, fieldparams.BLSSignatureLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "SelectionProof")
+	}
+	return &eth.AggregateAttestationAndProofElectra{
+		AggregatorIndex: primitives.ValidatorIndex(aggIndex),
+		Aggregate:       agg,
+		SelectionProof:  proof,
+	}, nil
+}
+
 func (a *Attestation) ToConsensus() (*eth.Attestation, error) {
 	aggBits, err := hexutil.Decode(a.AggregationBits)
 	if err != nil {
 		return nil, server.NewDecodeError(err, "AggregationBits")
 	}
+	if a.Data == nil {
+		return nil, server.NewDecodeError(errNilValue, "Data")
+	}
 	data, err := a.Data.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Data")
@@ -370,6 +437,82 @@ func AttFromConsensus(a *eth.Attestation) *Attestation {
 	}
 }
 
+func (a *AttestationElectra) ToConsensus() (*eth.AttestationElectra, error) {
+	aggBits, err := hexutil.Decode(a.AggregationBits)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "AggregationBits")
+	}
+	if a.Data == nil {
+		return nil, server.NewDecodeError(errNilValue, "Data")
+	}
+	data, err := a.Data.ToConsensus()
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Data")
+	}
+	sig, err := bytesutil.DecodeHexWithLength(a.Signature, fieldparams.BLSSignatureLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Signature")
+	}
+	committeeBits, err := hexutil.Decode(a.CommitteeBits)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "CommitteeBits")
+	}
+
+	return &eth.AttestationElectra{
+		AggregationBits: aggBits,
+		Data:            data,
+		Signature:       sig,
+		CommitteeBits:   committeeBits,
+	}, nil
+}
+
+func SingleAttFromConsensus(a *eth.SingleAttestation) *SingleAttestation {
+	return &SingleAttestation{
+		CommitteeIndex: fmt.Sprintf("%d", a.CommitteeId),
+		AttesterIndex:  fmt.Sprintf("%d", a.AttesterIndex),
+		Data:           AttDataFromConsensus(a.Data),
+		Signature:      hexutil.Encode(a.Signature),
+	}
+}
+
+func (a *SingleAttestation) ToConsensus() (*eth.SingleAttestation, error) {
+	ci, err := strconv.ParseUint(a.CommitteeIndex, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "CommitteeIndex")
+	}
+	ai, err := strconv.ParseUint(a.AttesterIndex, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "AttesterIndex")
+	}
+	if a.Data == nil {
+		return nil, server.NewDecodeError(errNilValue, "Data")
+	}
+	data, err := a.Data.ToConsensus()
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Data")
+	}
+	sig, err := bytesutil.DecodeHexWithLength(a.Signature, fieldparams.BLSSignatureLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Signature")
+	}
+
+	return &eth.SingleAttestation{
+		CommitteeId:   primitives.CommitteeIndex(ci),
+		AttesterIndex: primitives.ValidatorIndex(ai),
+		Data:          data,
+		Signature:     sig,
+	}, nil
+}
+
+func AttElectraFromConsensus(a *eth.AttestationElectra) *AttestationElectra {
+	return &AttestationElectra{
+		AggregationBits: hexutil.Encode(a.AggregationBits),
+		Data:            AttDataFromConsensus(a.Data),
+		Signature:       hexutil.Encode(a.Signature),
+		CommitteeBits:   hexutil.Encode(a.CommitteeBits),
+	}
+}
+
 func (a *AttestationData) ToConsensus() (*eth.AttestationData, error) {
 	slot, err := strconv.ParseUint(a.Slot, 10, 64)
 	if err != nil {
@@ -383,10 +526,16 @@ func (a *AttestationData) ToConsensus() (*eth.AttestationData, error) {
 	if err != nil {
 		return nil, server.NewDecodeError(err, "BeaconBlockRoot")
 	}
+	if a.Source == nil {
+		return nil, server.NewDecodeError(errNilValue, "Source")
+	}
 	source, err := a.Source.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Source")
 	}
+	if a.Target == nil {
+		return nil, server.NewDecodeError(errNilValue, "Target")
+	}
 	target, err := a.Target.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Target")
@@ -486,15 +635,17 @@ func (b *BeaconCommitteeSubscription) ToConsensus() (*validator.BeaconCommitteeS
 }
 
 func (e *SignedVoluntaryExit) ToConsensus() (*eth.SignedVoluntaryExit, error) {
-	sig, err := bytesutil.DecodeHexWithLength(e.Signature, fieldparams.BLSSignatureLength)
-	if err != nil {
-		return nil, server.NewDecodeError(err, "Signature")
+	if e.Message == nil {
+		return nil, server.NewDecodeError(errNilValue, "Message")
 	}
 	exit, err := e.Message.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Message")
 	}
-
+	sig, err := bytesutil.DecodeHexWithLength(e.Signature, fieldparams.BLSSignatureLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Signature")
+	}
 	return &eth.SignedVoluntaryExit{
 		Exit:      exit,
 		Signature: sig,
@@ -597,10 +748,16 @@ func Eth1DataFromConsensus(e1d *eth.Eth1Data) *Eth1Data {
 }
 
 func (s *ProposerSlashing) ToConsensus() (*eth.ProposerSlashing, error) {
+	if s.SignedHeader1 == nil {
+		return nil, server.NewDecodeError(errNilValue, "SignedHeader1")
+	}
 	h1, err := s.SignedHeader1.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "SignedHeader1")
 	}
+	if s.SignedHeader2 == nil {
+		return nil, server.NewDecodeError(errNilValue, "SignedHeader2")
+	}
 	h2, err := s.SignedHeader2.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "SignedHeader2")
@@ -613,10 +770,16 @@ func (s *ProposerSlashing) ToConsensus() (*eth.ProposerSlashing, error) {
 }
 
 func (s *AttesterSlashing) ToConsensus() (*eth.AttesterSlashing, error) {
+	if s.Attestation1 == nil {
+		return nil, server.NewDecodeError(errNilValue, "Attestation1")
+	}
 	att1, err := s.Attestation1.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Attestation1")
 	}
+	if s.Attestation2 == nil {
+		return nil, server.NewDecodeError(errNilValue, "Attestation2")
+	}
 	att2, err := s.Attestation2.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Attestation2")
@@ -624,7 +787,29 @@ func (s *AttesterSlashing) ToConsensus() (*eth.AttesterSlashing, error) {
 	return &eth.AttesterSlashing{Attestation_1: att1, Attestation_2: att2}, nil
 }
 
+func (s *AttesterSlashingElectra) ToConsensus() (*eth.AttesterSlashingElectra, error) {
+	if s.Attestation1 == nil {
+		return nil, server.NewDecodeError(errNilValue, "Attestation1")
+	}
+	att1, err := s.Attestation1.ToConsensus()
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Attestation1")
+	}
+	if s.Attestation2 == nil {
+		return nil, server.NewDecodeError(errNilValue, "Attestation2")
+	}
+	att2, err := s.Attestation2.ToConsensus()
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Attestation2")
+	}
+	return &eth.AttesterSlashingElectra{Attestation_1: att1, Attestation_2: att2}, nil
+}
+
 func (a *IndexedAttestation) ToConsensus() (*eth.IndexedAttestation, error) {
+	if err := slice.VerifyMaxLength(a.AttestingIndices, params.BeaconConfig().MaxValidatorsPerCommittee); err != nil {
+		return nil, err
+	}
+
 	indices := make([]uint64, len(a.AttestingIndices))
 	var err error
 	for i, ix := range a.AttestingIndices {
@@ -633,6 +818,9 @@ func (a *IndexedAttestation) ToConsensus() (*eth.IndexedAttestation, error) {
 			return nil, server.NewDecodeError(err, fmt.Sprintf("AttestingIndices[%d]", i))
 		}
 	}
+	if a.Data == nil {
+		return nil, server.NewDecodeError(errNilValue, "Data")
+	}
 	data, err := a.Data.ToConsensus()
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Data")
@@ -649,6 +837,41 @@ func (a *IndexedAttestation) ToConsensus() (*eth.IndexedAttestation, error) {
 	}, nil
 }
 
+func (a *IndexedAttestationElectra) ToConsensus() (*eth.IndexedAttestationElectra, error) {
+	if err := slice.VerifyMaxLength(
+		a.AttestingIndices,
+		params.BeaconConfig().MaxValidatorsPerCommittee*params.BeaconConfig().MaxCommitteesPerSlot,
+	); err != nil {
+		return nil, err
+	}
+
+	indices := make([]uint64, len(a.AttestingIndices))
+	var err error
+	for i, ix := range a.AttestingIndices {
+		indices[i], err = strconv.ParseUint(ix, 10, 64)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("AttestingIndices[%d]", i))
+		}
+	}
+	if a.Data == nil {
+		return nil, server.NewDecodeError(errNilValue, "Data")
+	}
+	data, err := a.Data.ToConsensus()
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Data")
+	}
+	sig, err := bytesutil.DecodeHexWithLength(a.Signature, fieldparams.BLSSignatureLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Signature")
+	}
+
+	return &eth.IndexedAttestationElectra{
+		AttestingIndices: indices,
+		Data:             data,
+		Signature:        sig,
+	}, nil
+}
+
 func WithdrawalsFromConsensus(ws []*enginev1.Withdrawal) []*Withdrawal {
 	result := make([]*Withdrawal, len(ws))
 	for i, w := range ws {
@@ -668,11 +891,11 @@ func WithdrawalFromConsensus(w *enginev1.Withdrawal) *Withdrawal {
 
 func ProposerSlashingsToConsensus(src []*ProposerSlashing) ([]*eth.ProposerSlashing, error) {
 	if src == nil {
-		return nil, errNilValue
+		return nil, server.NewDecodeError(errNilValue, "ProposerSlashings")
 	}
 	err := slice.VerifyMaxLength(src, 16)
 	if err != nil {
-		return nil, err
+		return nil, server.NewDecodeError(err, "ProposerSlashings")
 	}
 	proposerSlashings := make([]*eth.ProposerSlashing, len(src))
 	for i, s := range src {
@@ -801,11 +1024,11 @@ func ProposerSlashingFromConsensus(src *eth.ProposerSlashing) *ProposerSlashing
 
 func AttesterSlashingsToConsensus(src []*AttesterSlashing) ([]*eth.AttesterSlashing, error) {
 	if src == nil {
-		return nil, errNilValue
+		return nil, server.NewDecodeError(errNilValue, "AttesterSlashings")
 	}
 	err := slice.VerifyMaxLength(src, 2)
 	if err != nil {
-		return nil, err
+		return nil, server.NewDecodeError(err, "AttesterSlashings")
 	}
 
 	attesterSlashings := make([]*eth.AttesterSlashing, len(src))
@@ -816,10 +1039,19 @@ func AttesterSlashingsToConsensus(src []*AttesterSlashing) ([]*eth.AttesterSlash
 		if s.Attestation1 == nil {
 			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d].Attestation1", i))
 		}
+
+		if s.Attestation1.Data == nil {
+			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d].Attestation1.Data", i))
+		}
+
 		if s.Attestation2 == nil {
 			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d].Attestation2", i))
 		}
 
+		if s.Attestation2.Data == nil {
+			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d].Attestation2.Data", i))
+		}
+
 		a1Sig, err := bytesutil.DecodeHexWithLength(s.Attestation1.Signature, fieldparams.BLSSignatureLength)
 		if err != nil {
 			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d].Attestation1.Signature", i))
@@ -836,6 +1068,7 @@ func AttesterSlashingsToConsensus(src []*AttesterSlashing) ([]*eth.AttesterSlash
 			}
 			a1AttestingIndices[j] = attestingIndex
 		}
+
 		a1Data, err := s.Attestation1.Data.ToConsensus()
 		if err != nil {
 			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d].Attestation1.Data", i))
@@ -931,17 +1164,162 @@ func AttesterSlashingFromConsensus(src *eth.AttesterSlashing) *AttesterSlashing
 	}
 }
 
+func AttesterSlashingsElectraToConsensus(src []*AttesterSlashingElectra) ([]*eth.AttesterSlashingElectra, error) {
+	if src == nil {
+		return nil, server.NewDecodeError(errNilValue, "AttesterSlashingsElectra")
+	}
+	err := slice.VerifyMaxLength(src, fieldparams.MaxAttesterSlashingsElectra)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "AttesterSlashingsElectra")
+	}
+
+	attesterSlashings := make([]*eth.AttesterSlashingElectra, len(src))
+	for i, s := range src {
+		if s == nil {
+			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d]", i))
+		}
+
+		if s.Attestation1 == nil {
+			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d].Attestation1", i))
+		}
+
+		if s.Attestation1.Data == nil {
+			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d].Attestation1.Data", i))
+		}
+
+		if s.Attestation2 == nil {
+			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d].Attestation2", i))
+		}
+
+		if s.Attestation2.Data == nil {
+			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d].Attestation2.Data", i))
+		}
+
+		a1Sig, err := bytesutil.DecodeHexWithLength(s.Attestation1.Signature, fieldparams.BLSSignatureLength)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d].Attestation1.Signature", i))
+		}
+		err = slice.VerifyMaxLength(s.Attestation1.AttestingIndices, params.BeaconConfig().MaxValidatorsPerCommittee*params.BeaconConfig().MaxCommitteesPerSlot)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d].Attestation1.AttestingIndices", i))
+		}
+		a1AttestingIndices := make([]uint64, len(s.Attestation1.AttestingIndices))
+		for j, ix := range s.Attestation1.AttestingIndices {
+			attestingIndex, err := strconv.ParseUint(ix, 10, 64)
+			if err != nil {
+				return nil, server.NewDecodeError(err, fmt.Sprintf("[%d].Attestation1.AttestingIndices[%d]", i, j))
+			}
+			a1AttestingIndices[j] = attestingIndex
+		}
+		a1Data, err := s.Attestation1.Data.ToConsensus()
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d].Attestation1.Data", i))
+		}
+		a2Sig, err := bytesutil.DecodeHexWithLength(s.Attestation2.Signature, fieldparams.BLSSignatureLength)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d].Attestation2.Signature", i))
+		}
+		err = slice.VerifyMaxLength(s.Attestation2.AttestingIndices, params.BeaconConfig().MaxValidatorsPerCommittee*params.BeaconConfig().MaxCommitteesPerSlot)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d].Attestation2.AttestingIndices", i))
+		}
+		a2AttestingIndices := make([]uint64, len(s.Attestation2.AttestingIndices))
+		for j, ix := range s.Attestation2.AttestingIndices {
+			attestingIndex, err := strconv.ParseUint(ix, 10, 64)
+			if err != nil {
+				return nil, server.NewDecodeError(err, fmt.Sprintf("[%d].Attestation2.AttestingIndices[%d]", i, j))
+			}
+			a2AttestingIndices[j] = attestingIndex
+		}
+		a2Data, err := s.Attestation2.Data.ToConsensus()
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d].Attestation2.Data", i))
+		}
+		attesterSlashings[i] = &eth.AttesterSlashingElectra{
+			Attestation_1: &eth.IndexedAttestationElectra{
+				AttestingIndices: a1AttestingIndices,
+				Data:             a1Data,
+				Signature:        a1Sig,
+			},
+			Attestation_2: &eth.IndexedAttestationElectra{
+				AttestingIndices: a2AttestingIndices,
+				Data:             a2Data,
+				Signature:        a2Sig,
+			},
+		}
+	}
+	return attesterSlashings, nil
+}
+
+func AttesterSlashingsElectraFromConsensus(src []*eth.AttesterSlashingElectra) []*AttesterSlashingElectra {
+	attesterSlashings := make([]*AttesterSlashingElectra, len(src))
+	for i, s := range src {
+		attesterSlashings[i] = AttesterSlashingElectraFromConsensus(s)
+	}
+	return attesterSlashings
+}
+
+func AttesterSlashingElectraFromConsensus(src *eth.AttesterSlashingElectra) *AttesterSlashingElectra {
+	a1AttestingIndices := make([]string, len(src.Attestation_1.AttestingIndices))
+	for j, ix := range src.Attestation_1.AttestingIndices {
+		a1AttestingIndices[j] = fmt.Sprintf("%d", ix)
+	}
+	a2AttestingIndices := make([]string, len(src.Attestation_2.AttestingIndices))
+	for j, ix := range src.Attestation_2.AttestingIndices {
+		a2AttestingIndices[j] = fmt.Sprintf("%d", ix)
+	}
+	return &AttesterSlashingElectra{
+		Attestation1: &IndexedAttestationElectra{
+			AttestingIndices: a1AttestingIndices,
+			Data: &AttestationData{
+				Slot:            fmt.Sprintf("%d", src.Attestation_1.Data.Slot),
+				CommitteeIndex:  fmt.Sprintf("%d", src.Attestation_1.Data.CommitteeIndex),
+				BeaconBlockRoot: hexutil.Encode(src.Attestation_1.Data.BeaconBlockRoot),
+				Source: &Checkpoint{
+					Epoch: fmt.Sprintf("%d", src.Attestation_1.Data.Source.Epoch),
+					Root:  hexutil.Encode(src.Attestation_1.Data.Source.Root),
+				},
+				Target: &Checkpoint{
+					Epoch: fmt.Sprintf("%d", src.Attestation_1.Data.Target.Epoch),
+					Root:  hexutil.Encode(src.Attestation_1.Data.Target.Root),
+				},
+			},
+			Signature: hexutil.Encode(src.Attestation_1.Signature),
+		},
+		Attestation2: &IndexedAttestationElectra{
+			AttestingIndices: a2AttestingIndices,
+			Data: &AttestationData{
+				Slot:            fmt.Sprintf("%d", src.Attestation_2.Data.Slot),
+				CommitteeIndex:  fmt.Sprintf("%d", src.Attestation_2.Data.CommitteeIndex),
+				BeaconBlockRoot: hexutil.Encode(src.Attestation_2.Data.BeaconBlockRoot),
+				Source: &Checkpoint{
+					Epoch: fmt.Sprintf("%d", src.Attestation_2.Data.Source.Epoch),
+					Root:  hexutil.Encode(src.Attestation_2.Data.Source.Root),
+				},
+				Target: &Checkpoint{
+					Epoch: fmt.Sprintf("%d", src.Attestation_2.Data.Target.Epoch),
+					Root:  hexutil.Encode(src.Attestation_2.Data.Target.Root),
+				},
+			},
+			Signature: hexutil.Encode(src.Attestation_2.Signature),
+		},
+	}
+}
+
 func AttsToConsensus(src []*Attestation) ([]*eth.Attestation, error) {
 	if src == nil {
-		return nil, errNilValue
+		return nil, server.NewDecodeError(errNilValue, "Attestations")
 	}
 	err := slice.VerifyMaxLength(src, 128)
 	if err != nil {
-		return nil, err
+		return nil, server.NewDecodeError(err, "Attestations")
 	}
 
 	atts := make([]*eth.Attestation, len(src))
 	for i, a := range src {
+		if a == nil {
+			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d]", i))
+		}
 		atts[i], err = a.ToConsensus()
 		if err != nil {
 			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d]", i))
@@ -958,13 +1336,43 @@ func AttsFromConsensus(src []*eth.Attestation) []*Attestation {
 	return atts
 }
 
+func AttsElectraToConsensus(src []*AttestationElectra) ([]*eth.AttestationElectra, error) {
+	if src == nil {
+		return nil, server.NewDecodeError(errNilValue, "AttestationsElectra")
+	}
+	err := slice.VerifyMaxLength(src, 8)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "AttestationsElectra")
+	}
+
+	atts := make([]*eth.AttestationElectra, len(src))
+	for i, a := range src {
+		if a == nil {
+			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d]", i))
+		}
+		atts[i], err = a.ToConsensus()
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d]", i))
+		}
+	}
+	return atts, nil
+}
+
+func AttsElectraFromConsensus(src []*eth.AttestationElectra) []*AttestationElectra {
+	atts := make([]*AttestationElectra, len(src))
+	for i, a := range src {
+		atts[i] = AttElectraFromConsensus(a)
+	}
+	return atts
+}
+
 func DepositsToConsensus(src []*Deposit) ([]*eth.Deposit, error) {
 	if src == nil {
-		return nil, errNilValue
+		return nil, server.NewDecodeError(errNilValue, "Deposits")
 	}
 	err := slice.VerifyMaxLength(src, 16)
 	if err != nil {
-		return nil, err
+		return nil, server.NewDecodeError(err, "Deposits")
 	}
 
 	deposits := make([]*eth.Deposit, len(src))
@@ -1036,15 +1444,18 @@ func DepositsFromConsensus(src []*eth.Deposit) []*Deposit {
 
 func SignedExitsToConsensus(src []*SignedVoluntaryExit) ([]*eth.SignedVoluntaryExit, error) {
 	if src == nil {
-		return nil, errNilValue
+		return nil, server.NewDecodeError(errNilValue, "SignedVoluntaryExits")
 	}
 	err := slice.VerifyMaxLength(src, 16)
 	if err != nil {
-		return nil, err
+		return nil, server.NewDecodeError(err, "SignedVoluntaryExits")
 	}
 
 	exits := make([]*eth.SignedVoluntaryExit, len(src))
 	for i, e := range src {
+		if e == nil {
+			return nil, server.NewDecodeError(errNilValue, fmt.Sprintf("[%d]", i))
+		}
 		exits[i], err = e.ToConsensus()
 		if err != nil {
 			return nil, server.NewDecodeError(err, fmt.Sprintf("[%d]", i))
@@ -1088,3 +1499,81 @@ func DepositSnapshotFromConsensus(ds *eth.DepositSnapshot) *DepositSnapshot {
 		ExecutionBlockHeight: fmt.Sprintf("%d", ds.ExecutionDepth),
 	}
 }
+
+func PendingDepositsFromConsensus(ds []*eth.PendingDeposit) []*PendingDeposit {
+	deposits := make([]*PendingDeposit, len(ds))
+	for i, d := range ds {
+		deposits[i] = &PendingDeposit{
+			Pubkey:                hexutil.Encode(d.PublicKey),
+			WithdrawalCredentials: hexutil.Encode(d.WithdrawalCredentials),
+			Amount:                fmt.Sprintf("%d", d.Amount),
+			Signature:             hexutil.Encode(d.Signature),
+			Slot:                  fmt.Sprintf("%d", d.Slot),
+		}
+	}
+	return deposits
+}
+
+func PendingPartialWithdrawalsFromConsensus(ws []*eth.PendingPartialWithdrawal) []*PendingPartialWithdrawal {
+	withdrawals := make([]*PendingPartialWithdrawal, len(ws))
+	for i, w := range ws {
+		withdrawals[i] = &PendingPartialWithdrawal{
+			Index:             fmt.Sprintf("%d", w.Index),
+			Amount:            fmt.Sprintf("%d", w.Amount),
+			WithdrawableEpoch: fmt.Sprintf("%d", w.WithdrawableEpoch),
+		}
+	}
+	return withdrawals
+}
+
+func PendingConsolidationsFromConsensus(cs []*eth.PendingConsolidation) []*PendingConsolidation {
+	consolidations := make([]*PendingConsolidation, len(cs))
+	for i, c := range cs {
+		consolidations[i] = &PendingConsolidation{
+			SourceIndex: fmt.Sprintf("%d", c.SourceIndex),
+			TargetIndex: fmt.Sprintf("%d", c.TargetIndex),
+		}
+	}
+	return consolidations
+}
+
+func HeadEventFromV1(event *ethv1.EventHead) *HeadEvent {
+	return &HeadEvent{
+		Slot:                      fmt.Sprintf("%d", event.Slot),
+		Block:                     hexutil.Encode(event.Block),
+		State:                     hexutil.Encode(event.State),
+		EpochTransition:           event.EpochTransition,
+		ExecutionOptimistic:       event.ExecutionOptimistic,
+		PreviousDutyDependentRoot: hexutil.Encode(event.PreviousDutyDependentRoot),
+		CurrentDutyDependentRoot:  hexutil.Encode(event.CurrentDutyDependentRoot),
+	}
+}
+
+func FinalizedCheckpointEventFromV1(event *ethv1.EventFinalizedCheckpoint) *FinalizedCheckpointEvent {
+	return &FinalizedCheckpointEvent{
+		Block:               hexutil.Encode(event.Block),
+		State:               hexutil.Encode(event.State),
+		Epoch:               fmt.Sprintf("%d", event.Epoch),
+		ExecutionOptimistic: event.ExecutionOptimistic,
+	}
+}
+
+func EventChainReorgFromV1(event *ethv1.EventChainReorg) *ChainReorgEvent {
+	return &ChainReorgEvent{
+		Slot:                fmt.Sprintf("%d", event.Slot),
+		Depth:               fmt.Sprintf("%d", event.Depth),
+		OldHeadBlock:        hexutil.Encode(event.OldHeadBlock),
+		NewHeadBlock:        hexutil.Encode(event.NewHeadBlock),
+		OldHeadState:        hexutil.Encode(event.OldHeadState),
+		NewHeadState:        hexutil.Encode(event.NewHeadState),
+		Epoch:               fmt.Sprintf("%d", event.Epoch),
+		ExecutionOptimistic: event.ExecutionOptimistic,
+	}
+}
+
+func SyncAggregateFromConsensus(sa *eth.SyncAggregate) *SyncAggregate {
+	return &SyncAggregate{
+		SyncCommitteeBits:      hexutil.Encode(sa.SyncCommitteeBits),
+		SyncCommitteeSignature: hexutil.Encode(sa.SyncCommitteeSignature),
+	}
+}

api/server/structs/conversions_blob.go

@@ -0,0 +1,61 @@
+package structs
+
+import (
+	"strconv"
+
+	"github.com/OffchainLabs/prysm/v6/api/server"
+	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	eth "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+)
+
+func (sc *Sidecar) ToConsensus() (*eth.BlobSidecar, error) {
+	if sc == nil {
+		return nil, errNilValue
+	}
+
+	index, err := strconv.ParseUint(sc.Index, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Index")
+	}
+
+	blob, err := bytesutil.DecodeHexWithLength(sc.Blob, 131072)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Blob")
+	}
+
+	kzgCommitment, err := bytesutil.DecodeHexWithLength(sc.KzgCommitment, 48)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "KzgCommitment")
+	}
+
+	kzgProof, err := bytesutil.DecodeHexWithLength(sc.KzgProof, 48)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "KzgProof")
+	}
+
+	header, err := sc.SignedBeaconBlockHeader.ToConsensus()
+	if err != nil {
+		return nil, server.NewDecodeError(err, "SignedBeaconBlockHeader")
+	}
+
+	// decode the commitment inclusion proof
+	var commitmentInclusionProof [][]byte
+	for _, proof := range sc.CommitmentInclusionProof {
+		proofBytes, err := bytesutil.DecodeHexWithLength(proof, 32)
+		if err != nil {
+			return nil, server.NewDecodeError(err, "CommitmentInclusionProof")
+		}
+		commitmentInclusionProof = append(commitmentInclusionProof, proofBytes)
+	}
+
+	bsc := &eth.BlobSidecar{
+		Index:                    index,
+		Blob:                     blob,
+		KzgCommitment:            kzgCommitment,
+		KzgProof:                 kzgProof,
+		SignedBlockHeader:        header,
+		CommitmentInclusionProof: commitmentInclusionProof,
+	}
+
+	return bsc, nil
+}

api/server/structs/conversions_block_execution.go

@@ -0,0 +1,973 @@
+package structs
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/OffchainLabs/prysm/v6/api/server"
+	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
+	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/container/slice"
+	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	enginev1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+)
+
+// ----------------------------------------------------------------------------
+// Bellatrix
+// ----------------------------------------------------------------------------
+
+func ExecutionPayloadFromConsensus(payload *enginev1.ExecutionPayload) (*ExecutionPayload, error) {
+	baseFeePerGas, err := sszBytesToUint256String(payload.BaseFeePerGas)
+	if err != nil {
+		return nil, err
+	}
+	transactions := make([]string, len(payload.Transactions))
+	for i, tx := range payload.Transactions {
+		transactions[i] = hexutil.Encode(tx)
+	}
+
+	return &ExecutionPayload{
+		ParentHash:    hexutil.Encode(payload.ParentHash),
+		FeeRecipient:  hexutil.Encode(payload.FeeRecipient),
+		StateRoot:     hexutil.Encode(payload.StateRoot),
+		ReceiptsRoot:  hexutil.Encode(payload.ReceiptsRoot),
+		LogsBloom:     hexutil.Encode(payload.LogsBloom),
+		PrevRandao:    hexutil.Encode(payload.PrevRandao),
+		BlockNumber:   fmt.Sprintf("%d", payload.BlockNumber),
+		GasLimit:      fmt.Sprintf("%d", payload.GasLimit),
+		GasUsed:       fmt.Sprintf("%d", payload.GasUsed),
+		Timestamp:     fmt.Sprintf("%d", payload.Timestamp),
+		ExtraData:     hexutil.Encode(payload.ExtraData),
+		BaseFeePerGas: baseFeePerGas,
+		BlockHash:     hexutil.Encode(payload.BlockHash),
+		Transactions:  transactions,
+	}, nil
+}
+
+func (e *ExecutionPayload) ToConsensus() (*enginev1.ExecutionPayload, error) {
+	if e == nil {
+		return nil, server.NewDecodeError(errNilValue, "ExecutionPayload")
+	}
+	payloadParentHash, err := bytesutil.DecodeHexWithLength(e.ParentHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.ParentHash")
+	}
+	payloadFeeRecipient, err := bytesutil.DecodeHexWithLength(e.FeeRecipient, fieldparams.FeeRecipientLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.FeeRecipient")
+	}
+	payloadStateRoot, err := bytesutil.DecodeHexWithLength(e.StateRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.StateRoot")
+	}
+	payloadReceiptsRoot, err := bytesutil.DecodeHexWithLength(e.ReceiptsRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.ReceiptsRoot")
+	}
+	payloadLogsBloom, err := bytesutil.DecodeHexWithLength(e.LogsBloom, fieldparams.LogsBloomLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.LogsBloom")
+	}
+	payloadPrevRandao, err := bytesutil.DecodeHexWithLength(e.PrevRandao, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.PrevRandao")
+	}
+	payloadBlockNumber, err := strconv.ParseUint(e.BlockNumber, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.BlockNumber")
+	}
+	payloadGasLimit, err := strconv.ParseUint(e.GasLimit, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.GasLimit")
+	}
+	payloadGasUsed, err := strconv.ParseUint(e.GasUsed, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.GasUsed")
+	}
+	payloadTimestamp, err := strconv.ParseUint(e.Timestamp, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.Timestamp")
+	}
+	payloadExtraData, err := bytesutil.DecodeHexWithMaxLength(e.ExtraData, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.ExtraData")
+	}
+	payloadBaseFeePerGas, err := bytesutil.Uint256ToSSZBytes(e.BaseFeePerGas)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.BaseFeePerGas")
+	}
+	payloadBlockHash, err := bytesutil.DecodeHexWithLength(e.BlockHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.BlockHash")
+	}
+	err = slice.VerifyMaxLength(e.Transactions, fieldparams.MaxTxsPerPayloadLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.Transactions")
+	}
+	payloadTxs := make([][]byte, len(e.Transactions))
+	for i, tx := range e.Transactions {
+		payloadTxs[i], err = bytesutil.DecodeHexWithMaxLength(tx, fieldparams.MaxBytesPerTxLength)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionPayload.Transactions[%d]", i))
+		}
+	}
+	return &enginev1.ExecutionPayload{
+		ParentHash:    payloadParentHash,
+		FeeRecipient:  payloadFeeRecipient,
+		StateRoot:     payloadStateRoot,
+		ReceiptsRoot:  payloadReceiptsRoot,
+		LogsBloom:     payloadLogsBloom,
+		PrevRandao:    payloadPrevRandao,
+		BlockNumber:   payloadBlockNumber,
+		GasLimit:      payloadGasLimit,
+		GasUsed:       payloadGasUsed,
+		Timestamp:     payloadTimestamp,
+		ExtraData:     payloadExtraData,
+		BaseFeePerGas: payloadBaseFeePerGas,
+		BlockHash:     payloadBlockHash,
+		Transactions:  payloadTxs,
+	}, nil
+}
+
+func ExecutionPayloadHeaderFromConsensus(payload *enginev1.ExecutionPayloadHeader) (*ExecutionPayloadHeader, error) {
+	baseFeePerGas, err := sszBytesToUint256String(payload.BaseFeePerGas)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ExecutionPayloadHeader{
+		ParentHash:       hexutil.Encode(payload.ParentHash),
+		FeeRecipient:     hexutil.Encode(payload.FeeRecipient),
+		StateRoot:        hexutil.Encode(payload.StateRoot),
+		ReceiptsRoot:     hexutil.Encode(payload.ReceiptsRoot),
+		LogsBloom:        hexutil.Encode(payload.LogsBloom),
+		PrevRandao:       hexutil.Encode(payload.PrevRandao),
+		BlockNumber:      fmt.Sprintf("%d", payload.BlockNumber),
+		GasLimit:         fmt.Sprintf("%d", payload.GasLimit),
+		GasUsed:          fmt.Sprintf("%d", payload.GasUsed),
+		Timestamp:        fmt.Sprintf("%d", payload.Timestamp),
+		ExtraData:        hexutil.Encode(payload.ExtraData),
+		BaseFeePerGas:    baseFeePerGas,
+		BlockHash:        hexutil.Encode(payload.BlockHash),
+		TransactionsRoot: hexutil.Encode(payload.TransactionsRoot),
+	}, nil
+}
+
+func (e *ExecutionPayloadHeader) ToConsensus() (*enginev1.ExecutionPayloadHeader, error) {
+	if e == nil {
+		return nil, server.NewDecodeError(errNilValue, "ExecutionPayloadHeader")
+	}
+	payloadParentHash, err := bytesutil.DecodeHexWithLength(e.ParentHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.ParentHash")
+	}
+	payloadFeeRecipient, err := bytesutil.DecodeHexWithLength(e.FeeRecipient, fieldparams.FeeRecipientLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.FeeRecipient")
+	}
+	payloadStateRoot, err := bytesutil.DecodeHexWithLength(e.StateRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.StateRoot")
+	}
+	payloadReceiptsRoot, err := bytesutil.DecodeHexWithLength(e.ReceiptsRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.ReceiptsRoot")
+	}
+	payloadLogsBloom, err := bytesutil.DecodeHexWithLength(e.LogsBloom, fieldparams.LogsBloomLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.LogsBloom")
+	}
+	payloadPrevRandao, err := bytesutil.DecodeHexWithLength(e.PrevRandao, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.PrevRandao")
+	}
+	payloadBlockNumber, err := strconv.ParseUint(e.BlockNumber, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.BlockNumber")
+	}
+	payloadGasLimit, err := strconv.ParseUint(e.GasLimit, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.GasLimit")
+	}
+	payloadGasUsed, err := strconv.ParseUint(e.GasUsed, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.GasUsed")
+	}
+	payloadTimestamp, err := strconv.ParseUint(e.Timestamp, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.Timestamp")
+	}
+	payloadExtraData, err := bytesutil.DecodeHexWithMaxLength(e.ExtraData, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.ExtraData")
+	}
+	payloadBaseFeePerGas, err := bytesutil.Uint256ToSSZBytes(e.BaseFeePerGas)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.BaseFeePerGas")
+	}
+	payloadBlockHash, err := bytesutil.DecodeHexWithLength(e.BlockHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.BlockHash")
+	}
+	payloadTxsRoot, err := bytesutil.DecodeHexWithLength(e.TransactionsRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.TransactionsRoot")
+	}
+
+	return &enginev1.ExecutionPayloadHeader{
+		ParentHash:       payloadParentHash,
+		FeeRecipient:     payloadFeeRecipient,
+		StateRoot:        payloadStateRoot,
+		ReceiptsRoot:     payloadReceiptsRoot,
+		LogsBloom:        payloadLogsBloom,
+		PrevRandao:       payloadPrevRandao,
+		BlockNumber:      payloadBlockNumber,
+		GasLimit:         payloadGasLimit,
+		GasUsed:          payloadGasUsed,
+		Timestamp:        payloadTimestamp,
+		ExtraData:        payloadExtraData,
+		BaseFeePerGas:    payloadBaseFeePerGas,
+		BlockHash:        payloadBlockHash,
+		TransactionsRoot: payloadTxsRoot,
+	}, nil
+}
+
+// ----------------------------------------------------------------------------
+// Capella
+// ----------------------------------------------------------------------------
+
+func ExecutionPayloadCapellaFromConsensus(payload *enginev1.ExecutionPayloadCapella) (*ExecutionPayloadCapella, error) {
+	baseFeePerGas, err := sszBytesToUint256String(payload.BaseFeePerGas)
+	if err != nil {
+		return nil, err
+	}
+	transactions := make([]string, len(payload.Transactions))
+	for i, tx := range payload.Transactions {
+		transactions[i] = hexutil.Encode(tx)
+	}
+
+	return &ExecutionPayloadCapella{
+		ParentHash:    hexutil.Encode(payload.ParentHash),
+		FeeRecipient:  hexutil.Encode(payload.FeeRecipient),
+		StateRoot:     hexutil.Encode(payload.StateRoot),
+		ReceiptsRoot:  hexutil.Encode(payload.ReceiptsRoot),
+		LogsBloom:     hexutil.Encode(payload.LogsBloom),
+		PrevRandao:    hexutil.Encode(payload.PrevRandao),
+		BlockNumber:   fmt.Sprintf("%d", payload.BlockNumber),
+		GasLimit:      fmt.Sprintf("%d", payload.GasLimit),
+		GasUsed:       fmt.Sprintf("%d", payload.GasUsed),
+		Timestamp:     fmt.Sprintf("%d", payload.Timestamp),
+		ExtraData:     hexutil.Encode(payload.ExtraData),
+		BaseFeePerGas: baseFeePerGas,
+		BlockHash:     hexutil.Encode(payload.BlockHash),
+		Transactions:  transactions,
+		Withdrawals:   WithdrawalsFromConsensus(payload.Withdrawals),
+	}, nil
+}
+
+func (e *ExecutionPayloadCapella) ToConsensus() (*enginev1.ExecutionPayloadCapella, error) {
+	if e == nil {
+		return nil, server.NewDecodeError(errNilValue, "ExecutionPayload")
+	}
+	payloadParentHash, err := bytesutil.DecodeHexWithLength(e.ParentHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.ParentHash")
+	}
+	payloadFeeRecipient, err := bytesutil.DecodeHexWithLength(e.FeeRecipient, fieldparams.FeeRecipientLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.FeeRecipient")
+	}
+	payloadStateRoot, err := bytesutil.DecodeHexWithLength(e.StateRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.StateRoot")
+	}
+	payloadReceiptsRoot, err := bytesutil.DecodeHexWithLength(e.ReceiptsRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.ReceiptsRoot")
+	}
+	payloadLogsBloom, err := bytesutil.DecodeHexWithLength(e.LogsBloom, fieldparams.LogsBloomLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.LogsBloom")
+	}
+	payloadPrevRandao, err := bytesutil.DecodeHexWithLength(e.PrevRandao, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.PrevRandao")
+	}
+	payloadBlockNumber, err := strconv.ParseUint(e.BlockNumber, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.BlockNumber")
+	}
+	payloadGasLimit, err := strconv.ParseUint(e.GasLimit, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.GasLimit")
+	}
+	payloadGasUsed, err := strconv.ParseUint(e.GasUsed, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.GasUsed")
+	}
+	payloadTimestamp, err := strconv.ParseUint(e.Timestamp, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.Timestamp")
+	}
+	payloadExtraData, err := bytesutil.DecodeHexWithMaxLength(e.ExtraData, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.ExtraData")
+	}
+	payloadBaseFeePerGas, err := bytesutil.Uint256ToSSZBytes(e.BaseFeePerGas)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.BaseFeePerGas")
+	}
+	payloadBlockHash, err := bytesutil.DecodeHexWithLength(e.BlockHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.BlockHash")
+	}
+	err = slice.VerifyMaxLength(e.Transactions, fieldparams.MaxTxsPerPayloadLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.Transactions")
+	}
+	payloadTxs := make([][]byte, len(e.Transactions))
+	for i, tx := range e.Transactions {
+		payloadTxs[i], err = bytesutil.DecodeHexWithMaxLength(tx, fieldparams.MaxBytesPerTxLength)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionPayload.Transactions[%d]", i))
+		}
+	}
+	err = slice.VerifyMaxLength(e.Withdrawals, fieldparams.MaxWithdrawalsPerPayload)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.Withdrawals")
+	}
+	withdrawals := make([]*enginev1.Withdrawal, len(e.Withdrawals))
+	for i, w := range e.Withdrawals {
+		withdrawalIndex, err := strconv.ParseUint(w.WithdrawalIndex, 10, 64)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionPayload.Withdrawals[%d].WithdrawalIndex", i))
+		}
+		validatorIndex, err := strconv.ParseUint(w.ValidatorIndex, 10, 64)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionPayload.Withdrawals[%d].ValidatorIndex", i))
+		}
+		address, err := bytesutil.DecodeHexWithLength(w.ExecutionAddress, common.AddressLength)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionPayload.Withdrawals[%d].ExecutionAddress", i))
+		}
+		amount, err := strconv.ParseUint(w.Amount, 10, 64)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionPayload.Withdrawals[%d].Amount", i))
+		}
+		withdrawals[i] = &enginev1.Withdrawal{
+			Index:          withdrawalIndex,
+			ValidatorIndex: primitives.ValidatorIndex(validatorIndex),
+			Address:        address,
+			Amount:         amount,
+		}
+	}
+	return &enginev1.ExecutionPayloadCapella{
+		ParentHash:    payloadParentHash,
+		FeeRecipient:  payloadFeeRecipient,
+		StateRoot:     payloadStateRoot,
+		ReceiptsRoot:  payloadReceiptsRoot,
+		LogsBloom:     payloadLogsBloom,
+		PrevRandao:    payloadPrevRandao,
+		BlockNumber:   payloadBlockNumber,
+		GasLimit:      payloadGasLimit,
+		GasUsed:       payloadGasUsed,
+		Timestamp:     payloadTimestamp,
+		ExtraData:     payloadExtraData,
+		BaseFeePerGas: payloadBaseFeePerGas,
+		BlockHash:     payloadBlockHash,
+		Transactions:  payloadTxs,
+		Withdrawals:   withdrawals,
+	}, nil
+}
+
+func ExecutionPayloadHeaderCapellaFromConsensus(payload *enginev1.ExecutionPayloadHeaderCapella) (*ExecutionPayloadHeaderCapella, error) {
+	baseFeePerGas, err := sszBytesToUint256String(payload.BaseFeePerGas)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ExecutionPayloadHeaderCapella{
+		ParentHash:       hexutil.Encode(payload.ParentHash),
+		FeeRecipient:     hexutil.Encode(payload.FeeRecipient),
+		StateRoot:        hexutil.Encode(payload.StateRoot),
+		ReceiptsRoot:     hexutil.Encode(payload.ReceiptsRoot),
+		LogsBloom:        hexutil.Encode(payload.LogsBloom),
+		PrevRandao:       hexutil.Encode(payload.PrevRandao),
+		BlockNumber:      fmt.Sprintf("%d", payload.BlockNumber),
+		GasLimit:         fmt.Sprintf("%d", payload.GasLimit),
+		GasUsed:          fmt.Sprintf("%d", payload.GasUsed),
+		Timestamp:        fmt.Sprintf("%d", payload.Timestamp),
+		ExtraData:        hexutil.Encode(payload.ExtraData),
+		BaseFeePerGas:    baseFeePerGas,
+		BlockHash:        hexutil.Encode(payload.BlockHash),
+		TransactionsRoot: hexutil.Encode(payload.TransactionsRoot),
+		WithdrawalsRoot:  hexutil.Encode(payload.WithdrawalsRoot),
+	}, nil
+}
+
+func (e *ExecutionPayloadHeaderCapella) ToConsensus() (*enginev1.ExecutionPayloadHeaderCapella, error) {
+	if e == nil {
+		return nil, server.NewDecodeError(errNilValue, "ExecutionPayloadHeader")
+	}
+	payloadParentHash, err := bytesutil.DecodeHexWithLength(e.ParentHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.ParentHash")
+	}
+	payloadFeeRecipient, err := bytesutil.DecodeHexWithLength(e.FeeRecipient, fieldparams.FeeRecipientLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.FeeRecipient")
+	}
+	payloadStateRoot, err := bytesutil.DecodeHexWithLength(e.StateRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.StateRoot")
+	}
+	payloadReceiptsRoot, err := bytesutil.DecodeHexWithLength(e.ReceiptsRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.ReceiptsRoot")
+	}
+	payloadLogsBloom, err := bytesutil.DecodeHexWithLength(e.LogsBloom, fieldparams.LogsBloomLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.LogsBloom")
+	}
+	payloadPrevRandao, err := bytesutil.DecodeHexWithLength(e.PrevRandao, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.PrevRandao")
+	}
+	payloadBlockNumber, err := strconv.ParseUint(e.BlockNumber, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.BlockNumber")
+	}
+	payloadGasLimit, err := strconv.ParseUint(e.GasLimit, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.GasLimit")
+	}
+	payloadGasUsed, err := strconv.ParseUint(e.GasUsed, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.GasUsed")
+	}
+	payloadTimestamp, err := strconv.ParseUint(e.Timestamp, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.Timestamp")
+	}
+	payloadExtraData, err := bytesutil.DecodeHexWithMaxLength(e.ExtraData, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.ExtraData")
+	}
+	payloadBaseFeePerGas, err := bytesutil.Uint256ToSSZBytes(e.BaseFeePerGas)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.BaseFeePerGas")
+	}
+	payloadBlockHash, err := bytesutil.DecodeHexWithMaxLength(e.BlockHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.BlockHash")
+	}
+	payloadTxsRoot, err := bytesutil.DecodeHexWithMaxLength(e.TransactionsRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.TransactionsRoot")
+	}
+	payloadWithdrawalsRoot, err := bytesutil.DecodeHexWithMaxLength(e.WithdrawalsRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.WithdrawalsRoot")
+	}
+	return &enginev1.ExecutionPayloadHeaderCapella{
+		ParentHash:       payloadParentHash,
+		FeeRecipient:     payloadFeeRecipient,
+		StateRoot:        payloadStateRoot,
+		ReceiptsRoot:     payloadReceiptsRoot,
+		LogsBloom:        payloadLogsBloom,
+		PrevRandao:       payloadPrevRandao,
+		BlockNumber:      payloadBlockNumber,
+		GasLimit:         payloadGasLimit,
+		GasUsed:          payloadGasUsed,
+		Timestamp:        payloadTimestamp,
+		ExtraData:        payloadExtraData,
+		BaseFeePerGas:    payloadBaseFeePerGas,
+		BlockHash:        payloadBlockHash,
+		TransactionsRoot: payloadTxsRoot,
+		WithdrawalsRoot:  payloadWithdrawalsRoot,
+	}, nil
+}
+
+// ----------------------------------------------------------------------------
+// Deneb
+// ----------------------------------------------------------------------------
+
+func ExecutionPayloadDenebFromConsensus(payload *enginev1.ExecutionPayloadDeneb) (*ExecutionPayloadDeneb, error) {
+	baseFeePerGas, err := sszBytesToUint256String(payload.BaseFeePerGas)
+	if err != nil {
+		return nil, err
+	}
+	transactions := make([]string, len(payload.Transactions))
+	for i, tx := range payload.Transactions {
+		transactions[i] = hexutil.Encode(tx)
+	}
+
+	return &ExecutionPayloadDeneb{
+		ParentHash:    hexutil.Encode(payload.ParentHash),
+		FeeRecipient:  hexutil.Encode(payload.FeeRecipient),
+		StateRoot:     hexutil.Encode(payload.StateRoot),
+		ReceiptsRoot:  hexutil.Encode(payload.ReceiptsRoot),
+		LogsBloom:     hexutil.Encode(payload.LogsBloom),
+		PrevRandao:    hexutil.Encode(payload.PrevRandao),
+		BlockNumber:   fmt.Sprintf("%d", payload.BlockNumber),
+		GasLimit:      fmt.Sprintf("%d", payload.GasLimit),
+		GasUsed:       fmt.Sprintf("%d", payload.GasUsed),
+		Timestamp:     fmt.Sprintf("%d", payload.Timestamp),
+		ExtraData:     hexutil.Encode(payload.ExtraData),
+		BaseFeePerGas: baseFeePerGas,
+		BlockHash:     hexutil.Encode(payload.BlockHash),
+		Transactions:  transactions,
+		Withdrawals:   WithdrawalsFromConsensus(payload.Withdrawals),
+		BlobGasUsed:   fmt.Sprintf("%d", payload.BlobGasUsed),
+		ExcessBlobGas: fmt.Sprintf("%d", payload.ExcessBlobGas),
+	}, nil
+}
+
+func (e *ExecutionPayloadDeneb) ToConsensus() (*enginev1.ExecutionPayloadDeneb, error) {
+	if e == nil {
+		return nil, server.NewDecodeError(errNilValue, "ExecutionPayload")
+	}
+	payloadParentHash, err := bytesutil.DecodeHexWithLength(e.ParentHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.ParentHash")
+	}
+	payloadFeeRecipient, err := bytesutil.DecodeHexWithLength(e.FeeRecipient, fieldparams.FeeRecipientLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.FeeRecipient")
+	}
+	payloadStateRoot, err := bytesutil.DecodeHexWithLength(e.StateRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.StateRoot")
+	}
+	payloadReceiptsRoot, err := bytesutil.DecodeHexWithLength(e.ReceiptsRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.ReceiptsRoot")
+	}
+	payloadLogsBloom, err := bytesutil.DecodeHexWithLength(e.LogsBloom, fieldparams.LogsBloomLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.LogsBloom")
+	}
+	payloadPrevRandao, err := bytesutil.DecodeHexWithLength(e.PrevRandao, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.PrevRandao")
+	}
+	payloadBlockNumber, err := strconv.ParseUint(e.BlockNumber, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.BlockNumber")
+	}
+	payloadGasLimit, err := strconv.ParseUint(e.GasLimit, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.GasLimit")
+	}
+	payloadGasUsed, err := strconv.ParseUint(e.GasUsed, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.GasUsed")
+	}
+	payloadTimestamp, err := strconv.ParseUint(e.Timestamp, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.Timestamp")
+	}
+	payloadExtraData, err := bytesutil.DecodeHexWithMaxLength(e.ExtraData, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.ExtraData")
+	}
+	payloadBaseFeePerGas, err := bytesutil.Uint256ToSSZBytes(e.BaseFeePerGas)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.BaseFeePerGas")
+	}
+	payloadBlockHash, err := bytesutil.DecodeHexWithLength(e.BlockHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.BlockHash")
+	}
+	err = slice.VerifyMaxLength(e.Transactions, fieldparams.MaxTxsPerPayloadLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.Transactions")
+	}
+	txs := make([][]byte, len(e.Transactions))
+	for i, tx := range e.Transactions {
+		txs[i], err = bytesutil.DecodeHexWithMaxLength(tx, fieldparams.MaxBytesPerTxLength)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionPayload.Transactions[%d]", i))
+		}
+	}
+	err = slice.VerifyMaxLength(e.Withdrawals, fieldparams.MaxWithdrawalsPerPayload)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.Withdrawals")
+	}
+	withdrawals := make([]*enginev1.Withdrawal, len(e.Withdrawals))
+	for i, w := range e.Withdrawals {
+		withdrawalIndex, err := strconv.ParseUint(w.WithdrawalIndex, 10, 64)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionPayload.Withdrawals[%d].WithdrawalIndex", i))
+		}
+		validatorIndex, err := strconv.ParseUint(w.ValidatorIndex, 10, 64)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionPayload.Withdrawals[%d].ValidatorIndex", i))
+		}
+		address, err := bytesutil.DecodeHexWithLength(w.ExecutionAddress, common.AddressLength)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionPayload.Withdrawals[%d].ExecutionAddress", i))
+		}
+		amount, err := strconv.ParseUint(w.Amount, 10, 64)
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionPayload.Withdrawals[%d].Amount", i))
+		}
+		withdrawals[i] = &enginev1.Withdrawal{
+			Index:          withdrawalIndex,
+			ValidatorIndex: primitives.ValidatorIndex(validatorIndex),
+			Address:        address,
+			Amount:         amount,
+		}
+	}
+
+	payloadBlobGasUsed, err := strconv.ParseUint(e.BlobGasUsed, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.BlobGasUsed")
+	}
+	payloadExcessBlobGas, err := strconv.ParseUint(e.ExcessBlobGas, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.ExcessBlobGas")
+	}
+	return &enginev1.ExecutionPayloadDeneb{
+		ParentHash:    payloadParentHash,
+		FeeRecipient:  payloadFeeRecipient,
+		StateRoot:     payloadStateRoot,
+		ReceiptsRoot:  payloadReceiptsRoot,
+		LogsBloom:     payloadLogsBloom,
+		PrevRandao:    payloadPrevRandao,
+		BlockNumber:   payloadBlockNumber,
+		GasLimit:      payloadGasLimit,
+		GasUsed:       payloadGasUsed,
+		Timestamp:     payloadTimestamp,
+		ExtraData:     payloadExtraData,
+		BaseFeePerGas: payloadBaseFeePerGas,
+		BlockHash:     payloadBlockHash,
+		Transactions:  txs,
+		Withdrawals:   withdrawals,
+		BlobGasUsed:   payloadBlobGasUsed,
+		ExcessBlobGas: payloadExcessBlobGas,
+	}, nil
+}
+
+func ExecutionPayloadHeaderDenebFromConsensus(payload *enginev1.ExecutionPayloadHeaderDeneb) (*ExecutionPayloadHeaderDeneb, error) {
+	baseFeePerGas, err := sszBytesToUint256String(payload.BaseFeePerGas)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ExecutionPayloadHeaderDeneb{
+		ParentHash:       hexutil.Encode(payload.ParentHash),
+		FeeRecipient:     hexutil.Encode(payload.FeeRecipient),
+		StateRoot:        hexutil.Encode(payload.StateRoot),
+		ReceiptsRoot:     hexutil.Encode(payload.ReceiptsRoot),
+		LogsBloom:        hexutil.Encode(payload.LogsBloom),
+		PrevRandao:       hexutil.Encode(payload.PrevRandao),
+		BlockNumber:      fmt.Sprintf("%d", payload.BlockNumber),
+		GasLimit:         fmt.Sprintf("%d", payload.GasLimit),
+		GasUsed:          fmt.Sprintf("%d", payload.GasUsed),
+		Timestamp:        fmt.Sprintf("%d", payload.Timestamp),
+		ExtraData:        hexutil.Encode(payload.ExtraData),
+		BaseFeePerGas:    baseFeePerGas,
+		BlockHash:        hexutil.Encode(payload.BlockHash),
+		TransactionsRoot: hexutil.Encode(payload.TransactionsRoot),
+		WithdrawalsRoot:  hexutil.Encode(payload.WithdrawalsRoot),
+		BlobGasUsed:      fmt.Sprintf("%d", payload.BlobGasUsed),
+		ExcessBlobGas:    fmt.Sprintf("%d", payload.ExcessBlobGas),
+	}, nil
+}
+
+func (e *ExecutionPayloadHeaderDeneb) ToConsensus() (*enginev1.ExecutionPayloadHeaderDeneb, error) {
+	if e == nil {
+		return nil, server.NewDecodeError(errNilValue, "ExecutionPayloadHeader")
+	}
+	payloadParentHash, err := bytesutil.DecodeHexWithLength(e.ParentHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.ParentHash")
+	}
+	payloadFeeRecipient, err := bytesutil.DecodeHexWithLength(e.FeeRecipient, fieldparams.FeeRecipientLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.FeeRecipient")
+	}
+	payloadStateRoot, err := bytesutil.DecodeHexWithLength(e.StateRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.StateRoot")
+	}
+	payloadReceiptsRoot, err := bytesutil.DecodeHexWithLength(e.ReceiptsRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.ReceiptsRoot")
+	}
+	payloadLogsBloom, err := bytesutil.DecodeHexWithLength(e.LogsBloom, fieldparams.LogsBloomLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.LogsBloom")
+	}
+	payloadPrevRandao, err := bytesutil.DecodeHexWithLength(e.PrevRandao, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.PrevRandao")
+	}
+	payloadBlockNumber, err := strconv.ParseUint(e.BlockNumber, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.BlockNumber")
+	}
+	payloadGasLimit, err := strconv.ParseUint(e.GasLimit, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.GasLimit")
+	}
+	payloadGasUsed, err := strconv.ParseUint(e.GasUsed, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.GasUsed")
+	}
+	payloadTimestamp, err := strconv.ParseUint(e.Timestamp, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.Timestamp")
+	}
+	payloadExtraData, err := bytesutil.DecodeHexWithMaxLength(e.ExtraData, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.ExtraData")
+	}
+	payloadBaseFeePerGas, err := bytesutil.Uint256ToSSZBytes(e.BaseFeePerGas)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.BaseFeePerGas")
+	}
+	payloadBlockHash, err := bytesutil.DecodeHexWithLength(e.BlockHash, common.HashLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.BlockHash")
+	}
+	payloadTxsRoot, err := bytesutil.DecodeHexWithLength(e.TransactionsRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.TransactionsRoot")
+	}
+	payloadWithdrawalsRoot, err := bytesutil.DecodeHexWithLength(e.WithdrawalsRoot, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayloadHeader.WithdrawalsRoot")
+	}
+	payloadBlobGasUsed, err := strconv.ParseUint(e.BlobGasUsed, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.BlobGasUsed")
+	}
+	payloadExcessBlobGas, err := strconv.ParseUint(e.ExcessBlobGas, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ExecutionPayload.ExcessBlobGas")
+	}
+	return &enginev1.ExecutionPayloadHeaderDeneb{
+		ParentHash:       payloadParentHash,
+		FeeRecipient:     payloadFeeRecipient,
+		StateRoot:        payloadStateRoot,
+		ReceiptsRoot:     payloadReceiptsRoot,
+		LogsBloom:        payloadLogsBloom,
+		PrevRandao:       payloadPrevRandao,
+		BlockNumber:      payloadBlockNumber,
+		GasLimit:         payloadGasLimit,
+		GasUsed:          payloadGasUsed,
+		Timestamp:        payloadTimestamp,
+		ExtraData:        payloadExtraData,
+		BaseFeePerGas:    payloadBaseFeePerGas,
+		BlockHash:        payloadBlockHash,
+		TransactionsRoot: payloadTxsRoot,
+		WithdrawalsRoot:  payloadWithdrawalsRoot,
+		BlobGasUsed:      payloadBlobGasUsed,
+		ExcessBlobGas:    payloadExcessBlobGas,
+	}, nil
+}
+
+// ----------------------------------------------------------------------------
+// Electra
+// ----------------------------------------------------------------------------
+
+var (
+	ExecutionPayloadElectraFromConsensus       = ExecutionPayloadDenebFromConsensus
+	ExecutionPayloadHeaderElectraFromConsensus = ExecutionPayloadHeaderDenebFromConsensus
+)
+
+func WithdrawalRequestsFromConsensus(ws []*enginev1.WithdrawalRequest) []*WithdrawalRequest {
+	result := make([]*WithdrawalRequest, len(ws))
+	for i, w := range ws {
+		result[i] = WithdrawalRequestFromConsensus(w)
+	}
+	return result
+}
+
+func WithdrawalRequestFromConsensus(w *enginev1.WithdrawalRequest) *WithdrawalRequest {
+	return &WithdrawalRequest{
+		SourceAddress:   hexutil.Encode(w.SourceAddress),
+		ValidatorPubkey: hexutil.Encode(w.ValidatorPubkey),
+		Amount:          fmt.Sprintf("%d", w.Amount),
+	}
+}
+
+func (w *WithdrawalRequest) ToConsensus() (*enginev1.WithdrawalRequest, error) {
+	if w == nil {
+		return nil, server.NewDecodeError(errNilValue, "WithdrawalRequest")
+	}
+	src, err := bytesutil.DecodeHexWithLength(w.SourceAddress, common.AddressLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "SourceAddress")
+	}
+	pubkey, err := bytesutil.DecodeHexWithLength(w.ValidatorPubkey, fieldparams.BLSPubkeyLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "ValidatorPubkey")
+	}
+	amount, err := strconv.ParseUint(w.Amount, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Amount")
+	}
+	return &enginev1.WithdrawalRequest{
+		SourceAddress:   src,
+		ValidatorPubkey: pubkey,
+		Amount:          amount,
+	}, nil
+}
+
+func ConsolidationRequestsFromConsensus(cs []*enginev1.ConsolidationRequest) []*ConsolidationRequest {
+	result := make([]*ConsolidationRequest, len(cs))
+	for i, c := range cs {
+		result[i] = ConsolidationRequestFromConsensus(c)
+	}
+	return result
+}
+
+func ConsolidationRequestFromConsensus(c *enginev1.ConsolidationRequest) *ConsolidationRequest {
+	return &ConsolidationRequest{
+		SourceAddress: hexutil.Encode(c.SourceAddress),
+		SourcePubkey:  hexutil.Encode(c.SourcePubkey),
+		TargetPubkey:  hexutil.Encode(c.TargetPubkey),
+	}
+}
+
+func (c *ConsolidationRequest) ToConsensus() (*enginev1.ConsolidationRequest, error) {
+	if c == nil {
+		return nil, server.NewDecodeError(errNilValue, "ConsolidationRequest")
+	}
+	srcAddress, err := bytesutil.DecodeHexWithLength(c.SourceAddress, common.AddressLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "SourceAddress")
+	}
+	srcPubkey, err := bytesutil.DecodeHexWithLength(c.SourcePubkey, fieldparams.BLSPubkeyLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "SourcePubkey")
+	}
+	targetPubkey, err := bytesutil.DecodeHexWithLength(c.TargetPubkey, fieldparams.BLSPubkeyLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "TargetPubkey")
+	}
+	return &enginev1.ConsolidationRequest{
+		SourceAddress: srcAddress,
+		SourcePubkey:  srcPubkey,
+		TargetPubkey:  targetPubkey,
+	}, nil
+}
+
+func DepositRequestsFromConsensus(ds []*enginev1.DepositRequest) []*DepositRequest {
+	result := make([]*DepositRequest, len(ds))
+	for i, d := range ds {
+		result[i] = DepositRequestFromConsensus(d)
+	}
+	return result
+}
+
+func DepositRequestFromConsensus(d *enginev1.DepositRequest) *DepositRequest {
+	return &DepositRequest{
+		Pubkey:                hexutil.Encode(d.Pubkey),
+		WithdrawalCredentials: hexutil.Encode(d.WithdrawalCredentials),
+		Amount:                fmt.Sprintf("%d", d.Amount),
+		Signature:             hexutil.Encode(d.Signature),
+		Index:                 fmt.Sprintf("%d", d.Index),
+	}
+}
+
+func (d *DepositRequest) ToConsensus() (*enginev1.DepositRequest, error) {
+	if d == nil {
+		return nil, server.NewDecodeError(errNilValue, "DepositRequest")
+	}
+	pubkey, err := bytesutil.DecodeHexWithLength(d.Pubkey, fieldparams.BLSPubkeyLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Pubkey")
+	}
+	withdrawalCredentials, err := bytesutil.DecodeHexWithLength(d.WithdrawalCredentials, fieldparams.RootLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "WithdrawalCredentials")
+	}
+	amount, err := strconv.ParseUint(d.Amount, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Amount")
+	}
+	sig, err := bytesutil.DecodeHexWithLength(d.Signature, fieldparams.BLSSignatureLength)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Signature")
+	}
+	index, err := strconv.ParseUint(d.Index, 10, 64)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Index")
+	}
+	return &enginev1.DepositRequest{
+		Pubkey:                pubkey,
+		WithdrawalCredentials: withdrawalCredentials,
+		Amount:                amount,
+		Signature:             sig,
+		Index:                 index,
+	}, nil
+}
+
+func ExecutionRequestsFromConsensus(er *enginev1.ExecutionRequests) *ExecutionRequests {
+	return &ExecutionRequests{
+		Deposits:       DepositRequestsFromConsensus(er.Deposits),
+		Withdrawals:    WithdrawalRequestsFromConsensus(er.Withdrawals),
+		Consolidations: ConsolidationRequestsFromConsensus(er.Consolidations),
+	}
+}
+
+func (e *ExecutionRequests) ToConsensus() (*enginev1.ExecutionRequests, error) {
+	if e == nil {
+		return nil, server.NewDecodeError(errNilValue, "ExecutionRequests")
+	}
+	var err error
+	if err = slice.VerifyMaxLength(e.Deposits, params.BeaconConfig().MaxDepositRequestsPerPayload); err != nil {
+		return nil, err
+	}
+	depositRequests := make([]*enginev1.DepositRequest, len(e.Deposits))
+	for i, d := range e.Deposits {
+		depositRequests[i], err = d.ToConsensus()
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionRequests.Deposits[%d]", i))
+		}
+	}
+
+	if err = slice.VerifyMaxLength(e.Withdrawals, params.BeaconConfig().MaxWithdrawalRequestsPerPayload); err != nil {
+		return nil, err
+	}
+	withdrawalRequests := make([]*enginev1.WithdrawalRequest, len(e.Withdrawals))
+	for i, w := range e.Withdrawals {
+		withdrawalRequests[i], err = w.ToConsensus()
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionRequests.Withdrawals[%d]", i))
+		}
+	}
+
+	if err = slice.VerifyMaxLength(e.Consolidations, params.BeaconConfig().MaxConsolidationsRequestsPerPayload); err != nil {
+		return nil, err
+	}
+	consolidationRequests := make([]*enginev1.ConsolidationRequest, len(e.Consolidations))
+	for i, c := range e.Consolidations {
+		consolidationRequests[i], err = c.ToConsensus()
+		if err != nil {
+			return nil, server.NewDecodeError(err, fmt.Sprintf("ExecutionRequests.Consolidations[%d]", i))
+		}
+	}
+	return &enginev1.ExecutionRequests{
+		Deposits:       depositRequests,
+		Withdrawals:    withdrawalRequests,
+		Consolidations: consolidationRequests,
+	}, nil
+}
+
+// ----------------------------------------------------------------------------
+// Fulu
+// ----------------------------------------------------------------------------
+
+var (
+	ExecutionPayloadFuluFromConsensus       = ExecutionPayloadDenebFromConsensus
+	ExecutionPayloadHeaderFuluFromConsensus = ExecutionPayloadHeaderDenebFromConsensus
+	BeaconBlockFuluFromConsensus            = BeaconBlockElectraFromConsensus
+)

api/server/structs/conversions_block_execution_test.go

@@ -0,0 +1,563 @@
+package structs
+
+import (
+	"fmt"
+	"testing"
+
+	enginev1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+)
+
+func fillByteSlice(sliceLength int, value byte) []byte {
+	bytes := make([]byte, sliceLength)
+
+	for index := range bytes {
+		bytes[index] = value
+	}
+
+	return bytes
+}
+
+// TestExecutionPayloadFromConsensus_HappyPath checks the
+// ExecutionPayloadFromConsensus function under normal conditions.
+func TestExecutionPayloadFromConsensus_HappyPath(t *testing.T) {
+	consensusPayload := &enginev1.ExecutionPayload{
+		ParentHash:    fillByteSlice(common.HashLength, 0xaa),
+		FeeRecipient:  fillByteSlice(20, 0xbb),
+		StateRoot:     fillByteSlice(32, 0xcc),
+		ReceiptsRoot:  fillByteSlice(32, 0xdd),
+		LogsBloom:     fillByteSlice(256, 0xee),
+		PrevRandao:    fillByteSlice(32, 0xff),
+		BlockNumber:   12345,
+		GasLimit:      15000000,
+		GasUsed:       8000000,
+		Timestamp:     1680000000,
+		ExtraData:     fillByteSlice(8, 0x11),
+		BaseFeePerGas: fillByteSlice(32, 0x01),
+		BlockHash:     fillByteSlice(common.HashLength, 0x22),
+		Transactions: [][]byte{
+			fillByteSlice(10, 0x33),
+			fillByteSlice(10, 0x44),
+		},
+	}
+
+	result, err := ExecutionPayloadFromConsensus(consensusPayload)
+	require.NoError(t, err)
+	require.NotNil(t, result)
+	require.Equal(t, hexutil.Encode(consensusPayload.ParentHash), result.ParentHash)
+	require.Equal(t, hexutil.Encode(consensusPayload.FeeRecipient), result.FeeRecipient)
+	require.Equal(t, hexutil.Encode(consensusPayload.StateRoot), result.StateRoot)
+	require.Equal(t, hexutil.Encode(consensusPayload.ReceiptsRoot), result.ReceiptsRoot)
+	require.Equal(t, fmt.Sprintf("%d", consensusPayload.BlockNumber), result.BlockNumber)
+}
+
+// TestExecutionPayload_ToConsensus_HappyPath checks the
+// (*ExecutionPayload).ToConsensus function under normal conditions.
+func TestExecutionPayload_ToConsensus_HappyPath(t *testing.T) {
+	payload := &ExecutionPayload{
+		ParentHash:    hexutil.Encode(fillByteSlice(common.HashLength, 0xaa)),
+		FeeRecipient:  hexutil.Encode(fillByteSlice(20, 0xbb)),
+		StateRoot:     hexutil.Encode(fillByteSlice(32, 0xcc)),
+		ReceiptsRoot:  hexutil.Encode(fillByteSlice(32, 0xdd)),
+		LogsBloom:     hexutil.Encode(fillByteSlice(256, 0xee)),
+		PrevRandao:    hexutil.Encode(fillByteSlice(32, 0xff)),
+		BlockNumber:   "12345",
+		GasLimit:      "15000000",
+		GasUsed:       "8000000",
+		Timestamp:     "1680000000",
+		ExtraData:     "0x11111111",
+		BaseFeePerGas: "1234",
+		BlockHash:     hexutil.Encode(fillByteSlice(common.HashLength, 0x22)),
+		Transactions: []string{
+			hexutil.Encode(fillByteSlice(10, 0x33)),
+			hexutil.Encode(fillByteSlice(10, 0x44)),
+		},
+	}
+
+	result, err := payload.ToConsensus()
+	require.NoError(t, err)
+	require.DeepEqual(t, result.ParentHash, fillByteSlice(common.HashLength, 0xaa))
+	require.DeepEqual(t, result.FeeRecipient, fillByteSlice(20, 0xbb))
+	require.DeepEqual(t, result.StateRoot, fillByteSlice(32, 0xcc))
+}
+
+// TestExecutionPayloadHeaderFromConsensus_HappyPath checks the
+// ExecutionPayloadHeaderFromConsensus function under normal conditions.
+func TestExecutionPayloadHeaderFromConsensus_HappyPath(t *testing.T) {
+	consensusHeader := &enginev1.ExecutionPayloadHeader{
+		ParentHash:       fillByteSlice(common.HashLength, 0xaa),
+		FeeRecipient:     fillByteSlice(20, 0xbb),
+		StateRoot:        fillByteSlice(32, 0xcc),
+		ReceiptsRoot:     fillByteSlice(32, 0xdd),
+		LogsBloom:        fillByteSlice(256, 0xee),
+		PrevRandao:       fillByteSlice(32, 0xff),
+		BlockNumber:      9999,
+		GasLimit:         5000000,
+		GasUsed:          2500000,
+		Timestamp:        1111111111,
+		ExtraData:        fillByteSlice(4, 0x12),
+		BaseFeePerGas:    fillByteSlice(32, 0x34),
+		BlockHash:        fillByteSlice(common.HashLength, 0x56),
+		TransactionsRoot: fillByteSlice(32, 0x78),
+	}
+
+	result, err := ExecutionPayloadHeaderFromConsensus(consensusHeader)
+	require.NoError(t, err)
+	require.NotNil(t, result)
+	require.Equal(t, hexutil.Encode(consensusHeader.ParentHash), result.ParentHash)
+	require.Equal(t, fmt.Sprintf("%d", consensusHeader.BlockNumber), result.BlockNumber)
+}
+
+// TestExecutionPayloadHeader_ToConsensus_HappyPath checks the
+// (*ExecutionPayloadHeader).ToConsensus function under normal conditions.
+func TestExecutionPayloadHeader_ToConsensus_HappyPath(t *testing.T) {
+	header := &ExecutionPayloadHeader{
+		ParentHash:       hexutil.Encode(fillByteSlice(common.HashLength, 0xaa)),
+		FeeRecipient:     hexutil.Encode(fillByteSlice(20, 0xbb)),
+		StateRoot:        hexutil.Encode(fillByteSlice(32, 0xcc)),
+		ReceiptsRoot:     hexutil.Encode(fillByteSlice(32, 0xdd)),
+		LogsBloom:        hexutil.Encode(fillByteSlice(256, 0xee)),
+		PrevRandao:       hexutil.Encode(fillByteSlice(32, 0xff)),
+		BlockNumber:      "9999",
+		GasLimit:         "5000000",
+		GasUsed:          "2500000",
+		Timestamp:        "1111111111",
+		ExtraData:        "0x1234abcd",
+		BaseFeePerGas:    "1234",
+		BlockHash:        hexutil.Encode(fillByteSlice(common.HashLength, 0x56)),
+		TransactionsRoot: hexutil.Encode(fillByteSlice(32, 0x78)),
+	}
+
+	result, err := header.ToConsensus()
+	require.NoError(t, err)
+	require.DeepEqual(t, hexutil.Encode(result.ParentHash), header.ParentHash)
+	require.DeepEqual(t, hexutil.Encode(result.FeeRecipient), header.FeeRecipient)
+	require.DeepEqual(t, hexutil.Encode(result.StateRoot), header.StateRoot)
+}
+
+// TestExecutionPayloadCapellaFromConsensus_HappyPath checks the
+// ExecutionPayloadCapellaFromConsensus function under normal conditions.
+func TestExecutionPayloadCapellaFromConsensus_HappyPath(t *testing.T) {
+	capellaPayload := &enginev1.ExecutionPayloadCapella{
+		ParentHash:    fillByteSlice(common.HashLength, 0xaa),
+		FeeRecipient:  fillByteSlice(20, 0xbb),
+		StateRoot:     fillByteSlice(32, 0xcc),
+		ReceiptsRoot:  fillByteSlice(32, 0xdd),
+		LogsBloom:     fillByteSlice(256, 0xee),
+		PrevRandao:    fillByteSlice(32, 0xff),
+		BlockNumber:   123,
+		GasLimit:      9876543,
+		GasUsed:       1234567,
+		Timestamp:     5555555,
+		ExtraData:     fillByteSlice(6, 0x11),
+		BaseFeePerGas: fillByteSlice(32, 0x22),
+		BlockHash:     fillByteSlice(common.HashLength, 0x33),
+		Transactions: [][]byte{
+			fillByteSlice(5, 0x44),
+		},
+		Withdrawals: []*enginev1.Withdrawal{
+			{
+				Index:          1,
+				ValidatorIndex: 2,
+				Address:        fillByteSlice(20, 0xaa),
+				Amount:         100,
+			},
+		},
+	}
+
+	result, err := ExecutionPayloadCapellaFromConsensus(capellaPayload)
+	require.NoError(t, err)
+	require.NotNil(t, result)
+	require.Equal(t, hexutil.Encode(capellaPayload.ParentHash), result.ParentHash)
+	require.Equal(t, len(capellaPayload.Transactions), len(result.Transactions))
+	require.Equal(t, len(capellaPayload.Withdrawals), len(result.Withdrawals))
+}
+
+// TestExecutionPayloadCapella_ToConsensus_HappyPath checks the
+// (*ExecutionPayloadCapella).ToConsensus function under normal conditions.
+func TestExecutionPayloadCapella_ToConsensus_HappyPath(t *testing.T) {
+	capella := &ExecutionPayloadCapella{
+		ParentHash:    hexutil.Encode(fillByteSlice(common.HashLength, 0xaa)),
+		FeeRecipient:  hexutil.Encode(fillByteSlice(20, 0xbb)),
+		StateRoot:     hexutil.Encode(fillByteSlice(32, 0xcc)),
+		ReceiptsRoot:  hexutil.Encode(fillByteSlice(32, 0xdd)),
+		LogsBloom:     hexutil.Encode(fillByteSlice(256, 0xee)),
+		PrevRandao:    hexutil.Encode(fillByteSlice(32, 0xff)),
+		BlockNumber:   "123",
+		GasLimit:      "9876543",
+		GasUsed:       "1234567",
+		Timestamp:     "5555555",
+		ExtraData:     hexutil.Encode(fillByteSlice(6, 0x11)),
+		BaseFeePerGas: "1234",
+		BlockHash:     hexutil.Encode(fillByteSlice(common.HashLength, 0x33)),
+		Transactions: []string{
+			hexutil.Encode(fillByteSlice(5, 0x44)),
+		},
+		Withdrawals: []*Withdrawal{
+			{
+				WithdrawalIndex:  "1",
+				ValidatorIndex:   "2",
+				ExecutionAddress: hexutil.Encode(fillByteSlice(20, 0xaa)),
+				Amount:           "100",
+			},
+		},
+	}
+
+	result, err := capella.ToConsensus()
+	require.NoError(t, err)
+	require.DeepEqual(t, hexutil.Encode(result.ParentHash), capella.ParentHash)
+	require.DeepEqual(t, hexutil.Encode(result.FeeRecipient), capella.FeeRecipient)
+	require.DeepEqual(t, hexutil.Encode(result.StateRoot), capella.StateRoot)
+}
+
+// TestExecutionPayloadDenebFromConsensus_HappyPath checks the
+// ExecutionPayloadDenebFromConsensus function under normal conditions.
+func TestExecutionPayloadDenebFromConsensus_HappyPath(t *testing.T) {
+	denebPayload := &enginev1.ExecutionPayloadDeneb{
+		ParentHash:    fillByteSlice(common.HashLength, 0xaa),
+		FeeRecipient:  fillByteSlice(20, 0xbb),
+		StateRoot:     fillByteSlice(32, 0xcc),
+		ReceiptsRoot:  fillByteSlice(32, 0xdd),
+		LogsBloom:     fillByteSlice(256, 0xee),
+		PrevRandao:    fillByteSlice(32, 0xff),
+		BlockNumber:   999,
+		GasLimit:      2222222,
+		GasUsed:       1111111,
+		Timestamp:     666666,
+		ExtraData:     fillByteSlice(6, 0x11),
+		BaseFeePerGas: fillByteSlice(32, 0x22),
+		BlockHash:     fillByteSlice(common.HashLength, 0x33),
+		Transactions: [][]byte{
+			fillByteSlice(5, 0x44),
+		},
+		Withdrawals: []*enginev1.Withdrawal{
+			{
+				Index:          1,
+				ValidatorIndex: 2,
+				Address:        fillByteSlice(20, 0xaa),
+				Amount:         100,
+			},
+		},
+		BlobGasUsed:   1234,
+		ExcessBlobGas: 5678,
+	}
+
+	result, err := ExecutionPayloadDenebFromConsensus(denebPayload)
+	require.NoError(t, err)
+	require.Equal(t, hexutil.Encode(denebPayload.ParentHash), result.ParentHash)
+	require.Equal(t, len(denebPayload.Transactions), len(result.Transactions))
+	require.Equal(t, len(denebPayload.Withdrawals), len(result.Withdrawals))
+	require.Equal(t, "1234", result.BlobGasUsed)
+	require.Equal(t, fmt.Sprintf("%d", denebPayload.BlockNumber), result.BlockNumber)
+}
+
+// TestExecutionPayloadDeneb_ToConsensus_HappyPath checks the
+// (*ExecutionPayloadDeneb).ToConsensus function under normal conditions.
+func TestExecutionPayloadDeneb_ToConsensus_HappyPath(t *testing.T) {
+	deneb := &ExecutionPayloadDeneb{
+		ParentHash:    hexutil.Encode(fillByteSlice(common.HashLength, 0xaa)),
+		FeeRecipient:  hexutil.Encode(fillByteSlice(20, 0xbb)),
+		StateRoot:     hexutil.Encode(fillByteSlice(32, 0xcc)),
+		ReceiptsRoot:  hexutil.Encode(fillByteSlice(32, 0xdd)),
+		LogsBloom:     hexutil.Encode(fillByteSlice(256, 0xee)),
+		PrevRandao:    hexutil.Encode(fillByteSlice(32, 0xff)),
+		BlockNumber:   "999",
+		GasLimit:      "2222222",
+		GasUsed:       "1111111",
+		Timestamp:     "666666",
+		ExtraData:     hexutil.Encode(fillByteSlice(6, 0x11)),
+		BaseFeePerGas: "1234",
+		BlockHash:     hexutil.Encode(fillByteSlice(common.HashLength, 0x33)),
+		Transactions: []string{
+			hexutil.Encode(fillByteSlice(5, 0x44)),
+		},
+		Withdrawals: []*Withdrawal{
+			{
+				WithdrawalIndex:  "1",
+				ValidatorIndex:   "2",
+				ExecutionAddress: hexutil.Encode(fillByteSlice(20, 0xaa)),
+				Amount:           "100",
+			},
+		},
+		BlobGasUsed:   "1234",
+		ExcessBlobGas: "5678",
+	}
+
+	result, err := deneb.ToConsensus()
+	require.NoError(t, err)
+	require.DeepEqual(t, hexutil.Encode(result.ParentHash), deneb.ParentHash)
+	require.DeepEqual(t, hexutil.Encode(result.FeeRecipient), deneb.FeeRecipient)
+	require.Equal(t, result.BlockNumber, uint64(999))
+}
+
+func TestExecutionPayloadHeaderCapellaFromConsensus_HappyPath(t *testing.T) {
+	capellaHeader := &enginev1.ExecutionPayloadHeaderCapella{
+		ParentHash:       fillByteSlice(common.HashLength, 0xaa),
+		FeeRecipient:     fillByteSlice(20, 0xbb),
+		StateRoot:        fillByteSlice(32, 0xcc),
+		ReceiptsRoot:     fillByteSlice(32, 0xdd),
+		LogsBloom:        fillByteSlice(256, 0xee),
+		PrevRandao:       fillByteSlice(32, 0xff),
+		BlockNumber:      555,
+		GasLimit:         1111111,
+		GasUsed:          222222,
+		Timestamp:        3333333333,
+		ExtraData:        fillByteSlice(4, 0x12),
+		BaseFeePerGas:    fillByteSlice(32, 0x34),
+		BlockHash:        fillByteSlice(common.HashLength, 0x56),
+		TransactionsRoot: fillByteSlice(32, 0x78),
+		WithdrawalsRoot:  fillByteSlice(32, 0x99),
+	}
+
+	result, err := ExecutionPayloadHeaderCapellaFromConsensus(capellaHeader)
+	require.NoError(t, err)
+	require.Equal(t, hexutil.Encode(capellaHeader.ParentHash), result.ParentHash)
+	require.DeepEqual(t, hexutil.Encode(capellaHeader.WithdrawalsRoot), result.WithdrawalsRoot)
+}
+
+func TestExecutionPayloadHeaderCapella_ToConsensus_HappyPath(t *testing.T) {
+	header := &ExecutionPayloadHeaderCapella{
+		ParentHash:       hexutil.Encode(fillByteSlice(common.HashLength, 0xaa)),
+		FeeRecipient:     hexutil.Encode(fillByteSlice(20, 0xbb)),
+		StateRoot:        hexutil.Encode(fillByteSlice(32, 0xcc)),
+		ReceiptsRoot:     hexutil.Encode(fillByteSlice(32, 0xdd)),
+		LogsBloom:        hexutil.Encode(fillByteSlice(256, 0xee)),
+		PrevRandao:       hexutil.Encode(fillByteSlice(32, 0xff)),
+		BlockNumber:      "555",
+		GasLimit:         "1111111",
+		GasUsed:          "222222",
+		Timestamp:        "3333333333",
+		ExtraData:        "0x1234abcd",
+		BaseFeePerGas:    "1234",
+		BlockHash:        hexutil.Encode(fillByteSlice(common.HashLength, 0x56)),
+		TransactionsRoot: hexutil.Encode(fillByteSlice(32, 0x78)),
+		WithdrawalsRoot:  hexutil.Encode(fillByteSlice(32, 0x99)),
+	}
+
+	result, err := header.ToConsensus()
+	require.NoError(t, err)
+	require.DeepEqual(t, hexutil.Encode(result.ParentHash), header.ParentHash)
+	require.DeepEqual(t, hexutil.Encode(result.FeeRecipient), header.FeeRecipient)
+	require.DeepEqual(t, hexutil.Encode(result.StateRoot), header.StateRoot)
+	require.DeepEqual(t, hexutil.Encode(result.ReceiptsRoot), header.ReceiptsRoot)
+	require.DeepEqual(t, hexutil.Encode(result.WithdrawalsRoot), header.WithdrawalsRoot)
+}
+
+func TestExecutionPayloadHeaderDenebFromConsensus_HappyPath(t *testing.T) {
+	denebHeader := &enginev1.ExecutionPayloadHeaderDeneb{
+		ParentHash:       fillByteSlice(common.HashLength, 0xaa),
+		FeeRecipient:     fillByteSlice(20, 0xbb),
+		StateRoot:        fillByteSlice(32, 0xcc),
+		ReceiptsRoot:     fillByteSlice(32, 0xdd),
+		LogsBloom:        fillByteSlice(256, 0xee),
+		PrevRandao:       fillByteSlice(32, 0xff),
+		BlockNumber:      999,
+		GasLimit:         5000000,
+		GasUsed:          2500000,
+		Timestamp:        4444444444,
+		ExtraData:        fillByteSlice(4, 0x12),
+		BaseFeePerGas:    fillByteSlice(32, 0x34),
+		BlockHash:        fillByteSlice(common.HashLength, 0x56),
+		TransactionsRoot: fillByteSlice(32, 0x78),
+		WithdrawalsRoot:  fillByteSlice(32, 0x99),
+		BlobGasUsed:      1234,
+		ExcessBlobGas:    5678,
+	}
+
+	result, err := ExecutionPayloadHeaderDenebFromConsensus(denebHeader)
+	require.NoError(t, err)
+	require.Equal(t, hexutil.Encode(denebHeader.ParentHash), result.ParentHash)
+	require.DeepEqual(t, hexutil.Encode(denebHeader.FeeRecipient), result.FeeRecipient)
+	require.DeepEqual(t, hexutil.Encode(denebHeader.StateRoot), result.StateRoot)
+	require.DeepEqual(t, fmt.Sprintf("%d", denebHeader.BlobGasUsed), result.BlobGasUsed)
+}
+
+func TestExecutionPayloadHeaderDeneb_ToConsensus_HappyPath(t *testing.T) {
+	header := &ExecutionPayloadHeaderDeneb{
+		ParentHash:       hexutil.Encode(fillByteSlice(common.HashLength, 0xaa)),
+		FeeRecipient:     hexutil.Encode(fillByteSlice(20, 0xbb)),
+		StateRoot:        hexutil.Encode(fillByteSlice(32, 0xcc)),
+		ReceiptsRoot:     hexutil.Encode(fillByteSlice(32, 0xdd)),
+		LogsBloom:        hexutil.Encode(fillByteSlice(256, 0xee)),
+		PrevRandao:       hexutil.Encode(fillByteSlice(32, 0xff)),
+		BlockNumber:      "999",
+		GasLimit:         "5000000",
+		GasUsed:          "2500000",
+		Timestamp:        "4444444444",
+		ExtraData:        "0x1234abcd",
+		BaseFeePerGas:    "1234",
+		BlockHash:        hexutil.Encode(fillByteSlice(common.HashLength, 0x56)),
+		TransactionsRoot: hexutil.Encode(fillByteSlice(32, 0x78)),
+		WithdrawalsRoot:  hexutil.Encode(fillByteSlice(32, 0x99)),
+		BlobGasUsed:      "1234",
+		ExcessBlobGas:    "5678",
+	}
+
+	result, err := header.ToConsensus()
+	require.NoError(t, err)
+	require.DeepEqual(t, hexutil.Encode(result.ParentHash), header.ParentHash)
+	require.DeepEqual(t, result.BlobGasUsed, uint64(1234))
+	require.DeepEqual(t, result.ExcessBlobGas, uint64(5678))
+	require.DeepEqual(t, result.BlockNumber, uint64(999))
+}
+
+func TestWithdrawalRequestsFromConsensus_HappyPath(t *testing.T) {
+	consensusRequests := []*enginev1.WithdrawalRequest{
+		{
+			SourceAddress:   fillByteSlice(20, 0xbb),
+			ValidatorPubkey: fillByteSlice(48, 0xbb),
+			Amount:          12345,
+		},
+		{
+			SourceAddress:   fillByteSlice(20, 0xcc),
+			ValidatorPubkey: fillByteSlice(48, 0xcc),
+			Amount:          54321,
+		},
+	}
+
+	result := WithdrawalRequestsFromConsensus(consensusRequests)
+	require.DeepEqual(t, len(result), len(consensusRequests))
+	require.DeepEqual(t, result[0].Amount, fmt.Sprintf("%d", consensusRequests[0].Amount))
+}
+
+func TestWithdrawalRequestFromConsensus_HappyPath(t *testing.T) {
+	req := &enginev1.WithdrawalRequest{
+		SourceAddress:   fillByteSlice(20, 0xbb),
+		ValidatorPubkey: fillByteSlice(48, 0xbb),
+		Amount:          42,
+	}
+	result := WithdrawalRequestFromConsensus(req)
+	require.NotNil(t, result)
+	require.DeepEqual(t, result.SourceAddress, hexutil.Encode(fillByteSlice(20, 0xbb)))
+}
+
+func TestWithdrawalRequest_ToConsensus_HappyPath(t *testing.T) {
+	withdrawalReq := &WithdrawalRequest{
+		SourceAddress:   hexutil.Encode(fillByteSlice(20, 111)),
+		ValidatorPubkey: hexutil.Encode(fillByteSlice(48, 123)),
+		Amount:          "12345",
+	}
+	result, err := withdrawalReq.ToConsensus()
+	require.NoError(t, err)
+	require.DeepEqual(t, result.Amount, uint64(12345))
+}
+
+func TestConsolidationRequestsFromConsensus_HappyPath(t *testing.T) {
+	consensusRequests := []*enginev1.ConsolidationRequest{
+		{
+			SourceAddress: fillByteSlice(20, 111),
+			SourcePubkey:  fillByteSlice(48, 112),
+			TargetPubkey:  fillByteSlice(48, 113),
+		},
+	}
+	result := ConsolidationRequestsFromConsensus(consensusRequests)
+	require.DeepEqual(t, len(result), len(consensusRequests))
+	require.DeepEqual(t, result[0].SourceAddress, "0x6f6f6f6f6f6f6f6f6f6f6f6f6f6f6f6f6f6f6f6f")
+}
+
+func TestDepositRequestsFromConsensus_HappyPath(t *testing.T) {
+	ds := []*enginev1.DepositRequest{
+		{
+			Pubkey:                fillByteSlice(48, 0xbb),
+			WithdrawalCredentials: fillByteSlice(32, 0xdd),
+			Amount:                98765,
+			Signature:             fillByteSlice(96, 0xff),
+			Index:                 111,
+		},
+	}
+	result := DepositRequestsFromConsensus(ds)
+	require.DeepEqual(t, len(result), len(ds))
+	require.DeepEqual(t, result[0].Amount, "98765")
+}
+
+func TestDepositRequest_ToConsensus_HappyPath(t *testing.T) {
+	req := &DepositRequest{
+		Pubkey:                hexutil.Encode(fillByteSlice(48, 0xbb)),
+		WithdrawalCredentials: hexutil.Encode(fillByteSlice(32, 0xaa)),
+		Amount:                "123",
+		Signature:             hexutil.Encode(fillByteSlice(96, 0xdd)),
+		Index:                 "456",
+	}
+
+	result, err := req.ToConsensus()
+	require.NoError(t, err)
+	require.DeepEqual(t, result.Amount, uint64(123))
+	require.DeepEqual(t, result.Signature, fillByteSlice(96, 0xdd))
+}
+
+func TestExecutionRequestsFromConsensus_HappyPath(t *testing.T) {
+	er := &enginev1.ExecutionRequests{
+		Deposits: []*enginev1.DepositRequest{
+			{
+				Pubkey:                fillByteSlice(48, 0xba),
+				WithdrawalCredentials: fillByteSlice(32, 0xaa),
+				Amount:                33,
+				Signature:             fillByteSlice(96, 0xff),
+				Index:                 44,
+			},
+		},
+		Withdrawals: []*enginev1.WithdrawalRequest{
+			{
+				SourceAddress:   fillByteSlice(20, 0xaa),
+				ValidatorPubkey: fillByteSlice(48, 0xba),
+				Amount:          555,
+			},
+		},
+		Consolidations: []*enginev1.ConsolidationRequest{
+			{
+				SourceAddress: fillByteSlice(20, 0xdd),
+				SourcePubkey:  fillByteSlice(48, 0xdd),
+				TargetPubkey:  fillByteSlice(48, 0xcc),
+			},
+		},
+	}
+
+	result := ExecutionRequestsFromConsensus(er)
+	require.NotNil(t, result)
+	require.Equal(t, 1, len(result.Deposits))
+	require.Equal(t, "33", result.Deposits[0].Amount)
+	require.Equal(t, 1, len(result.Withdrawals))
+	require.Equal(t, "555", result.Withdrawals[0].Amount)
+	require.Equal(t, 1, len(result.Consolidations))
+	require.Equal(t, "0xcccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc", result.Consolidations[0].TargetPubkey)
+}
+
+func TestExecutionRequests_ToConsensus_HappyPath(t *testing.T) {
+	execReq := &ExecutionRequests{
+		Deposits: []*DepositRequest{
+			{
+				Pubkey:                hexutil.Encode(fillByteSlice(48, 0xbb)),
+				WithdrawalCredentials: hexutil.Encode(fillByteSlice(32, 0xaa)),
+				Amount:                "33",
+				Signature:             hexutil.Encode(fillByteSlice(96, 0xff)),
+				Index:                 "44",
+			},
+		},
+		Withdrawals: []*WithdrawalRequest{
+			{
+				SourceAddress:   hexutil.Encode(fillByteSlice(20, 0xdd)),
+				ValidatorPubkey: hexutil.Encode(fillByteSlice(48, 0xbb)),
+				Amount:          "555",
+			},
+		},
+		Consolidations: []*ConsolidationRequest{
+			{
+				SourceAddress: hexutil.Encode(fillByteSlice(20, 0xcc)),
+				SourcePubkey:  hexutil.Encode(fillByteSlice(48, 0xbb)),
+				TargetPubkey:  hexutil.Encode(fillByteSlice(48, 0xcc)),
+			},
+		},
+	}
+
+	result, err := execReq.ToConsensus()
+	require.NoError(t, err)
+
+	require.Equal(t, 1, len(result.Deposits))
+	require.Equal(t, uint64(33), result.Deposits[0].Amount)
+	require.Equal(t, 1, len(result.Withdrawals))
+	require.Equal(t, uint64(555), result.Withdrawals[0].Amount)
+	require.Equal(t, 1, len(result.Consolidations))
+	require.DeepEqual(t, fillByteSlice(48, 0xcc), result.Consolidations[0].TargetPubkey)
+}

api/server/structs/conversions_lightclient.go

@@ -0,0 +1,229 @@
+package structs
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
+	enginev1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
+	"github.com/OffchainLabs/prysm/v6/runtime/version"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/pkg/errors"
+)
+
+func LightClientUpdateFromConsensus(update interfaces.LightClientUpdate) (*LightClientUpdate, error) {
+	attestedHeader, err := lightClientHeaderToJSON(update.AttestedHeader())
+	if err != nil {
+		return nil, errors.Wrap(err, "could not marshal attested light client header")
+	}
+	finalizedHeader, err := lightClientHeaderToJSON(update.FinalizedHeader())
+	if err != nil {
+		return nil, errors.Wrap(err, "could not marshal finalized light client header")
+	}
+
+	var scBranch [][32]byte
+	var finalityBranch [][32]byte
+	if update.Version() >= version.Electra {
+		scb, err := update.NextSyncCommitteeBranchElectra()
+		if err != nil {
+			return nil, err
+		}
+		scBranch = scb[:]
+		fb, err := update.FinalityBranchElectra()
+		if err != nil {
+			return nil, err
+		}
+		finalityBranch = fb[:]
+	} else {
+		scb, err := update.NextSyncCommitteeBranch()
+		if err != nil {
+			return nil, err
+		}
+		scBranch = scb[:]
+		fb, err := update.FinalityBranch()
+		if err != nil {
+			return nil, err
+		}
+		finalityBranch = fb[:]
+	}
+
+	return &LightClientUpdate{
+		AttestedHeader:          attestedHeader,
+		NextSyncCommittee:       SyncCommitteeFromConsensus(update.NextSyncCommittee()),
+		NextSyncCommitteeBranch: branchToJSON(scBranch),
+		FinalizedHeader:         finalizedHeader,
+		FinalityBranch:          branchToJSON(finalityBranch),
+		SyncAggregate:           SyncAggregateFromConsensus(update.SyncAggregate()),
+		SignatureSlot:           fmt.Sprintf("%d", update.SignatureSlot()),
+	}, nil
+}
+
+func LightClientFinalityUpdateFromConsensus(update interfaces.LightClientFinalityUpdate) (*LightClientFinalityUpdate, error) {
+	attestedHeader, err := lightClientHeaderToJSON(update.AttestedHeader())
+	if err != nil {
+		return nil, errors.Wrap(err, "could not marshal attested light client header")
+	}
+	finalizedHeader, err := lightClientHeaderToJSON(update.FinalizedHeader())
+	if err != nil {
+		return nil, errors.Wrap(err, "could not marshal finalized light client header")
+	}
+
+	var finalityBranch [][32]byte
+	if update.Version() >= version.Electra {
+		b, err := update.FinalityBranchElectra()
+		if err != nil {
+			return nil, err
+		}
+		finalityBranch = b[:]
+	} else {
+		b, err := update.FinalityBranch()
+		if err != nil {
+			return nil, err
+		}
+		finalityBranch = b[:]
+	}
+
+	return &LightClientFinalityUpdate{
+		AttestedHeader:  attestedHeader,
+		FinalizedHeader: finalizedHeader,
+		FinalityBranch:  branchToJSON(finalityBranch),
+		SyncAggregate:   SyncAggregateFromConsensus(update.SyncAggregate()),
+		SignatureSlot:   fmt.Sprintf("%d", update.SignatureSlot()),
+	}, nil
+}
+
+func LightClientOptimisticUpdateFromConsensus(update interfaces.LightClientOptimisticUpdate) (*LightClientOptimisticUpdate, error) {
+	attestedHeader, err := lightClientHeaderToJSON(update.AttestedHeader())
+	if err != nil {
+		return nil, errors.Wrap(err, "could not marshal attested light client header")
+	}
+
+	return &LightClientOptimisticUpdate{
+		AttestedHeader: attestedHeader,
+		SyncAggregate:  SyncAggregateFromConsensus(update.SyncAggregate()),
+		SignatureSlot:  fmt.Sprintf("%d", update.SignatureSlot()),
+	}, nil
+}
+
+func branchToJSON[S [][32]byte](branchBytes S) []string {
+	if branchBytes == nil {
+		return nil
+	}
+	branch := make([]string, len(branchBytes))
+	for i, root := range branchBytes {
+		branch[i] = hexutil.Encode(root[:])
+	}
+	return branch
+}
+
+func lightClientHeaderToJSON(header interfaces.LightClientHeader) (json.RawMessage, error) {
+	// In the case that a finalizedHeader is nil.
+	if header == nil {
+		return nil, nil
+	}
+
+	var result any
+
+	switch v := header.Version(); v {
+	case version.Altair:
+		result = &LightClientHeader{Beacon: BeaconBlockHeaderFromConsensus(header.Beacon())}
+	case version.Capella:
+		exInterface, err := header.Execution()
+		if err != nil {
+			return nil, err
+		}
+		ex, ok := exInterface.Proto().(*enginev1.ExecutionPayloadHeaderCapella)
+		if !ok {
+			return nil, fmt.Errorf("execution data is not %T", &enginev1.ExecutionPayloadHeaderCapella{})
+		}
+		execution, err := ExecutionPayloadHeaderCapellaFromConsensus(ex)
+		if err != nil {
+			return nil, err
+		}
+		executionBranch, err := header.ExecutionBranch()
+		if err != nil {
+			return nil, err
+		}
+		result = &LightClientHeaderCapella{
+			Beacon:          BeaconBlockHeaderFromConsensus(header.Beacon()),
+			Execution:       execution,
+			ExecutionBranch: branchToJSON(executionBranch[:]),
+		}
+	case version.Deneb:
+		exInterface, err := header.Execution()
+		if err != nil {
+			return nil, err
+		}
+		ex, ok := exInterface.Proto().(*enginev1.ExecutionPayloadHeaderDeneb)
+		if !ok {
+			return nil, fmt.Errorf("execution data is not %T", &enginev1.ExecutionPayloadHeaderDeneb{})
+		}
+		execution, err := ExecutionPayloadHeaderDenebFromConsensus(ex)
+		if err != nil {
+			return nil, err
+		}
+		executionBranch, err := header.ExecutionBranch()
+		if err != nil {
+			return nil, err
+		}
+		result = &LightClientHeaderDeneb{
+			Beacon:          BeaconBlockHeaderFromConsensus(header.Beacon()),
+			Execution:       execution,
+			ExecutionBranch: branchToJSON(executionBranch[:]),
+		}
+	case version.Electra:
+		exInterface, err := header.Execution()
+		if err != nil {
+			return nil, err
+		}
+		ex, ok := exInterface.Proto().(*enginev1.ExecutionPayloadHeaderDeneb)
+		if !ok {
+			return nil, fmt.Errorf("execution data is not %T", &enginev1.ExecutionPayloadHeaderDeneb{})
+		}
+		execution, err := ExecutionPayloadHeaderElectraFromConsensus(ex)
+		if err != nil {
+			return nil, err
+		}
+		executionBranch, err := header.ExecutionBranch()
+		if err != nil {
+			return nil, err
+		}
+		result = &LightClientHeaderDeneb{
+			Beacon:          BeaconBlockHeaderFromConsensus(header.Beacon()),
+			Execution:       execution,
+			ExecutionBranch: branchToJSON(executionBranch[:]),
+		}
+	default:
+		return nil, fmt.Errorf("unsupported header version %s", version.String(v))
+	}
+
+	return json.Marshal(result)
+}
+
+func LightClientBootstrapFromConsensus(bootstrap interfaces.LightClientBootstrap) (*LightClientBootstrap, error) {
+	header, err := lightClientHeaderToJSON(bootstrap.Header())
+	if err != nil {
+		return nil, errors.Wrap(err, "could not marshal light client header")
+	}
+
+	var scBranch [][32]byte
+	if bootstrap.Version() >= version.Electra {
+		b, err := bootstrap.CurrentSyncCommitteeBranchElectra()
+		if err != nil {
+			return nil, err
+		}
+		scBranch = b[:]
+	} else {
+		b, err := bootstrap.CurrentSyncCommitteeBranch()
+		if err != nil {
+			return nil, err
+		}
+		scBranch = b[:]
+	}
+
+	return &LightClientBootstrap{
+		Header:                     header,
+		CurrentSyncCommittee:       SyncCommitteeFromConsensus(bootstrap.CurrentSyncCommittee()),
+		CurrentSyncCommitteeBranch: branchToJSON(scBranch),
+	}, nil
+}

api/server/structs/conversions_state.go

@@ -4,13 +4,17 @@ import (
 	"errors"
 	"fmt"
 
+	beaconState "github.com/OffchainLabs/prysm/v6/beacon-chain/state"
+	enginev1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
 	"github.com/ethereum/go-ethereum/common/hexutil"
-	beaconState "github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	enginev1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
 )
 
 var errPayloadHeaderNotFound = errors.New("expected payload header not found")
 
+// ----------------------------------------------------------------------------
+// Phase 0
+// ----------------------------------------------------------------------------
+
 func BeaconStateFromConsensus(st beaconState.BeaconState) (*BeaconState, error) {
 	srcBr := st.BlockRoots()
 	br := make([]string, len(srcBr))
@@ -97,6 +101,10 @@ func BeaconStateFromConsensus(st beaconState.BeaconState) (*BeaconState, error)
 	}, nil
 }
 
+// ----------------------------------------------------------------------------
+// Altair
+// ----------------------------------------------------------------------------
+
 func BeaconStateAltairFromConsensus(st beaconState.BeaconState) (*BeaconStateAltair, error) {
 	srcBr := st.BlockRoots()
 	br := make([]string, len(srcBr))
@@ -202,6 +210,10 @@ func BeaconStateAltairFromConsensus(st beaconState.BeaconState) (*BeaconStateAlt
 	}, nil
 }
 
+// ----------------------------------------------------------------------------
+// Bellatrix
+// ----------------------------------------------------------------------------
+
 func BeaconStateBellatrixFromConsensus(st beaconState.BeaconState) (*BeaconStateBellatrix, error) {
 	srcBr := st.BlockRoots()
 	br := make([]string, len(srcBr))
@@ -320,6 +332,10 @@ func BeaconStateBellatrixFromConsensus(st beaconState.BeaconState) (*BeaconState
 	}, nil
 }
 
+// ----------------------------------------------------------------------------
+// Capella
+// ----------------------------------------------------------------------------
+
 func BeaconStateCapellaFromConsensus(st beaconState.BeaconState) (*BeaconStateCapella, error) {
 	srcBr := st.BlockRoots()
 	br := make([]string, len(srcBr))
@@ -457,6 +473,10 @@ func BeaconStateCapellaFromConsensus(st beaconState.BeaconState) (*BeaconStateCa
 	}, nil
 }
 
+// ----------------------------------------------------------------------------
+// Deneb
+// ----------------------------------------------------------------------------
+
 func BeaconStateDenebFromConsensus(st beaconState.BeaconState) (*BeaconStateDeneb, error) {
 	srcBr := st.BlockRoots()
 	br := make([]string, len(srcBr))
@@ -593,3 +613,375 @@ func BeaconStateDenebFromConsensus(st beaconState.BeaconState) (*BeaconStateDene
 		HistoricalSummaries:          hs,
 	}, nil
 }
+
+// ----------------------------------------------------------------------------
+// Electra
+// ----------------------------------------------------------------------------
+
+func BeaconStateElectraFromConsensus(st beaconState.BeaconState) (*BeaconStateElectra, error) {
+	srcBr := st.BlockRoots()
+	br := make([]string, len(srcBr))
+	for i, r := range srcBr {
+		br[i] = hexutil.Encode(r)
+	}
+	srcSr := st.StateRoots()
+	sr := make([]string, len(srcSr))
+	for i, r := range srcSr {
+		sr[i] = hexutil.Encode(r)
+	}
+	srcHr, err := st.HistoricalRoots()
+	if err != nil {
+		return nil, err
+	}
+	hr := make([]string, len(srcHr))
+	for i, r := range srcHr {
+		hr[i] = hexutil.Encode(r)
+	}
+	srcVotes := st.Eth1DataVotes()
+	votes := make([]*Eth1Data, len(srcVotes))
+	for i, e := range srcVotes {
+		votes[i] = Eth1DataFromConsensus(e)
+	}
+	srcVals := st.Validators()
+	vals := make([]*Validator, len(srcVals))
+	for i, v := range srcVals {
+		vals[i] = ValidatorFromConsensus(v)
+	}
+	srcBals := st.Balances()
+	bals := make([]string, len(srcBals))
+	for i, b := range srcBals {
+		bals[i] = fmt.Sprintf("%d", b)
+	}
+	srcRm := st.RandaoMixes()
+	rm := make([]string, len(srcRm))
+	for i, m := range srcRm {
+		rm[i] = hexutil.Encode(m)
+	}
+	srcSlashings := st.Slashings()
+	slashings := make([]string, len(srcSlashings))
+	for i, s := range srcSlashings {
+		slashings[i] = fmt.Sprintf("%d", s)
+	}
+	srcPrevPart, err := st.PreviousEpochParticipation()
+	if err != nil {
+		return nil, err
+	}
+	prevPart := make([]string, len(srcPrevPart))
+	for i, p := range srcPrevPart {
+		prevPart[i] = fmt.Sprintf("%d", p)
+	}
+	srcCurrPart, err := st.CurrentEpochParticipation()
+	if err != nil {
+		return nil, err
+	}
+	currPart := make([]string, len(srcCurrPart))
+	for i, p := range srcCurrPart {
+		currPart[i] = fmt.Sprintf("%d", p)
+	}
+	srcIs, err := st.InactivityScores()
+	if err != nil {
+		return nil, err
+	}
+	is := make([]string, len(srcIs))
+	for i, s := range srcIs {
+		is[i] = fmt.Sprintf("%d", s)
+	}
+	currSc, err := st.CurrentSyncCommittee()
+	if err != nil {
+		return nil, err
+	}
+	nextSc, err := st.NextSyncCommittee()
+	if err != nil {
+		return nil, err
+	}
+	execData, err := st.LatestExecutionPayloadHeader()
+	if err != nil {
+		return nil, err
+	}
+	srcPayload, ok := execData.Proto().(*enginev1.ExecutionPayloadHeaderDeneb)
+	if !ok {
+		return nil, errPayloadHeaderNotFound
+	}
+	payload, err := ExecutionPayloadHeaderElectraFromConsensus(srcPayload)
+	if err != nil {
+		return nil, err
+	}
+	srcHs, err := st.HistoricalSummaries()
+	if err != nil {
+		return nil, err
+	}
+	hs := make([]*HistoricalSummary, len(srcHs))
+	for i, s := range srcHs {
+		hs[i] = HistoricalSummaryFromConsensus(s)
+	}
+	nwi, err := st.NextWithdrawalIndex()
+	if err != nil {
+		return nil, err
+	}
+	nwvi, err := st.NextWithdrawalValidatorIndex()
+	if err != nil {
+		return nil, err
+	}
+	drsi, err := st.DepositRequestsStartIndex()
+	if err != nil {
+		return nil, err
+	}
+	dbtc, err := st.DepositBalanceToConsume()
+	if err != nil {
+		return nil, err
+	}
+	ebtc, err := st.ExitBalanceToConsume()
+	if err != nil {
+		return nil, err
+	}
+	eee, err := st.EarliestExitEpoch()
+	if err != nil {
+		return nil, err
+	}
+	cbtc, err := st.ConsolidationBalanceToConsume()
+	if err != nil {
+		return nil, err
+	}
+	ece, err := st.EarliestConsolidationEpoch()
+	if err != nil {
+		return nil, err
+	}
+	pbd, err := st.PendingDeposits()
+	if err != nil {
+		return nil, err
+	}
+	ppw, err := st.PendingPartialWithdrawals()
+	if err != nil {
+		return nil, err
+	}
+	pc, err := st.PendingConsolidations()
+	if err != nil {
+		return nil, err
+	}
+
+	return &BeaconStateElectra{
+		GenesisTime:                   fmt.Sprintf("%d", st.GenesisTime()),
+		GenesisValidatorsRoot:         hexutil.Encode(st.GenesisValidatorsRoot()),
+		Slot:                          fmt.Sprintf("%d", st.Slot()),
+		Fork:                          ForkFromConsensus(st.Fork()),
+		LatestBlockHeader:             BeaconBlockHeaderFromConsensus(st.LatestBlockHeader()),
+		BlockRoots:                    br,
+		StateRoots:                    sr,
+		HistoricalRoots:               hr,
+		Eth1Data:                      Eth1DataFromConsensus(st.Eth1Data()),
+		Eth1DataVotes:                 votes,
+		Eth1DepositIndex:              fmt.Sprintf("%d", st.Eth1DepositIndex()),
+		Validators:                    vals,
+		Balances:                      bals,
+		RandaoMixes:                   rm,
+		Slashings:                     slashings,
+		PreviousEpochParticipation:    prevPart,
+		CurrentEpochParticipation:     currPart,
+		JustificationBits:             hexutil.Encode(st.JustificationBits()),
+		PreviousJustifiedCheckpoint:   CheckpointFromConsensus(st.PreviousJustifiedCheckpoint()),
+		CurrentJustifiedCheckpoint:    CheckpointFromConsensus(st.CurrentJustifiedCheckpoint()),
+		FinalizedCheckpoint:           CheckpointFromConsensus(st.FinalizedCheckpoint()),
+		InactivityScores:              is,
+		CurrentSyncCommittee:          SyncCommitteeFromConsensus(currSc),
+		NextSyncCommittee:             SyncCommitteeFromConsensus(nextSc),
+		LatestExecutionPayloadHeader:  payload,
+		NextWithdrawalIndex:           fmt.Sprintf("%d", nwi),
+		NextWithdrawalValidatorIndex:  fmt.Sprintf("%d", nwvi),
+		HistoricalSummaries:           hs,
+		DepositRequestsStartIndex:     fmt.Sprintf("%d", drsi),
+		DepositBalanceToConsume:       fmt.Sprintf("%d", dbtc),
+		ExitBalanceToConsume:          fmt.Sprintf("%d", ebtc),
+		EarliestExitEpoch:             fmt.Sprintf("%d", eee),
+		ConsolidationBalanceToConsume: fmt.Sprintf("%d", cbtc),
+		EarliestConsolidationEpoch:    fmt.Sprintf("%d", ece),
+		PendingDeposits:               PendingDepositsFromConsensus(pbd),
+		PendingPartialWithdrawals:     PendingPartialWithdrawalsFromConsensus(ppw),
+		PendingConsolidations:         PendingConsolidationsFromConsensus(pc),
+	}, nil
+}
+
+// ----------------------------------------------------------------------------
+// Fulu
+// ----------------------------------------------------------------------------
+
+func BeaconStateFuluFromConsensus(st beaconState.BeaconState) (*BeaconStateFulu, error) {
+	srcBr := st.BlockRoots()
+	br := make([]string, len(srcBr))
+	for i, r := range srcBr {
+		br[i] = hexutil.Encode(r)
+	}
+	srcSr := st.StateRoots()
+	sr := make([]string, len(srcSr))
+	for i, r := range srcSr {
+		sr[i] = hexutil.Encode(r)
+	}
+	srcHr, err := st.HistoricalRoots()
+	if err != nil {
+		return nil, err
+	}
+	hr := make([]string, len(srcHr))
+	for i, r := range srcHr {
+		hr[i] = hexutil.Encode(r)
+	}
+	srcVotes := st.Eth1DataVotes()
+	votes := make([]*Eth1Data, len(srcVotes))
+	for i, e := range srcVotes {
+		votes[i] = Eth1DataFromConsensus(e)
+	}
+	srcVals := st.Validators()
+	vals := make([]*Validator, len(srcVals))
+	for i, v := range srcVals {
+		vals[i] = ValidatorFromConsensus(v)
+	}
+	srcBals := st.Balances()
+	bals := make([]string, len(srcBals))
+	for i, b := range srcBals {
+		bals[i] = fmt.Sprintf("%d", b)
+	}
+	srcRm := st.RandaoMixes()
+	rm := make([]string, len(srcRm))
+	for i, m := range srcRm {
+		rm[i] = hexutil.Encode(m)
+	}
+	srcSlashings := st.Slashings()
+	slashings := make([]string, len(srcSlashings))
+	for i, s := range srcSlashings {
+		slashings[i] = fmt.Sprintf("%d", s)
+	}
+	srcPrevPart, err := st.PreviousEpochParticipation()
+	if err != nil {
+		return nil, err
+	}
+	prevPart := make([]string, len(srcPrevPart))
+	for i, p := range srcPrevPart {
+		prevPart[i] = fmt.Sprintf("%d", p)
+	}
+	srcCurrPart, err := st.CurrentEpochParticipation()
+	if err != nil {
+		return nil, err
+	}
+	currPart := make([]string, len(srcCurrPart))
+	for i, p := range srcCurrPart {
+		currPart[i] = fmt.Sprintf("%d", p)
+	}
+	srcIs, err := st.InactivityScores()
+	if err != nil {
+		return nil, err
+	}
+	is := make([]string, len(srcIs))
+	for i, s := range srcIs {
+		is[i] = fmt.Sprintf("%d", s)
+	}
+	currSc, err := st.CurrentSyncCommittee()
+	if err != nil {
+		return nil, err
+	}
+	nextSc, err := st.NextSyncCommittee()
+	if err != nil {
+		return nil, err
+	}
+	execData, err := st.LatestExecutionPayloadHeader()
+	if err != nil {
+		return nil, err
+	}
+	srcPayload, ok := execData.Proto().(*enginev1.ExecutionPayloadHeaderDeneb)
+	if !ok {
+		return nil, errPayloadHeaderNotFound
+	}
+	payload, err := ExecutionPayloadHeaderElectraFromConsensus(srcPayload)
+	if err != nil {
+		return nil, err
+	}
+	srcHs, err := st.HistoricalSummaries()
+	if err != nil {
+		return nil, err
+	}
+	hs := make([]*HistoricalSummary, len(srcHs))
+	for i, s := range srcHs {
+		hs[i] = HistoricalSummaryFromConsensus(s)
+	}
+	nwi, err := st.NextWithdrawalIndex()
+	if err != nil {
+		return nil, err
+	}
+	nwvi, err := st.NextWithdrawalValidatorIndex()
+	if err != nil {
+		return nil, err
+	}
+	drsi, err := st.DepositRequestsStartIndex()
+	if err != nil {
+		return nil, err
+	}
+	dbtc, err := st.DepositBalanceToConsume()
+	if err != nil {
+		return nil, err
+	}
+	ebtc, err := st.ExitBalanceToConsume()
+	if err != nil {
+		return nil, err
+	}
+	eee, err := st.EarliestExitEpoch()
+	if err != nil {
+		return nil, err
+	}
+	cbtc, err := st.ConsolidationBalanceToConsume()
+	if err != nil {
+		return nil, err
+	}
+	ece, err := st.EarliestConsolidationEpoch()
+	if err != nil {
+		return nil, err
+	}
+	pbd, err := st.PendingDeposits()
+	if err != nil {
+		return nil, err
+	}
+	ppw, err := st.PendingPartialWithdrawals()
+	if err != nil {
+		return nil, err
+	}
+	pc, err := st.PendingConsolidations()
+	if err != nil {
+		return nil, err
+	}
+
+	return &BeaconStateFulu{
+		GenesisTime:                   fmt.Sprintf("%d", st.GenesisTime()),
+		GenesisValidatorsRoot:         hexutil.Encode(st.GenesisValidatorsRoot()),
+		Slot:                          fmt.Sprintf("%d", st.Slot()),
+		Fork:                          ForkFromConsensus(st.Fork()),
+		LatestBlockHeader:             BeaconBlockHeaderFromConsensus(st.LatestBlockHeader()),
+		BlockRoots:                    br,
+		StateRoots:                    sr,
+		HistoricalRoots:               hr,
+		Eth1Data:                      Eth1DataFromConsensus(st.Eth1Data()),
+		Eth1DataVotes:                 votes,
+		Eth1DepositIndex:              fmt.Sprintf("%d", st.Eth1DepositIndex()),
+		Validators:                    vals,
+		Balances:                      bals,
+		RandaoMixes:                   rm,
+		Slashings:                     slashings,
+		PreviousEpochParticipation:    prevPart,
+		CurrentEpochParticipation:     currPart,
+		JustificationBits:             hexutil.Encode(st.JustificationBits()),
+		PreviousJustifiedCheckpoint:   CheckpointFromConsensus(st.PreviousJustifiedCheckpoint()),
+		CurrentJustifiedCheckpoint:    CheckpointFromConsensus(st.CurrentJustifiedCheckpoint()),
+		FinalizedCheckpoint:           CheckpointFromConsensus(st.FinalizedCheckpoint()),
+		InactivityScores:              is,
+		CurrentSyncCommittee:          SyncCommitteeFromConsensus(currSc),
+		NextSyncCommittee:             SyncCommitteeFromConsensus(nextSc),
+		LatestExecutionPayloadHeader:  payload,
+		NextWithdrawalIndex:           fmt.Sprintf("%d", nwi),
+		NextWithdrawalValidatorIndex:  fmt.Sprintf("%d", nwvi),
+		HistoricalSummaries:           hs,
+		DepositRequestsStartIndex:     fmt.Sprintf("%d", drsi),
+		DepositBalanceToConsume:       fmt.Sprintf("%d", dbtc),
+		ExitBalanceToConsume:          fmt.Sprintf("%d", ebtc),
+		EarliestExitEpoch:             fmt.Sprintf("%d", eee),
+		ConsolidationBalanceToConsume: fmt.Sprintf("%d", cbtc),
+		EarliestConsolidationEpoch:    fmt.Sprintf("%d", ece),
+		PendingDeposits:               PendingDepositsFromConsensus(pbd),
+		PendingPartialWithdrawals:     PendingPartialWithdrawalsFromConsensus(ppw),
+		PendingConsolidations:         PendingConsolidationsFromConsensus(pc),
+	}, nil
+}