fixing beacon

fixing grpc issue
merging apiutil and httputil
2026-01-10 05:47:59 -05:00 · 2025-04-03 16:15:56 -05:00 · 2025-04-03 15:26:29 -05:00 · 2025-04-03 15:20:04 -05:00 · 2025-04-03 15:17:55 -05:00 · 2025-04-03 15:14:14 -05:00
552 changed files with 12008 additions and 5852 deletions
--- a/.github/actions/gomodtidy/Dockerfile
+++ b/.github/actions/gomodtidy/Dockerfile
@@ -1,4 +1,4 @@
-FROM golang:1.23-alpine
+FROM golang:1.24-alpine

 COPY entrypoint.sh /entrypoint.sh

--- a/.github/workflows/changelog.yml
+++ b/.github/workflows/changelog.yml
@@ -12,7 +12,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout source code
-        uses: actions/checkout@v3
+        uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0

      - name: Download unclog binary
        uses: dsaltares/fetch-gh-release-asset@aa2ab1243d6e0d5b405b973c89fa4d06a2d0fff7 # 1.1.2
@@ -23,7 +23,7 @@ jobs:

      - name: Get new changelog files
        id: new-changelog-files
-        uses: tj-actions/changed-files@v45
+        uses: OffchainLabs/gh-action-changed-files@9200e69727eb73eb060652b19946b8a2fdfb654b # v4.0.8
        with:
          files: |
            changelog/**.md
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -28,15 +28,15 @@ jobs:
    steps:
      - name: Checkout
        uses: actions/checkout@v4
-      - name: Set up Go 1.23
+      - name: Set up Go 1.24
        uses: actions/setup-go@v4
        with:
-          go-version: '1.23.5'
+          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@v2.19.0
-          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
@@ -45,16 +45,16 @@ jobs:
      - name: Checkout
        uses: actions/checkout@v4

-      - name: Set up Go 1.23
+      - name: Set up Go 1.24
        uses: actions/setup-go@v4
        with:
-          go-version: '1.23.5'
+          go-version: '1.24.0'
          id: go

      - name: Golangci-lint
        uses: golangci/golangci-lint-action@v5
        with:
-          version: v1.63.4
+          version: v1.64.5
          args: --config=.golangci.yml --out-${NO_FUTURE}format colored-line-number

  build:
@@ -64,7 +64,7 @@ jobs:
      - name: Set up Go 1.x
        uses: actions/setup-go@v4
        with:
-          go-version: '1.23.5'
+          go-version: '1.24.0'
        id: go

      - name: Check out code into the Go module directory
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -75,6 +75,7 @@ linters:
    - tagliatelle
    - thelper
    - unparam
+    - usetesting
    - varnamelen
    - wrapcheck
    - wsl
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -165,7 +165,7 @@ STATICCHECK_ANALYZERS = [
    "sa6006",
    "sa9001",
    "sa9002",
-    #"sa9003", # Doesn't build. See https://github.com/dominikh/go-tools/pull/1483
+    "sa9003",
    "sa9004",
    "sa9005",
    "sa9006",
@@ -197,6 +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",
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,139 @@ All notable changes to this project will be documented in this file.

 The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

+## [v5.3.2](https://github.com/prysmaticlabs/prysm/compare/v5.3.1...v5.3.2) - 2025-03-25
+
+This release introduces support for the `Hoodi` testnet.
+
+Release highlights:
+
+- Ability to run the node on the `Hoodi` tesnet. See https://blog.ethereum.org/2025/03/18/hoodi-holesky for more information about `Hoodi`.
+- A new feature that allows treat certain blocks as invalid. This is especially useful when the network is split, allowing the node to discontinue following unwanted forks.
+
+Testnet operators are required to update to this release. Without this release you will be unable to run the node on the `Hoodi` testnet.
+
+Mainnet operators are recommended to update to this release at their regular cadence.
+
+### Added
+
+- enable SSZ for builder API calls. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14976)
+- Add Hoodi testnet flag `--hoodi` to specify Hoodi testnet config and bootnodes. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15057)
+- block_gossip topic support to the beacon api event stream. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15038)
+- Added a static analyzer to discourage use of panic() in Prysm. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15075)
+- Add a feature flag `--blacklist-roots` to allow the node to specify blocks that will be treated as invalid. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15030)
+
+### Changed
+
+- changed request object for `POST /eth/v1/beacon/states/head/validators` to omit the field if empty for satisfying other clients. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15031)
+- Update spec test to v1.5.0-beta.3. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15050)
+- Update Gossip and RPC message limits to comply with the spec. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14799)
+- Return 404 instead of 500 from API when when a blob for a requested index is not found. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14845)
+- Save Electra orphaned attestations into attestations pool's block attestations. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15060)
+- Removed redundant string conversion in `BeaconDbStater.State` to improve code clarity and maintainability. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15081)
+
+### Fixed
+
+- Update seen unaggregated att cache to properly handle Electra attestations. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15034)
+- cosmetic fix for calling `/prysm/validators/performance` when connecting to non prysm beacon nodes and removing the 404 error log. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15062)
+- Tracked validator cache: Make sure no to loose the reference. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15077)
+- Fixed proposing at genesis when starting post Bellatrix. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15084)
+
+## [v5.3.1](https://github.com/prysmaticlabs/prysm/compare/v5.3.0...v5.3.1) - 2025-03-13
+
+This release is packed with critical fixes for **Electra** and some important fixes for mainnet too. 
+
+The release highlights include:
+
+- Ensure that deleting a block from the database clears its entry in the slot->root db index. This issue was causing some operators to have a bricked database, requiring a full resync. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15011)
+- Updated go to go1.24.0. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14969)
+- Added a feature flag to sync from an arbitrary beacon block root at startup. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15000)
+- Updated default gas limit from 30M to 36M. Override this with `--suggested-gas-limit=` in the validator client. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14858)
+
+Known issues in **Electra**:
+
+- Duplicate attestations are needlessly processed. This is being addressed in [[PR]](https://github.com/prysmaticlabs/prysm/pull/15034).
+
+Testnet operators are strongly encouraged to update to this release. There are many fixes and improvements from the Holesky upgrade incident.
+
+Mainnet operators are recommended to update to this release at their regular cadence. 
+
+### Added
+
+- enable E2E for minimal and mainnet tests. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14842)
+- enable web3signer E2E for electra. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14936)
+- Enable multiclient E2E for electra. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14946)
+- Enable Scenario E2E tests with electra. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14946)
+- Add endpoint for getting pending deposits. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14941)
+- Add request hash to header for builder: executable data to block. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14955)
+- Log execution requests in each block. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14956)
+- Add endpoint for getting pending partial withdrawals. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14949)
+- Tracked validators cache: Added the `ItemCount` method. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14957)
+- Tracked validators cache: Added the `Indices` method. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14957)
+- Added deposit request testing for electra. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14964)
+- Added support for otel tracing transport in HTTP clients in Prysm. This allows for tracing headers to be sent with http requests such that spans between the validator and beacon chain can be connected in the tracing graph. This change does nothing without `--enable-tracing`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14972)
+- Add SSZ support to light client finality and optimistic APIs. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14836)
+- add log to committee index when committeebits are not the expected length of 1. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14993)
+- Add acceptable address types for static peers. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14886)
+- Added a feature flag to sync from an arbitrary beacon block root at startup. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15000)
+
+### Changed
+
+- updates geth to 1.15.0. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14842)
+- Updates blst to v3.14.0 and fixes the references in our deps.bzl file. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14921)
+- Updated tracing exporter from jaeger to otelhttp. This should not be a breaking change. Jaeger supports otel format, however you may need to update your URL as the default otel-collector port is 4318. See the [OpenTelemtry Protocol Exporter docs](https://opentelemetry.io/docs/specs/otel/protocol/exporter/) for more details. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14928)
+- Don't use MaxCover for Electra on-chain attestations. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14925)
+- Tracked validators cache: Remove validators from the cache if not seen after 1 hour. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14957)
+- execution requests errors on ssz length have been improved. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14962)
+- deprecate beacon api endpoints based on [3.0.0 release](https://github.com/ethereum/beacon-APIs/pull/506) for electra. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14967)
+- Use go-cmp for printing better diffs for assertions.DeepEqual. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14978)
+- Reorganized beacon chain flags in `--help` text into logical sections. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14959)
+- `--validators-registration-batch-size`: Change default value from `0` to `200`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14981)
+- Updated go to go1.24.0. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14969)
+- Updated gosec to v2.22.1 and golangci to v1.64.5. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14969)
+- Updated github.com/trailofbits/go-mutexasserts. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14969)
+- Updated rules_go to cf3c3af34bd869b864f5f2b98e2f41c2b220d6c9 to support go1.24.0. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14969)
+- Validate blob sidecar re-order signature and bad parent block. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15013)
+- Updated default gas limit from 30M to 36M. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14858)
+- Ignore errors from `hasSeenBit` and don't pack unaggregated attestations. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15018)
+
+### Removed
+
+- Remove Fulu state and block. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14905)
+- Removed the log summarizing all started services. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14958)
+
+### Fixed
+
+- fixed max and target blob per block from static to dynamic values. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14911)
+- refactored publish block and block ssz functions to fix gocognit. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14913)
+- refactored publish blinded block and blinded block ssz to correctly deal with version headers and sent blocks. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14913)
+- Only check for electra related engine methods if electra is active. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14924)
+- Fixed bug that breaks new blob storage layout code on Windows, caused by accidental use of platform-dependent path parsing package. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14931)
+- Fix E2E Process Deposit Evaluator for Electra. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14933)
+- Fixed the `bazel run //:gazelle` command in `DEPENDENCIES.md`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14934)
+- Fix E2E Deposit Activation Evaluator for Electra. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14938)
+- Dedicated processing of `SingleAttestation` in the monitor service. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14965)
+- adding in content type and accept headers for builder API call on registration. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14961)
+- fixed gocognit in block conversions between json and proto types. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14953)
+- Lint: Fix violations of S1009: should omit nil check; len() for nil slices is defined as zero. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14973)
+- Lint: Fix violations of non-constant format string in call. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14974)
+- Fixed violations of gosec G301. This is a check that created files and directories have file permissions 0750 and 0600 respectively. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14980)
+- Check for the correct attester slashing type during gossip validation. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14985)
+- cosmetic fix for post electra validator logs displaying attestation committee information correctly. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14992)
+- fix inserting the wrong committee index into the seen cache for electra attestations. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14998)
+- Allow any block type to be unmarshaled rather than only phase0 blocks in `slotByBlockRoot`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15008)
+- Fixed pruner to not block while pruning large database by introducing batchSize. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14929)
+- Decompose Electra block attestations to prevent redundant packing. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14896)
+- Fixed use of deprecated rand.Seed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14969)
+- Fixed build issue with SszGen where the go binary was not present in the $PATH. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14969)
+- fixed /eth/v1/config/spec displays BLOB_SIDECAR_SUBNET_COUNT,BLOB_SIDECAR_SUBNET_COUNT_ELECTRA. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15016)
+- Ensure that deleting a block from the database clears its entry in the slot->root db index. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15011)
+- Broadcasting BLS to execution changes should not use the request context in a go routine. Use context.Background() for the broadcasting go routine. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15019)
+- /eth/v1/validator/sync_committee_contribution should check for optimistic status and return a 503 if it's optimistic. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15022)
+- Fixes printing superfluous response.WriteHeader call from error in builder. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15025)
+- Fixes e2e run with builder having wrong gaslimit header due to not being set on eth1 nodes. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15025)
+- Fixed a bug in the event stream handler when processing payload attribute events where the timestamp and slot of the event would be based on the head rather than the current slot. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14963)
+- Handle unaggregated attestations when decomposing Electra block attestations. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15027)
+
 ## [v5.3.0](https://github.com/prysmaticlabs/prysm/compare/v5.2.0...v5.3.0) - 2025-02-12

 This release includes support for Pectra activation in the [Holesky](https://github.com/eth-clients/holesky) and [Sepolia](https://github.com/eth-clients/sepolia) testnets! The release contains many fixes for Electra that have been found in rigorous testing through devnets in the last few months.
@@ -3122,4 +3255,4 @@ There are no security updates in this release.

 # Older than v2.0.0

-For changelog history for releases older than v2.0.0, please refer to https://github.com/prysmaticlabs/prysm/releases
+For changelog history for releases older than v2.0.0, please refer to https://github.com/prysmaticlabs/prysm/releases
--- a/README.md
+++ b/README.md
@@ -1,5 +1,7 @@
-# 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)
 [![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)
@@ -7,31 +9,60 @@
 [![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)

-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/prysmaticlabs/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/prysmaticlabs)** 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/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 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)
--- a/48
+++ b/48
@@ -160,15 +160,15 @@ 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 = "b2038e2de2cace18f032249cb4bb0048abf583a36369fa98f687af1b3f880b26",
+    strip_prefix = "rules_go-cf3c3af34bd869b864f5f2b98e2f41c2b220d6c9",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.48.1/rules_go-v0.48.1.zip",
-        "https://github.com/bazelbuild/rules_go/releases/download/v0.48.1/rules_go-v0.48.1.zip",
+        "https://github.com/bazel-contrib/rules_go/archive/cf3c3af34bd869b864f5f2b98e2f41c2b220d6c9.tar.gz",
    ],
 )

@@ -210,7 +210,7 @@ load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_depe
 go_rules_dependencies()

 go_register_toolchains(
-    go_version = "1.23.5",
+    go_version = "1.24.0",
    nogo = "@//:nogo",
 )

@@ -255,7 +255,7 @@ filegroup(
    url = "https://github.com/ethereum/EIPs/archive/5480440fe51742ed23342b68cf106cefd427e39d.tar.gz",
 )

-consensus_spec_version = "v1.5.0-beta.2"
+consensus_spec_version = "v1.5.0-beta.4"

 bls_test_version = "v0.1.1"

@@ -271,7 +271,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    integrity = "sha256-X/bMxbKg1clo2aFEjBoeuFq/U+BF1eQopgRP/7nI3Qg=",
+    integrity = "sha256-QG0NUqaCvP5lKaKKwF/fmeICZVjONMlb7EE+MtYl0C0=",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/general.tar.gz" % consensus_spec_version,
 )

@@ -287,7 +287,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    integrity = "sha256-WSxdri5OJGuNApW+odKle5UzToDyEOx+F3lMiqamJAg=",
+    integrity = "sha256-8NQngTSSqzW/j3tOUi3r5h+94ChRbLNWTt7BOGqr4+E=",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/minimal.tar.gz" % consensus_spec_version,
 )

@@ -303,7 +303,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    integrity = "sha256-LYE8l3y/zSt4YVrehrJ3ralqtgeYNildiIp+HR6+xAI=",
+    integrity = "sha256-gFqxbaBnJ7dtdoj0zFbVrtlHv/bLNuWjrTHkyCAjFjI=",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/mainnet.tar.gz" % consensus_spec_version,
 )

@@ -318,7 +318,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    integrity = "sha256-jvZQ90qcJMTOqMsPO7sgeEVQmewZTHcz7LVDkNqwTFQ=",
+    integrity = "sha256-9paalF0POULpP2ga+4ouHSETKYrWNCUCZoJHPuFw06E=",
    strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
    url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )
@@ -365,9 +365,9 @@ filegroup(
    visibility = ["//visibility:public"],
 )
 """,
-    integrity = "sha256-b7ZTT+olF+VXEJYNTV5jggNtCkt9dOejm1i2VE+zy+0=",
-    strip_prefix = "holesky-874c199423ccd180607320c38cbaca05d9a1573a",
-    url = "https://github.com/eth-clients/holesky/archive/874c199423ccd180607320c38cbaca05d9a1573a.tar.gz",  # 2024-06-18
+    integrity = "sha256-YVFFrCmjoGZ3fXMWpsCpSsYbANy1grnqYwOLKIg2SsA=",
+    strip_prefix = "holesky-32a72e21c6e53c262f27d50dd540cb654517d03a",
+    url = "https://github.com/eth-clients/holesky/archive/32a72e21c6e53c262f27d50dd540cb654517d03a.tar.gz",  # 2025-03-17
 )

 http_archive(
@@ -381,9 +381,25 @@ filegroup(
    visibility = ["//visibility:public"],
 )
 """,
-    integrity = "sha256-cY/UgpCcYEhQf7JefD65FI8tn/A+rAvKhcm2/qiVdqY=",
-    strip_prefix = "sepolia-f2c219a93c4491cee3d90c18f2f8e82aed850eab",
-    url = "https://github.com/eth-clients/sepolia/archive/f2c219a93c4491cee3d90c18f2f8e82aed850eab.tar.gz",  # 2024-09-19
+    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(
@@ -431,7 +447,7 @@ 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")

--- a/api/BUILD.bazel
+++ b/api/BUILD.bazel
@@ -2,11 +2,7 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")

 go_library(
    name = "go_default_library",
-    srcs = [
-        "constants.go",
-        "headers.go",
-        "jwt.go",
-    ],
+    srcs = ["jwt.go"],
    importpath = "github.com/prysmaticlabs/prysm/v5/api",
    visibility = ["//visibility:public"],
    deps = [
--- a/api/client/BUILD.bazel
+++ b/api/client/BUILD.bazel
@@ -4,17 +4,29 @@ go_library(
    name = "go_default_library",
    srcs = [
        "client.go",
-        "errors.go",
+        "json_rest_handler.go",
        "options.go",
    ],
    importpath = "github.com/prysmaticlabs/prysm/v5/api/client",
    visibility = ["//visibility:public"],
-    deps = ["@com_github_pkg_errors//:go_default_library"],
+    deps = [
+        "//api/httputil:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
+    ],
 )

 go_test(
    name = "go_default_test",
-    srcs = ["client_test.go"],
+    srcs = [
+        "client_test.go",
+        "json_rest_handler_test.go",
+    ],
    embed = [":go_default_library"],
-    deps = ["//testing/require:go_default_library"],
+    deps = [
+        "//api/httputil:go_default_library",
+        "//api/server/structs:go_default_library",
+        "//testing/assert:go_default_library",
+        "//testing/require:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
+    ],
 )
--- a/api/client/Mock/BUILD.bazel
+++ b/api/client/Mock/BUILD.bazel
@@ -0,0 +1,9 @@
+load("@prysm//tools/go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["json_rest_handler_mock.go"],
+    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/Mock",
+    visibility = ["//visibility:public"],
+    deps = ["@org_uber_go_mock//gomock:go_default_library"],
+)
--- a/validator/client/beacon-api/mock/json_rest_handler_mock.go
+++ b/validator/client/beacon-api/mock/json_rest_handler_mock.go
@@ -7,7 +7,7 @@
 //

 // Package mock is a generated GoMock package.
-package mock
+package Mock

 import (
 	bytes "bytes"
--- a/api/client/beacon/BUILD.bazel
+++ b/api/client/beacon/BUILD.bazel
@@ -7,12 +7,14 @@ go_library(
        "doc.go",
        "health.go",
        "log.go",
+        "template.go",
    ],
    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/beacon",
    visibility = ["//visibility:public"],
    deps = [
        "//api/client:go_default_library",
        "//api/client/beacon/iface:go_default_library",
+        "//api/httputil:go_default_library",
        "//api/server:go_default_library",
        "//api/server/structs:go_default_library",
        "//consensus-types/primitives:go_default_library",
@@ -33,8 +35,8 @@ go_test(
    ],
    embed = [":go_default_library"],
    deps = [
-        "//api/client:go_default_library",
        "//api/client/beacon/testing:go_default_library",
+        "//api/httputil:go_default_library",
        "//testing/require:go_default_library",
        "@org_uber_go_mock//gomock:go_default_library",
    ],
--- a/api/client/beacon/client.go
+++ b/api/client/beacon/client.go
@@ -11,11 +11,11 @@ import (
 	"regexp"
 	"sort"
 	"strconv"
-	"text/template"

 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v5/api/client"
+	"github.com/prysmaticlabs/prysm/v5/api/httputil"
 	"github.com/prysmaticlabs/prysm/v5/api/server"
 	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
@@ -64,23 +64,6 @@ 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
-}
-
 // RenderGetBlockPath formats a block id into a path for the GetBlock API endpoint.
 func RenderGetBlockPath(id StateOrBlockId) string {
 	return path.Join(getSignedBlockPath, string(id))
@@ -114,8 +97,6 @@ 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
@@ -138,8 +119,6 @@ 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
@@ -206,7 +185,7 @@ var versionRE = regexp.MustCompile(`^(\w+)/(v\d+\.\d+\.\d+[-a-zA-Z0-9]*)\s*/?(.*
 func parseNodeVersion(v string) (*NodeVersion, error) {
 	groups := versionRE.FindStringSubmatch(v)
 	if len(groups) != 4 {
-		return nil, errors.Wrapf(client.ErrInvalidNodeVersion, "could not be parsed: %s", v)
+		return nil, errors.Wrapf(httputil.ErrInvalidNodeVersion, "could not be parsed: %s", v)
 	}
 	return &NodeVersion{
 		implementation: groups[1],
--- a/api/client/beacon/client_test.go
+++ b/api/client/beacon/client_test.go
@@ -4,7 +4,7 @@ import (
 	"net/url"
 	"testing"

-	"github.com/prysmaticlabs/prysm/v5/api/client"
+	"github.com/prysmaticlabs/prysm/v5/api/httputil"
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
 )

@@ -18,17 +18,17 @@ func TestParseNodeVersion(t *testing.T) {
 		{
 			name: "empty string",
 			v:    "",
-			err:  client.ErrInvalidNodeVersion,
+			err:  httputil.ErrInvalidNodeVersion,
 		},
 		{
 			name: "Prysm as the version string",
 			v:    "Prysm",
-			err:  client.ErrInvalidNodeVersion,
+			err:  httputil.ErrInvalidNodeVersion,
 		},
 		{
 			name: "semver only",
 			v:    "v2.0.6",
-			err:  client.ErrInvalidNodeVersion,
+			err:  httputil.ErrInvalidNodeVersion,
 		},
 		{
 			name: "complete version",
@@ -92,7 +92,7 @@ func TestValidHostname(t *testing.T) {
 		{
 			name:    "hostname without port",
 			hostArg: "mydomain.org",
-			err:     client.ErrMalformedHostname,
+			err:     httputil.ErrMalformedHostname,
 		},
 		{
 			name:    "hostname with port",
--- a/api/client/beacon/template.go
+++ b/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)
+}
--- a/api/client/builder/BUILD.bazel
+++ b/api/client/builder/BUILD.bazel
@@ -11,8 +11,7 @@ go_library(
    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/builder",
    visibility = ["//visibility:public"],
    deps = [
-        "//api:go_default_library",
-        "//api/client:go_default_library",
+        "//api/httputil:go_default_library",
        "//api/server:go_default_library",
        "//api/server/structs:go_default_library",
        "//config/fieldparams:go_default_library",
@@ -47,7 +46,7 @@ go_test(
    data = glob(["testdata/**"]),
    embed = [":go_default_library"],
    deps = [
-        "//api:go_default_library",
+        "//api/httputil:go_default_library",
        "//api/server/structs:go_default_library",
        "//config/fieldparams:go_default_library",
        "//config/params:go_default_library",
--- a/api/client/builder/client.go
+++ b/api/client/builder/client.go
@@ -13,9 +13,9 @@ import (
 	"text/template"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api"
-	"github.com/prysmaticlabs/prysm/v5/api/client"
+	"github.com/prysmaticlabs/prysm/v5/api/httputil"
 	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
+	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
@@ -35,9 +35,14 @@ 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)
@@ -52,6 +57,12 @@ 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) {
@@ -95,9 +106,10 @@ 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).
@@ -139,7 +151,7 @@ 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)
@@ -155,10 +167,6 @@ func (c *Client) do(ctx context.Context, method string, path string, body io.Rea
 	if err != nil {
 		return
 	}
-	if method == http.MethodPost {
-		req.Header.Set("Content-Type", api.JsonMediaType)
-	}
-	req.Header.Set("Accept", api.JsonMediaType)
 	req.Header.Add("User-Agent", version.BuildData())
 	for _, o := range opts {
 		o(req)
@@ -182,11 +190,12 @@ func (c *Client) do(ctx context.Context, method string, path string, body io.Rea
 		err = non200Err(r)
 		return
 	}
-	res, err = io.ReadAll(io.LimitReader(r.Body, client.MaxBodySize))
+	res, err = io.ReadAll(io.LimitReader(r.Body, httputil.MaxBodySize))
 	if err != nil {
 		err = errors.Wrap(err, "error reading http response body from builder server")
 		return
 	}
+	header = r.Header
 	return
 }

@@ -216,64 +225,145 @@ 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)
-	if err != nil {
-		return nil, err
+	var getOpts reqOption
+	if c.sszEnabled {
+		getOpts = func(r *http.Request) {
+			r.Header.Set("Accept", httputil.OctetStreamMediaType)
+		}
+	} else {
+		getOpts = func(r *http.Request) {
+			r.Header.Set("Accept", httputil.JsonMediaType)
+		}
 	}
-	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)
+	data, header, err := c.do(ctx, http.MethodGet, path, nil, getOpts)
+	if err != nil {
+		return nil, errors.Wrap(err, "error getting header from builder server")
 	}

-	ver, err := version.FromString(strings.ToLower(v.Version))
+	bid, err := c.parseHeaderResponse(data, header)
 	if err != nil {
-		return nil, errors.Wrap(err, fmt.Sprintf("unsupported header version %s", strings.ToLower(v.Version)))
+		return nil, errors.Wrapf(
+			err,
+			"error rendering exec header template with 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(httputil.VersionHeader) != "" {
+		versionHeader = header.Get(httputil.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",
+			)
+		}
+		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 {
-		hr := &ExecHeaderResponseElectra{}
-		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 WrappedSignedBuilderBidElectra(p)
+		return c.parseHeaderElectra(data)
 	}
 	if ver >= 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)
-		}
-		p, err := hr.ToProto()
-		if err != nil {
-			return nil, errors.Wrapf(err, "could not extract proto message from header")
-		}
-		return WrappedSignedBuilderBidDeneb(p)
+		return c.parseHeaderDeneb(data)
 	}
 	if ver >= 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)
+		return c.parseHeaderCapella(data)
 	}
 	if ver >= 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)
+		return c.parseHeaderBellatrix(data)
 	}
-	return nil, fmt.Errorf("unsupported header version %s", strings.ToLower(v.Version))
+
+	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
@@ -288,70 +378,243 @@ func (c *Client) RegisterValidator(ctx context.Context, svr []*ethpb.SignedValid
 		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", httputil.OctetStreamMediaType)
+			r.Header.Set("Accept", httputil.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", httputil.JsonMediaType)
+			r.Header.Set("Accept", httputil.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
 	}
-
-	_, err = c.do(ctx, http.MethodPost, postRegisterValidatorPath, bytes.NewBuffer(body))
-	if err != nil {
-		return err
-	}
-	log.WithField("registrationCount", len(svr)).Debug("Successfully registered validator(s) on builder")
-	return nil
+	return body, nil
 }

-var errResponseVersionMismatch = errors.New("builder API response uses a different version than requested in " + api.VersionHeader + " header")
+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 " + httputil.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(httputil.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
 	}

-	// massage the proto struct type data into the api response type.
+	if c.sszEnabled {
+		body, err := sb.MarshalSSZ()
+		if err != nil {
+			return nil, nil, errors.Wrap(err, "could not marshal SSZ for blinded block")
+		}
+		opt := func(r *http.Request) {
+			r.Header.Set(httputil.VersionHeader, version.String(sb.Version()))
+			r.Header.Set("Content-Type", httputil.OctetStreamMediaType)
+			r.Header.Set("Accept", httputil.OctetStreamMediaType)
+		}
+		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 post request to json")
+		return nil, nil, errors.Wrap(err, "error marshaling blinded block to JSON")
 	}
-	postOpts := func(r *http.Request) {
-		r.Header.Add("Eth-Consensus-Version", version.String(sb.Version()))
-		r.Header.Set("Content-Type", api.JsonMediaType)
-		r.Header.Set("Accept", api.JsonMediaType)
+	opt := func(r *http.Request) {
+		r.Header.Set(httputil.VersionHeader, version.String(sb.Version()))
+		r.Header.Set("Content-Type", httputil.JsonMediaType)
+		r.Header.Set("Accept", httputil.JsonMediaType)
 	}
-	// post the blinded block - the execution payload response should contain the unblinded payload, along with the
-	// blobs bundle if it is post deneb.
-	rb, 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")
+	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)
 	}
-	// ExecutionPayloadResponse parses just the outer container and the Value key, enabling it to use the .Value
-	// key to determine which underlying data type to use to finish the unmarshaling.
+	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(rb, ep); err != nil {
-		return nil, nil, errors.Wrap(err, "error unmarshaling the builder ExecutionPayloadResponse")
+	if err := json.Unmarshal(respBytes, ep); err != nil {
+		return nil, nil, errors.Wrap(err, "error unmarshaling ExecutionPayloadResponse")
 	}
-	if strings.ToLower(ep.Version) != version.String(sb.Version()) {
-		return nil, nil, errors.Wrapf(errResponseVersionMismatch, "req=%s, recv=%s", strings.ToLower(ep.Version), version.String(sb.Version()))
-	}
-	// This parses the rest of the response and returns the inner data field.
 	pp, err := ep.ParsePayload()
 	if err != nil {
-		return nil, nil, errors.Wrapf(err, "failed to parse execution payload from builder with version=%s", ep.Version)
+		return nil, nil, errors.Wrapf(err, "failed to parse payload with version=%s", ep.Version)
 	}
-	// Get the payload as a proto.Message so it can be wrapped as an execution payload interface.
 	pb, err := pp.PayloadProto()
 	if err != nil {
 		return nil, nil, err
@@ -360,11 +623,13 @@ func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlyS
 	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 builder response with version=%s", ep.Version)
+			return nil, nil, errors.Wrapf(err, "failed to extract blobs bundle from version=%s", ep.Version)
 		}
 		return ed, bbpb, nil
 	}
@@ -375,12 +640,15 @@ func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlyS
 // 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", httputil.JsonMediaType)
+	}
+	_, _, err := c.do(ctx, http.MethodGet, getStatus, nil, getOpts)
 	return err
 }

 func non200Err(response *http.Response) error {
-	bodyBytes, err := io.ReadAll(io.LimitReader(response.Body, client.MaxErrBodySize))
+	bodyBytes, err := io.ReadAll(io.LimitReader(response.Body, httputil.MaxErrBodySize))
 	var errMessage ErrorMessage
 	var body string
 	if err != nil {
@@ -390,6 +658,18 @@ 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
--- a/api/client/builder/client_test.go
+++ b/api/client/builder/client_test.go
@@ -8,11 +8,10 @@ import (
 	"io"
 	"net/http"
 	"net/url"
-	"strconv"
 	"testing"

 	"github.com/prysmaticlabs/go-bitfield"
-	"github.com/prysmaticlabs/prysm/v5/api"
+	"github.com/prysmaticlabs/prysm/v5/api/httputil"
 	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
@@ -88,39 +87,84 @@ 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) {
-			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("JSON success", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, httputil.JsonMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, httputil.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, httputil.OctetStreamMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, httputil.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) {
@@ -176,6 +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, httputil.JsonMediaType, r.Header.Get("Accept"))
 				return &http.Response{
 					StatusCode: http.StatusOK,
 					Body:       io.NopCloser(bytes.NewBufferString(testExampleHeaderResponse)),
@@ -207,9 +252,56 @@ func TestClient_GetHeader(t *testing.T) {
 		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, httputil.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(httputil.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, httputil.JsonMediaType, r.Header.Get("Accept"))
 				require.Equal(t, expectedPath, r.URL.Path)
 				return &http.Response{
 					StatusCode: http.StatusOK,
@@ -238,9 +330,52 @@ func TestClient_GetHeader(t *testing.T) {
 		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, httputil.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(httputil.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, httputil.JsonMediaType, r.Header.Get("Accept"))
 				require.Equal(t, expectedPath, r.URL.Path)
 				return &http.Response{
 					StatusCode: http.StatusOK,
@@ -277,6 +412,56 @@ func TestClient_GetHeader(t *testing.T) {
 			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, httputil.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(httputil.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)
+		}
+	})
 	t.Run("deneb, too many kzg commitments", func(t *testing.T) {
 		hc := &http.Client{
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
@@ -293,11 +478,12 @@ 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, httputil.JsonMediaType, r.Header.Get("Accept"))
 				require.Equal(t, expectedPath, r.URL.Path)
 				return &http.Response{
 					StatusCode: http.StatusOK,
@@ -338,6 +524,61 @@ func TestClient_GetHeader(t *testing.T) {
 		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, httputil.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(httputil.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{
@@ -367,8 +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, api.JsonMediaType, r.Header.Get("Content-Type"))
-				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
+				require.Equal(t, httputil.JsonMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, httputil.JsonMediaType, r.Header.Get("Accept"))
 				return &http.Response{
 					StatusCode: http.StatusOK,
 					Body:       io.NopCloser(bytes.NewBufferString(testExampleExecutionPayload)),
@@ -390,13 +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(httputil.VersionHeader))
+				require.Equal(t, httputil.OctetStreamMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, httputil.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(httputil.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, api.JsonMediaType, r.Header.Get("Content-Type"))
-				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
+				require.Equal(t, "capella", r.Header.Get(httputil.VersionHeader))
+				require.Equal(t, httputil.JsonMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, httputil.JsonMediaType, r.Header.Get("Accept"))
 				return &http.Response{
 					StatusCode: http.StatusOK,
 					Body:       io.NopCloser(bytes.NewBufferString(testExampleExecutionPayloadCapella)),
@@ -420,14 +701,56 @@ func TestSubmitBlindedBlock(t *testing.T) {
 		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(httputil.VersionHeader))
+				require.Equal(t, httputil.OctetStreamMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, httputil.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(httputil.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)
+	})
 	t.Run("deneb", 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("Eth-Consensus-Version"))
-				require.Equal(t, api.JsonMediaType, r.Header.Get("Content-Type"))
-				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
+				require.Equal(t, "deneb", r.Header.Get(httputil.VersionHeader))
+				require.Equal(t, httputil.JsonMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, httputil.JsonMediaType, r.Header.Get("Accept"))
 				var req structs.SignedBlindedBeaconBlockDeneb
 				err := json.NewDecoder(r.Body).Decode(&req)
 				require.NoError(t, err)
@@ -460,6 +783,140 @@ func TestSubmitBlindedBlock(t *testing.T) {
 		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(httputil.VersionHeader))
+				require.Equal(t, httputil.OctetStreamMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, httputil.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(httputil.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(httputil.VersionHeader))
+				require.Equal(t, httputil.JsonMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, httputil.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(httputil.VersionHeader))
+				require.Equal(t, httputil.OctetStreamMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, httputil.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(httputil.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)
+	})
 	t.Run("mismatched versions, expected bellatrix got capella", func(t *testing.T) {
 		hc := &http.Client{
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
@@ -586,7 +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"),
@@ -605,8 +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"),
@@ -620,7 +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"),
 				},
@@ -728,7 +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"),
@@ -747,8 +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"),
@@ -762,7 +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"),
@@ -875,7 +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"),
@@ -922,6 +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)
--- a/api/client/builder/errors.go
+++ b/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")
--- a/api/client/client.go
+++ b/api/client/client.go
@@ -8,12 +8,7 @@ import (
 	"net/url"

 	"github.com/pkg/errors"
-)
-
-const (
-	MaxBodySize      int64 = 1 << 23 // 8MB default, WithMaxBodySize can override
-	MaxBodySizeState int64 = 1 << 29 // 512MB
-	MaxErrBodySize   int64 = 1 << 17 // 128KB
+	"github.com/prysmaticlabs/prysm/v5/api/httputil"
 )

 // Client is a wrapper object around the HTTP client.
@@ -35,7 +30,7 @@ func NewClient(host string, opts ...ClientOpt) (*Client, error) {
 	c := &Client{
 		hc:          &http.Client{},
 		baseURL:     u,
-		maxBodySize: MaxBodySize,
+		maxBodySize: httputil.MaxBodySize,
 	}
 	for _, o := range opts {
 		o(c)
@@ -67,7 +62,7 @@ func urlForHost(h string) (*url.URL, error) {
 	// try to parse as host:port
 	host, port, err := net.SplitHostPort(h)
 	if err != nil {
-		return nil, ErrMalformedHostname
+		return nil, httputil.ErrMalformedHostname
 	}
 	return &url.URL{Host: net.JoinHostPort(host, port), Scheme: "http"}, nil
 }
@@ -95,7 +90,7 @@ func (c *Client) Get(ctx context.Context, path string, opts ...ReqOption) ([]byt
 		err = r.Body.Close()
 	}()
 	if r.StatusCode != http.StatusOK {
-		return nil, Non200Err(r)
+		return nil, httputil.Non200Err(r)
 	}
 	b, err := io.ReadAll(io.LimitReader(r.Body, c.maxBodySize))
 	if err != nil {
--- a/api/client/client_test.go
+++ b/api/client/client_test.go
@@ -4,6 +4,7 @@ import (
 	"net/url"
 	"testing"

+	"github.com/prysmaticlabs/prysm/v5/api/httputil"
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
 )

@@ -18,7 +19,7 @@ func TestValidHostname(t *testing.T) {
 		{
 			name:    "hostname without port",
 			hostArg: "mydomain.org",
-			err:     ErrMalformedHostname,
+			err:     httputil.ErrMalformedHostname,
 		},
 	}
 	for _, c := range cases {
--- a/api/client/event/BUILD.bazel
+++ b/api/client/event/BUILD.bazel
@@ -9,8 +9,7 @@ go_library(
    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/event",
    visibility = ["//visibility:public"],
    deps = [
-        "//api:go_default_library",
-        "//api/client:go_default_library",
+        "//api/httputil:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
    ],
--- a/api/client/event/event_stream.go
+++ b/api/client/event/event_stream.go
@@ -8,8 +8,7 @@ import (
 	"strings"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api"
-	"github.com/prysmaticlabs/prysm/v5/api/client"
+	"github.com/prysmaticlabs/prysm/v5/api/httputil"
 	log "github.com/sirupsen/logrus"
 )

@@ -85,13 +84,13 @@ func (h *EventStream) Subscribe(eventsChannel chan<- *Event) {
 			Data:      []byte(errors.Wrap(err, "failed to create HTTP request").Error()),
 		}
 	}
-	req.Header.Set("Accept", api.EventStreamMediaType)
-	req.Header.Set("Connection", api.KeepAlive)
+	req.Header.Set("Accept", httputil.EventStreamMediaType)
+	req.Header.Set("Connection", httputil.KeepAlive)
 	resp, err := h.httpClient.Do(req)
 	if err != nil {
 		eventsChannel <- &Event{
 			EventType: EventConnectionError,
-			Data:      []byte(errors.Wrap(err, client.ErrConnectionIssue.Error()).Error()),
+			Data:      []byte(errors.Wrap(err, httputil.ErrConnectionIssue.Error()).Error()),
 		}
 		return
 	}
@@ -145,7 +144,7 @@ func (h *EventStream) Subscribe(eventsChannel chan<- *Event) {
 	if err := scanner.Err(); err != nil {
 		eventsChannel <- &Event{
 			EventType: EventConnectionError,
-			Data:      []byte(errors.Wrap(err, errors.Wrap(client.ErrConnectionIssue, "scanner failed").Error()).Error()),
+			Data:      []byte(errors.Wrap(err, errors.Wrap(httputil.ErrConnectionIssue, "scanner failed").Error()).Error()),
 		}
 	}
 }
--- a/validator/client/beacon-api/json_rest_handler.go
+++ b/validator/client/beacon-api/json_rest_handler.go
@@ -1,4 +1,4 @@
-package beacon_api
+package client

 import (
 	"bytes"
@@ -9,8 +9,7 @@ import (
 	"strings"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api"
-	"github.com/prysmaticlabs/prysm/v5/network/httputil"
+	"github.com/prysmaticlabs/prysm/v5/api/httputil"
 )

 type JsonRestHandler interface {
@@ -88,7 +87,7 @@ func (c *BeaconApiJsonRestHandler) Post(
 	for headerKey, headerValue := range headers {
 		req.Header.Set(headerKey, headerValue)
 	}
-	req.Header.Set("Content-Type", api.JsonMediaType)
+	req.Header.Set("Content-Type", httputil.JsonMediaType)

 	httpResp, err := c.client.Do(req)
 	if err != nil {
@@ -109,7 +108,7 @@ func decodeResp(httpResp *http.Response, resp interface{}) error {
 		return errors.Wrapf(err, "failed to read response body for %s", httpResp.Request.URL)
 	}

-	if !strings.Contains(httpResp.Header.Get("Content-Type"), api.JsonMediaType) {
+	if !strings.Contains(httpResp.Header.Get("Content-Type"), httputil.JsonMediaType) {
 		// 2XX codes are a success
 		if strings.HasPrefix(httpResp.Status, "2") {
 			return nil
--- a/validator/client/beacon-api/json_rest_handler_test.go
+++ b/validator/client/beacon-api/json_rest_handler_test.go
@@ -1,4 +1,4 @@
-package beacon_api
+package client

 import (
 	"bytes"
@@ -11,9 +11,8 @@ import (
 	"time"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api"
+	"github.com/prysmaticlabs/prysm/v5/api/httputil"
 	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
-	"github.com/prysmaticlabs/prysm/v5/network/httputil"
 	"github.com/prysmaticlabs/prysm/v5/testing/assert"
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
 )
@@ -33,7 +32,7 @@ func TestGet(t *testing.T) {
 		marshalledJson, err := json.Marshal(genesisJson)
 		require.NoError(t, err)

-		w.Header().Set("Content-Type", api.JsonMediaType)
+		w.Header().Set("Content-Type", httputil.JsonMediaType)
 		_, err = w.Write(marshalledJson)
 		require.NoError(t, err)
 	})
@@ -67,7 +66,7 @@ func TestPost(t *testing.T) {
 	mux.HandleFunc(endpoint, func(w http.ResponseWriter, r *http.Request) {
 		// Make sure the request headers have been set
 		assert.Equal(t, "bar", r.Header.Get("foo"))
-		assert.Equal(t, api.JsonMediaType, r.Header.Get("Content-Type"))
+		assert.Equal(t, httputil.JsonMediaType, r.Header.Get("Content-Type"))

 		// Make sure the data matches
 		receivedBytes := make([]byte, len(dataBytes))
@@ -79,7 +78,7 @@ func TestPost(t *testing.T) {
 		marshalledJson, err := json.Marshal(genesisJson)
 		require.NoError(t, err)

-		w.Header().Set("Content-Type", api.JsonMediaType)
+		w.Header().Set("Content-Type", httputil.JsonMediaType)
 		_, err = w.Write(marshalledJson)
 		require.NoError(t, err)
 	})
@@ -115,7 +114,7 @@ func Test_decodeResp(t *testing.T) {
 			Status:     "200",
 			StatusCode: http.StatusOK,
 			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.OctetStreamMediaType}},
+			Header:     map[string][]string{"Content-Type": {httputil.OctetStreamMediaType}},
 		}
 		require.NoError(t, decodeResp(r, nil))
 	})
@@ -125,7 +124,7 @@ func Test_decodeResp(t *testing.T) {
 			Status:     "204",
 			StatusCode: http.StatusNoContent,
 			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.OctetStreamMediaType}},
+			Header:     map[string][]string{"Content-Type": {httputil.OctetStreamMediaType}},
 		}
 		require.NoError(t, decodeResp(r, nil))
 	})
@@ -137,7 +136,7 @@ func Test_decodeResp(t *testing.T) {
 			Status:     "500",
 			StatusCode: http.StatusInternalServerError,
 			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.OctetStreamMediaType}},
+			Header:     map[string][]string{"Content-Type": {httputil.OctetStreamMediaType}},
 		}
 		err = decodeResp(r, nil)
 		errJson := &httputil.DefaultJsonError{}
@@ -154,7 +153,7 @@ func Test_decodeResp(t *testing.T) {
 			Status:     "200",
 			StatusCode: http.StatusOK,
 			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
+			Header:     map[string][]string{"Content-Type": {httputil.JsonMediaType}},
 		}
 		resp := &j{}
 		require.NoError(t, decodeResp(r, resp))
@@ -166,7 +165,7 @@ func Test_decodeResp(t *testing.T) {
 			Status:     "200",
 			StatusCode: http.StatusOK,
 			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
+			Header:     map[string][]string{"Content-Type": {httputil.JsonMediaType}},
 		}
 		require.NoError(t, decodeResp(r, nil))
 	})
@@ -176,7 +175,7 @@ func Test_decodeResp(t *testing.T) {
 			Status:     "204",
 			StatusCode: http.StatusNoContent,
 			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
+			Header:     map[string][]string{"Content-Type": {httputil.JsonMediaType}},
 		}
 		require.NoError(t, decodeResp(r, nil))
 	})
@@ -189,7 +188,7 @@ func Test_decodeResp(t *testing.T) {
 			Status:     "500",
 			StatusCode: http.StatusInternalServerError,
 			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
+			Header:     map[string][]string{"Content-Type": {httputil.JsonMediaType}},
 		}
 		err = decodeResp(r, nil)
 		errJson := &httputil.DefaultJsonError{}
@@ -205,7 +204,7 @@ func Test_decodeResp(t *testing.T) {
 			Status:     "200",
 			StatusCode: http.StatusOK,
 			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
+			Header:     map[string][]string{"Content-Type": {httputil.JsonMediaType}},
 			Request:    &http.Request{},
 		}
 		resp := &j{}
@@ -220,7 +219,7 @@ func Test_decodeResp(t *testing.T) {
 			Status:     "500",
 			StatusCode: http.StatusInternalServerError,
 			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
+			Header:     map[string][]string{"Content-Type": {httputil.JsonMediaType}},
 			Request:    &http.Request{},
 		}
 		err = decodeResp(r, nil)
--- a/api/grpcutil/BUILD.bazel
+++ b/api/grpcutil/BUILD.bazel
@@ -3,10 +3,10 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
    name = "go_default_library",
    srcs = [
-        "grpcutils.go",
+        "common.go",
        "parameters.go",
    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/grpc",
+    importpath = "github.com/prysmaticlabs/prysm/v5/api/grpcutil",
    visibility = ["//visibility:public"],
    deps = [
        "@com_github_sirupsen_logrus//:go_default_library",
@@ -17,7 +17,7 @@ go_library(

 go_test(
    name = "go_default_test",
-    srcs = ["grpcutils_test.go"],
+    srcs = ["common_test.go"],
    embed = [":go_default_library"],
    deps = [
        "//testing/assert:go_default_library",
--- a/api/grpcutil/common.go
+++ b/api/grpcutil/common.go
@@ -1,4 +1,4 @@
-package grpc
+package grpcutil

 import (
 	"context"
--- a/api/grpcutil/common_test.go
+++ b/api/grpcutil/common_test.go
@@ -1,4 +1,4 @@
-package grpc
+package grpcutil

 import (
 	"context"
--- a/api/grpcutil/parameters.go
+++ b/api/grpcutil/parameters.go
@@ -1,4 +1,4 @@
-package grpc
+package grpcutil

 // CustomErrorMetadataKey is the name of the metadata key storing additional error information.
 // Metadata value is expected to be a byte-encoded JSON object.
--- a/network/httputil/BUILD.bazel
+++ b/network/httputil/BUILD.bazel
@@ -3,24 +3,31 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
    name = "go_default_library",
    srcs = [
+        "common.go",
+        "constants.go",
        "errors.go",
+        "headers.go",
        "reader.go",
        "writer.go",
    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/network/httputil",
+    importpath = "github.com/prysmaticlabs/prysm/v5/api/httputil",
    visibility = ["//visibility:public"],
    deps = [
-        "//api:go_default_library",
+        "//consensus-types/primitives:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
    ],
 )

 go_test(
    name = "go_default_test",
-    srcs = ["reader_test.go"],
+    srcs = [
+        "common_test.go",
+        "reader_test.go",
+    ],
    embed = [":go_default_library"],
    deps = [
-        "//api:go_default_library",
+        "//consensus-types/primitives:go_default_library",
        "//testing/assert:go_default_library",
        "//testing/require:go_default_library",
    ],
--- a/api/httputil/common.go
+++ b/api/httputil/common.go
@@ -0,0 +1,23 @@
+package httputil
+
+import (
+	"fmt"
+	neturl "net/url"
+	"strconv"
+
+	"github.com/prysmaticlabs/prysm/v5/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())
+}
--- a/api/httputil/common_test.go
+++ b/api/httputil/common_test.go
@@ -0,0 +1,37 @@
+package httputil
+
+import (
+	"net/url"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v5/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)
+}
--- a/api/httputil/constants.go
+++ b/api/httputil/constants.go
@@ -1,4 +1,4 @@
-package api
+package httputil

 const (
 	WebUrlPrefix        = "/v2/validator/"
@@ -7,3 +7,9 @@ const (
 	SystemLogsPrefix    = "health/logs"
 	AuthTokenFileName   = "auth-token"
 )
+
+const (
+	MaxBodySize      int64 = 1 << 23 // 8MB default, WithMaxBodySize can override
+	MaxBodySizeState int64 = 1 << 29 // 512MB
+	MaxErrBodySize   int64 = 1 << 17 // 128KB
+)
--- a/api/httputil/errors.go
+++ b/api/httputil/errors.go
@@ -1,4 +1,4 @@
-package client
+package httputil

 import (
 	"fmt"
@@ -8,6 +8,14 @@ import (
 	"github.com/pkg/errors"
 )

+func HandleError(w http.ResponseWriter, message string, code int) {
+	errJson := &DefaultJsonError{
+		Message: message,
+		Code:    code,
+	}
+	WriteError(w, errJson)
+}
+
 // ErrMalformedHostname is used to indicate if a host name's format is incorrect.
 var ErrMalformedHostname = errors.New("hostname must include port, separated by one colon, like example.com:3500")

@@ -24,6 +32,9 @@ var ErrInvalidNodeVersion = errors.New("invalid node version response")
 // ErrConnectionIssue represents a connection problem.
 var ErrConnectionIssue = errors.New("could not connect")

+// ErrNotSupported represents a connection to a beacon node that is non prysm or wrong version
+var ErrNotSupported = errors.New("endpoint not supported")
+
 // Non200Err is a function that parses an HTTP response to handle responses that are not 200 with a formatted error.
 func Non200Err(r *http.Response) error {
 	b, err := io.ReadAll(io.LimitReader(r.Body, MaxErrBodySize))
--- a/api/httputil/headers.go
+++ b/api/httputil/headers.go
@@ -1,4 +1,4 @@
-package api
+package httputil

 import "net/http"

--- a/network/httputil/reader.go
+++ b/network/httputil/reader.go
@@ -5,8 +5,6 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
-
-	"github.com/prysmaticlabs/prysm/v5/api"
 )

 // match a number with optional decimals
@@ -23,7 +21,7 @@ func RespondWithSsz(req *http.Request) bool {
 	for _, t := range types {
 		values := strings.Split(t, ";")
 		name := values[0]
-		if name != api.JsonMediaType && name != api.OctetStreamMediaType {
+		if name != JsonMediaType && name != OctetStreamMediaType {
 			continue
 		}
 		// no params specified
@@ -49,10 +47,10 @@ func RespondWithSsz(req *http.Request) bool {
 		}
 	}

-	return currentType == api.OctetStreamMediaType
+	return currentType == OctetStreamMediaType
 }

 // IsRequestSsz checks if the request object should be interpreted as ssz
 func IsRequestSsz(req *http.Request) bool {
-	return req.Header.Get("Content-Type") == api.OctetStreamMediaType
+	return req.Header.Get("Content-Type") == OctetStreamMediaType
 }
--- a/network/httputil/reader_test.go
+++ b/network/httputil/reader_test.go
@@ -7,7 +7,6 @@ import (
 	"net/http/httptest"
 	"testing"

-	"github.com/prysmaticlabs/prysm/v5/api"
 	"github.com/prysmaticlabs/prysm/v5/testing/assert"
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
 )
@@ -15,42 +14,42 @@ import (
 func TestRespondWithSsz(t *testing.T) {
 	t.Run("ssz_requested", func(t *testing.T) {
 		request := httptest.NewRequest(http.MethodGet, "http://foo.example", nil)
-		request.Header["Accept"] = []string{api.OctetStreamMediaType}
+		request.Header["Accept"] = []string{OctetStreamMediaType}
 		result := RespondWithSsz(request)
 		assert.Equal(t, true, result)
 	})

 	t.Run("ssz_content_type_first", func(t *testing.T) {
 		request := httptest.NewRequest("GET", "http://foo.example", nil)
-		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s", api.OctetStreamMediaType, api.JsonMediaType)}
+		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s", OctetStreamMediaType, JsonMediaType)}
 		result := RespondWithSsz(request)
 		assert.Equal(t, true, result)
 	})

 	t.Run("ssz_content_type_preferred_1", func(t *testing.T) {
 		request := httptest.NewRequest(http.MethodGet, "http://foo.example", nil)
-		request.Header["Accept"] = []string{fmt.Sprintf("%s;q=0.9,%s", api.JsonMediaType, api.OctetStreamMediaType)}
+		request.Header["Accept"] = []string{fmt.Sprintf("%s;q=0.9,%s", JsonMediaType, OctetStreamMediaType)}
 		result := RespondWithSsz(request)
 		assert.Equal(t, true, result)
 	})

 	t.Run("ssz_content_type_preferred_2", func(t *testing.T) {
 		request := httptest.NewRequest(http.MethodGet, "http://foo.example", nil)
-		request.Header["Accept"] = []string{fmt.Sprintf("%s;q=0.95,%s;q=0.9", api.OctetStreamMediaType, api.JsonMediaType)}
+		request.Header["Accept"] = []string{fmt.Sprintf("%s;q=0.95,%s;q=0.9", OctetStreamMediaType, JsonMediaType)}
 		result := RespondWithSsz(request)
 		assert.Equal(t, true, result)
 	})

 	t.Run("other_content_type_preferred", func(t *testing.T) {
 		request := httptest.NewRequest("GET", "http://foo.example", nil)
-		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s;q=0.9", api.JsonMediaType, api.OctetStreamMediaType)}
+		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s;q=0.9", JsonMediaType, OctetStreamMediaType)}
 		result := RespondWithSsz(request)
 		assert.Equal(t, false, result)
 	})

 	t.Run("other_params", func(t *testing.T) {
 		request := httptest.NewRequest(http.MethodGet, "http://foo.example", nil)
-		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s;q=0.9,otherparam=xyz", api.JsonMediaType, api.OctetStreamMediaType)}
+		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s;q=0.9,otherparam=xyz", JsonMediaType, OctetStreamMediaType)}
 		result := RespondWithSsz(request)
 		assert.Equal(t, false, result)
 	})
@@ -96,7 +95,7 @@ func TestIsRequestSsz(t *testing.T) {
 		_, err := body.WriteString("something")
 		require.NoError(t, err)
 		request := httptest.NewRequest(http.MethodPost, "http://foo.example", &body)
-		request.Header["Content-Type"] = []string{api.OctetStreamMediaType}
+		request.Header["Content-Type"] = []string{OctetStreamMediaType}
 		result := IsRequestSsz(request)
 		assert.Equal(t, true, result)
 	})
@@ -116,7 +115,7 @@ func TestIsRequestSsz(t *testing.T) {

 	t.Run("ssz Post json content type", func(t *testing.T) {
 		request := httptest.NewRequest(http.MethodPost, "http://foo.example", nil)
-		request.Header["Content-Type"] = []string{api.JsonMediaType}
+		request.Header["Content-Type"] = []string{JsonMediaType}
 		result := IsRequestSsz(request)
 		assert.Equal(t, false, result)
 	})
--- a/network/httputil/writer.go
+++ b/network/httputil/writer.go
@@ -8,7 +8,6 @@ import (
 	"net/http"
 	"strconv"

-	"github.com/prysmaticlabs/prysm/v5/api"
 	log "github.com/sirupsen/logrus"
 )

@@ -32,7 +31,7 @@ func (e *DefaultJsonError) Error() string {

 // WriteJson writes the response message in JSON format.
 func WriteJson(w http.ResponseWriter, v any) {
-	w.Header().Set("Content-Type", api.JsonMediaType)
+	w.Header().Set("Content-Type", JsonMediaType)
 	w.WriteHeader(http.StatusOK)
 	if err := json.NewEncoder(w).Encode(v); err != nil {
 		log.WithError(err).Error("Could not write response message")
@@ -40,10 +39,9 @@ func WriteJson(w http.ResponseWriter, v any) {
 }

 // WriteSsz writes the response message in ssz format
-func WriteSsz(w http.ResponseWriter, respSsz []byte, fileName string) {
+func WriteSsz(w http.ResponseWriter, respSsz []byte) {
 	w.Header().Set("Content-Length", strconv.Itoa(len(respSsz)))
-	w.Header().Set("Content-Type", api.OctetStreamMediaType)
-	w.Header().Set("Content-Disposition", "attachment; filename="+fileName)
+	w.Header().Set("Content-Type", OctetStreamMediaType)
 	if _, err := io.Copy(w, io.NopCloser(bytes.NewReader(respSsz))); err != nil {
 		log.WithError(err).Error("could not write response message")
 	}
@@ -57,7 +55,7 @@ func WriteError(w http.ResponseWriter, errJson HasStatusCode) {
 		return
 	}
 	w.Header().Set("Content-Length", strconv.Itoa(len(j)))
-	w.Header().Set("Content-Type", api.JsonMediaType)
+	w.Header().Set("Content-Type", JsonMediaType)
 	w.WriteHeader(errJson.StatusCode())
 	if _, err := io.Copy(w, io.NopCloser(bytes.NewReader(j))); err != nil {
 		log.WithError(err).Error("Could not write error message")
--- a/api/server/middleware/BUILD.bazel
+++ b/api/server/middleware/BUILD.bazel
@@ -19,7 +19,7 @@ go_test(
    ],
    embed = [":go_default_library"],
    deps = [
-        "//api:go_default_library",
+        "//api/httputil:go_default_library",
        "//testing/assert:go_default_library",
        "//testing/require:go_default_library",
    ],
--- a/api/server/middleware/middleware_test.go
+++ b/api/server/middleware/middleware_test.go
@@ -5,7 +5,7 @@ import (
 	"net/http/httptest"
 	"testing"

-	"github.com/prysmaticlabs/prysm/v5/api"
+	"github.com/prysmaticlabs/prysm/v5/api/httputil"
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
 )

@@ -55,7 +55,7 @@ func TestNormalizeQueryValuesHandler(t *testing.T) {
 }

 func TestContentTypeHandler(t *testing.T) {
-	acceptedMediaTypes := []string{api.JsonMediaType, api.OctetStreamMediaType}
+	acceptedMediaTypes := []string{httputil.JsonMediaType, httputil.OctetStreamMediaType}

 	nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		_, err := w.Write([]byte("next handler"))
@@ -72,12 +72,12 @@ func TestContentTypeHandler(t *testing.T) {
 	}{
 		{
 			name:               "Accepted Content-Type - application/json",
-			contentType:        api.JsonMediaType,
+			contentType:        httputil.JsonMediaType,
 			expectedStatusCode: http.StatusOK,
 		},
 		{
 			name:               "Accepted Content-Type - ssz format",
-			contentType:        api.OctetStreamMediaType,
+			contentType:        httputil.OctetStreamMediaType,
 			expectedStatusCode: http.StatusOK,
 		},
 		{
--- a/api/server/structs/endpoints_beacon.go
+++ b/api/server/structs/endpoints_beacon.go
@@ -78,8 +78,8 @@ type GetBlockHeaderResponse struct {
 }

 type GetValidatorsRequest struct {
-	Ids      []string `json:"ids"`
-	Statuses []string `json:"statuses"`
+	Ids      []string `json:"ids,omitempty"`
+	Statuses []string `json:"statuses,omitempty"`
 }

 type GetValidatorsResponse struct {
@@ -100,6 +100,12 @@ type GetValidatorBalancesResponse struct {
 	Data                []*ValidatorBalance `json:"data"`
 }

+type GetValidatorIdentitiesResponse struct {
+	ExecutionOptimistic bool                 `json:"execution_optimistic"`
+	Finalized           bool                 `json:"finalized"`
+	Data                []*ValidatorIdentity `json:"data"`
+}
+
 type ValidatorContainer struct {
 	Index     string     `json:"index"`
 	Balance   string     `json:"balance"`
@@ -112,6 +118,12 @@ type ValidatorBalance struct {
 	Balance string `json:"balance"`
 }

+type ValidatorIdentity struct {
+	Index           string `json:"index"`
+	Pubkey          string `json:"pubkey"`
+	ActivationEpoch string `json:"activation_epoch"`
+}
+
 type GetBlockResponse struct {
 	Data *SignedBlock `json:"data"`
 }
--- a/api/server/structs/endpoints_debug.go
+++ b/api/server/structs/endpoints_debug.go
@@ -54,4 +54,5 @@ type ForkChoiceNodeExtraData struct {
 	Balance                  string `json:"balance"`
 	ExecutionOptimistic      bool   `json:"execution_optimistic"`
 	TimeStamp                string `json:"timestamp"`
+	Target                   string `json:"target"`
 }
--- a/api/server/structs/endpoints_events.go
+++ b/api/server/structs/endpoints_events.go
@@ -20,6 +20,11 @@ type BlockEvent struct {
 	ExecutionOptimistic bool   `json:"execution_optimistic"`
 }

+type BlockGossipEvent struct {
+	Slot  string `json:"slot"`
+	Block string `json:"block"`
+}
+
 type AggregatedAttEventSource struct {
 	Aggregate *Attestation `json:"aggregate"`
 }
--- a/async/event/subscription.go
+++ b/async/event/subscription.go
@@ -154,7 +154,7 @@ retry:
 				continue retry
 			}
 			if sub == nil {
-				panic("event: ResubscribeFunc returned nil subscription and no error")
+				panic("event: ResubscribeFunc returned nil subscription and no error") // lint:nopanic -- This should never happen.
 			}
 			return sub
 		case <-s.unsub:
--- a/beacon-chain/blockchain/BUILD.bazel
+++ b/beacon-chain/blockchain/BUILD.bazel
@@ -26,6 +26,7 @@ go_library(
        "receive_blob.go",
        "receive_block.go",
        "service.go",
+        "setup_forchoice.go",
        "tracked_proposer.go",
        "weak_subjectivity_checks.go",
    ],
@@ -96,6 +97,7 @@ go_library(
        "@com_github_pkg_errors//:go_default_library",
        "@com_github_prometheus_client_golang//prometheus:go_default_library",
        "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
+        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
        "@org_golang_x_sync//errgroup:go_default_library",
    ],
@@ -126,6 +128,7 @@ go_test(
        "receive_block_test.go",
        "service_norace_test.go",
        "service_test.go",
+        "setup_forkchoice_test.go",
        "setup_test.go",
        "weak_subjectivity_checks_test.go",
    ],
@@ -154,6 +157,7 @@ go_test(
        "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
        "//beacon-chain/forkchoice/types:go_default_library",
        "//beacon-chain/operations/attestations:go_default_library",
+        "//beacon-chain/operations/attestations/kv:go_default_library",
        "//beacon-chain/operations/blstoexec:go_default_library",
        "//beacon-chain/operations/slashings:go_default_library",
        "//beacon-chain/operations/voluntaryexits:go_default_library",
@@ -185,6 +189,7 @@ go_test(
        "@com_github_ethereum_go_ethereum//core/types:go_default_library",
        "@com_github_holiman_uint256//: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",
        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
        "@org_golang_google_protobuf//proto:go_default_library",
--- a/beacon-chain/blockchain/chain_info_forkchoice.go
+++ b/beacon-chain/blockchain/chain_info_forkchoice.go
@@ -3,10 +3,13 @@ package blockchain
 import (
 	"context"

+	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
 	consensus_blocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/forkchoice"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 )

 // CachedHeadRoot returns the corresponding value from Forkchoice
@@ -100,3 +103,26 @@ func (s *Service) ParentRoot(root [32]byte) ([32]byte, error) {
 	defer s.cfg.ForkChoiceStore.RUnlock()
 	return s.cfg.ForkChoiceStore.ParentRoot(root)
 }
+
+// hashForGenesisBlock returns the right hash for the genesis block
+func (s *Service) hashForGenesisBlock(ctx context.Context, root [32]byte) ([]byte, error) {
+	genRoot, err := s.cfg.BeaconDB.GenesisBlockRoot(ctx)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get genesis block root")
+	}
+	if root != genRoot {
+		return nil, errNotGenesisRoot
+	}
+	st, err := s.cfg.BeaconDB.GenesisState(ctx)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get genesis state")
+	}
+	if st.Version() < version.Bellatrix {
+		return nil, nil
+	}
+	header, err := st.LatestExecutionPayloadHeader()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get latest execution payload header")
+	}
+	return bytesutil.SafeCopyBytes(header.BlockHash()), nil
+}
--- a/beacon-chain/blockchain/chain_info_test.go
+++ b/beacon-chain/blockchain/chain_info_test.go
@@ -582,6 +582,7 @@ func TestService_IsOptimisticForRoot_StateSummaryRecovered(t *testing.T) {
 	br, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
 	util.SaveBlock(t, context.Background(), beaconDB, b)
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, [32]byte{}))
 	_, err = c.IsOptimisticForRoot(ctx, br)
 	assert.NoError(t, err)
 	summ, err := beaconDB.StateSummary(ctx, br)
@@ -612,3 +613,20 @@ func TestService_IsFinalized(t *testing.T) {
 	require.Equal(t, true, c.IsFinalized(ctx, br))
 	require.Equal(t, false, c.IsFinalized(ctx, [32]byte{'c'}))
 }
+
+func Test_hashForGenesisRoot(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	ctx := context.Background()
+	c := setupBeaconChain(t, beaconDB)
+	st, _ := util.DeterministicGenesisStateElectra(t, 10)
+	require.NoError(t, c.cfg.BeaconDB.SaveGenesisData(ctx, st))
+	root, err := beaconDB.GenesisBlockRoot(ctx)
+	require.NoError(t, err)
+	genRoot, err := c.hashForGenesisBlock(ctx, [32]byte{'a'})
+	require.ErrorIs(t, err, errNotGenesisRoot)
+	require.IsNil(t, genRoot)
+
+	genRoot, err = c.hashForGenesisBlock(ctx, root)
+	require.NoError(t, err)
+	require.Equal(t, [32]byte{}, [32]byte(genRoot))
+}
--- a/beacon-chain/blockchain/error.go
+++ b/beacon-chain/blockchain/error.go
@@ -30,6 +30,10 @@ var (
 	ErrNotCheckpoint = errors.New("not a checkpoint in forkchoice")
 	// ErrNilHead is returned when no head is present in the blockchain service.
 	ErrNilHead = errors.New("nil head")
+	// errNotGenesisRoot is returned when the root is not the genesis block root.
+	errNotGenesisRoot = errors.New("root is not the genesis block root")
+	// errBlacklistedBlock is returned when a block is blacklisted as invalid.
+	errBlacklistedRoot = errors.New("block root is blacklisted")
 )

 var errMaxBlobsExceeded = errors.New("Expected commitments in block exceeds MAX_BLOBS_PER_BLOCK")
--- a/beacon-chain/blockchain/execution_engine.go
+++ b/beacon-chain/blockchain/execution_engine.go
@@ -69,10 +69,21 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *fcuConfig) (*
 		SafeBlockHash:      justifiedHash[:],
 		FinalizedBlockHash: finalizedHash[:],
 	}
+	if len(fcs.HeadBlockHash) != 32 || [32]byte(fcs.HeadBlockHash) == [32]byte{} {
+		// check if we are sending FCU at genesis
+		hash, err := s.hashForGenesisBlock(ctx, arg.headRoot)
+		if errors.Is(err, errNotGenesisRoot) {
+			log.Error("Sending nil head block hash to execution engine")
+			return nil, nil
+		}
+		if err != nil {
+			return nil, errors.Wrap(err, "could not get head block hash")
+		}
+		fcs.HeadBlockHash = hash
+	}
 	if arg.attributes == nil {
 		arg.attributes = payloadattribute.EmptyWithVersion(headBlk.Version())
 	}
-	go firePayloadAttributesEvent(ctx, s.cfg.StateNotifier.StateFeed(), arg)
 	payloadID, lastValidHash, err := s.cfg.ExecutionEngineCaller.ForkchoiceUpdated(ctx, fcs, arg.attributes)
 	if err != nil {
 		switch {
@@ -159,6 +170,7 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *fcuConfig) (*
 		log.WithFields(logrus.Fields{
 			"blockRoot": fmt.Sprintf("%#x", bytesutil.Trunc(arg.headRoot[:])),
 			"headSlot":  headBlk.Slot(),
+			"nextSlot":  nextSlot,
 			"payloadID": fmt.Sprintf("%#x", bytesutil.Trunc(payloadID[:])),
 		}).Info("Forkchoice updated with payload attributes for proposal")
 		s.cfg.PayloadIDCache.Set(nextSlot, arg.headRoot, pId)
@@ -166,40 +178,19 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *fcuConfig) (*
 		log.WithFields(logrus.Fields{
 			"blockHash": fmt.Sprintf("%#x", headPayload.BlockHash()),
 			"slot":      headBlk.Slot(),
+			"nextSlot":  nextSlot,
 		}).Error("Received nil payload ID on VALID engine response")
 	}
 	return payloadID, nil
 }

-func firePayloadAttributesEvent(ctx context.Context, f event.SubscriberSender, cfg *fcuConfig) {
-	pidx, err := helpers.BeaconProposerIndex(ctx, cfg.headState)
-	if err != nil {
-		log.WithError(err).
-			WithField("head_root", cfg.headRoot[:]).
-			Error("Could not get proposer index for PayloadAttributes event")
-		return
-	}
-	evd := payloadattribute.EventData{
-		ProposerIndex:   pidx,
-		ProposalSlot:    cfg.headState.Slot(),
-		ParentBlockRoot: cfg.headRoot[:],
-		Attributer:      cfg.attributes,
-		HeadRoot:        cfg.headRoot,
-		HeadState:       cfg.headState,
-		HeadBlock:       cfg.headBlock,
-	}
-	if cfg.headBlock != nil && !cfg.headBlock.IsNil() {
-		headPayload, err := cfg.headBlock.Block().Body().Execution()
-		if err != nil {
-			log.WithError(err).Error("Could not get execution payload for head block")
-			return
-		}
-		evd.ParentBlockHash = headPayload.BlockHash()
-		evd.ParentBlockNumber = headPayload.BlockNumber()
-	}
+func firePayloadAttributesEvent(_ context.Context, f event.SubscriberSender, nextSlot primitives.Slot) {
+	// the fcu args have differing amounts of completeness based on the code path,
+	// and there is work we only want to do if a client is actually listening to the events beacon api endpoint.
+	// temporary solution: just fire a blank event and fill in the details in the api handler.
 	f.Send(&feed.Event{
 		Type: statefeed.PayloadAttributes,
-		Data: evd,
+		Data: payloadattribute.EventData{ProposalSlot: nextSlot},
 	})
 }

--- a/beacon-chain/blockchain/execution_engine_test.go
+++ b/beacon-chain/blockchain/execution_engine_test.go
@@ -84,7 +84,7 @@ func Test_NotifyForkchoiceUpdate_GetPayloadAttrErrorCanContinue(t *testing.T) {
 	service.cfg.PayloadIDCache.Set(1, [32]byte{}, [8]byte{})
 	got, err := service.notifyForkchoiceUpdate(ctx, arg)
 	require.NoError(t, err)
-	require.DeepEqual(t, got, pid) // We still get a payload ID even though the state is bad. This means it returns until the end.
+	require.IsNil(t, got)
 }

 func Test_NotifyForkchoiceUpdate(t *testing.T) {
@@ -113,6 +113,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 	state, blkRoot, err = prepareForkchoiceState(ctx, 2, bellatrixBlkRoot, altairBlkRoot, params.BeaconConfig().ZeroHash, ojc, ofc)
 	require.NoError(t, err)
 	require.NoError(t, fcs.InsertNode(ctx, state, blkRoot))
+	badHash := [32]byte{'h'}

 	tests := []struct {
 		name             string
@@ -210,7 +211,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 			blk: func() interfaces.ReadOnlySignedBeaconBlock {
 				b, err := consensusblocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlockBellatrix{Block: &ethpb.BeaconBlockBellatrix{
 					Body: &ethpb.BeaconBlockBodyBellatrix{
-						ExecutionPayload: &v1.ExecutionPayload{},
+						ExecutionPayload: &v1.ExecutionPayload{BlockHash: badHash[:]},
 					},
 				}})
 				require.NoError(t, err)
--- a/beacon-chain/blockchain/forkchoice_update_execution.go
+++ b/beacon-chain/blockchain/forkchoice_update_execution.go
@@ -102,10 +102,10 @@ func (s *Service) forkchoiceUpdateWithExecution(ctx context.Context, args *fcuCo
 		log.WithError(err).Error("could not save head")
 	}

+	go firePayloadAttributesEvent(ctx, s.cfg.StateNotifier.StateFeed(), s.CurrentSlot()+1)
+
 	// Only need to prune attestations from pool if the head has changed.
-	if err := s.pruneAttsFromPool(args.headBlock); err != nil {
-		log.WithError(err).Error("could not prune attestations from pool")
-	}
+	s.pruneAttsFromPool(s.ctx, args.headState, args.headBlock)
 	return nil
 }

--- a/beacon-chain/blockchain/head.go
+++ b/beacon-chain/blockchain/head.go
@@ -410,7 +410,11 @@ func (s *Service) saveOrphanedOperations(ctx context.Context, orphanedRoot [32]b
 					return err
 				}
 			} else {
-				if a.IsAggregated() {
+				if orphanedBlk.Version() >= version.Electra {
+					if err = s.cfg.AttPool.SaveBlockAttestation(a); err != nil {
+						return err
+					}
+				} else if a.IsAggregated() {
 					if err = s.cfg.AttPool.SaveAggregatedAttestation(a); err != nil {
 						return err
 					}
--- a/beacon-chain/blockchain/head_test.go
+++ b/beacon-chain/blockchain/head_test.go
@@ -324,6 +324,72 @@ func TestSaveOrphanedAtts(t *testing.T) {
 	require.DeepEqual(t, wantAtts, atts)
 }

+func TestSaveOrphanedAttsElectra(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)
+	service.genesisTime = time.Now().Add(time.Duration(-10*int64(1)*int64(params.BeaconConfig().SecondsPerSlot)) * time.Second)
+
+	// Chain setup
+	// 0 -- 1 -- 2 -- 3
+	//  \-4
+	st, keys := util.DeterministicGenesisStateElectra(t, 64)
+	blkG, err := util.GenerateFullBlockElectra(st, keys, util.DefaultBlockGenConfig(), 1)
+	assert.NoError(t, err)
+
+	util.SaveBlock(t, ctx, service.cfg.BeaconDB, blkG)
+	rG, err := blkG.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	blk1, err := util.GenerateFullBlockElectra(st, keys, util.DefaultBlockGenConfig(), 2)
+	assert.NoError(t, err)
+	blk1.Block.ParentRoot = rG[:]
+	r1, err := blk1.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	blk2, err := util.GenerateFullBlockElectra(st, keys, util.DefaultBlockGenConfig(), 3)
+	assert.NoError(t, err)
+	blk2.Block.ParentRoot = r1[:]
+	r2, err := blk2.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	blk3, err := util.GenerateFullBlockElectra(st, keys, util.DefaultBlockGenConfig(), 4)
+	assert.NoError(t, err)
+	blk3.Block.ParentRoot = r2[:]
+	r3, err := blk3.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	blk4 := util.NewBeaconBlockElectra()
+	blk4.Block.Slot = 4
+	blk4.Block.ParentRoot = rG[:]
+	r4, err := blk4.Block.HashTreeRoot()
+	require.NoError(t, err)
+	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
+	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
+
+	for _, blk := range []*ethpb.SignedBeaconBlockElectra{blkG, blk1, blk2, blk3, blk4} {
+		r, err := blk.Block.HashTreeRoot()
+		require.NoError(t, err)
+		state, blkRoot, err := prepareForkchoiceState(ctx, blk.Block.Slot, r, bytesutil.ToBytes32(blk.Block.ParentRoot), [32]byte{}, ojc, ofc)
+		require.NoError(t, err)
+		require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
+		util.SaveBlock(t, ctx, beaconDB, blk)
+	}
+
+	require.NoError(t, service.saveOrphanedOperations(ctx, r3, r4))
+	require.Equal(t, 3, len(service.cfg.AttPool.BlockAttestations()))
+	wantAtts := []ethpb.Att{
+		blk3.Block.Body.Attestations[0],
+		blk2.Block.Body.Attestations[0],
+		blk1.Block.Body.Attestations[0],
+	}
+	atts := service.cfg.AttPool.BlockAttestations()
+	sort.Slice(atts, func(i, j int) bool {
+		return atts[i].GetData().Slot > atts[j].GetData().Slot
+	})
+	require.DeepEqual(t, wantAtts, atts)
+}
+
 func TestSaveOrphanedOps(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
 	config := params.BeaconConfig()
--- a/beacon-chain/blockchain/mock_test.go
+++ b/beacon-chain/blockchain/mock_test.go
@@ -3,6 +3,7 @@ package blockchain
 import (
 	"testing"

+	mock "github.com/prysmaticlabs/prysm/v5/beacon-chain/blockchain/testing"
 	testDB "github.com/prysmaticlabs/prysm/v5/beacon-chain/db/testing"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/startup"
@@ -18,6 +19,7 @@ func testServiceOptsWithDB(t *testing.T) []Option {
 		WithStateGen(stategen.New(beaconDB, fcs)),
 		WithForkChoiceStore(fcs),
 		WithClockSynchronizer(cs),
+		WithStateNotifier(&mock.MockStateNotifier{RecordEvents: true}),
 	}
 }

--- a/beacon-chain/blockchain/options.go
+++ b/beacon-chain/blockchain/options.go
@@ -213,3 +213,10 @@ func WithSyncChecker(checker Checker) Option {
 		return nil
 	}
 }
+
+func WithSlasherEnabled(enabled bool) Option {
+	return func(s *Service) error {
+		s.slasherEnabled = enabled
+		return nil
+	}
+}
--- a/beacon-chain/blockchain/process_attestation.go
+++ b/beacon-chain/blockchain/process_attestation.go
@@ -80,7 +80,7 @@ func (s *Service) OnAttestation(ctx context.Context, a ethpb.Att, disparity time
 	}

 	// Use the target state to verify attesting indices are valid.
-	committees, err := helpers.AttestationCommittees(ctx, baseState, a)
+	committees, err := helpers.AttestationCommitteesFromState(ctx, baseState, a)
 	if err != nil {
 		return err
 	}
--- a/beacon-chain/blockchain/process_attestation_helpers.go
+++ b/beacon-chain/blockchain/process_attestation_helpers.go
@@ -18,6 +18,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/time/slots"
 )

+// The caller of this function must have a lock on forkchoice.
 func (s *Service) getRecentPreState(ctx context.Context, c *ethpb.Checkpoint) state.ReadOnlyBeaconState {
 	headEpoch := slots.ToEpoch(s.HeadSlot())
 	if c.Epoch < headEpoch {
@@ -27,13 +28,6 @@ func (s *Service) getRecentPreState(ctx context.Context, c *ethpb.Checkpoint) st
 		return nil
 	}
 	if c.Epoch == headEpoch {
-		targetSlot, err := s.cfg.ForkChoiceStore.Slot([32]byte(c.Root))
-		if err != nil {
-			return nil
-		}
-		if slots.ToEpoch(targetSlot)+1 < headEpoch {
-			return nil
-		}
 		st, err := s.HeadStateReadOnly(ctx)
 		if err != nil {
 			return nil
@@ -65,12 +59,13 @@ func (s *Service) getRecentPreState(ctx context.Context, c *ethpb.Checkpoint) st
 		return nil
 	}
 	if err := s.checkpointStateCache.AddCheckpointState(c, st); err != nil {
-		return nil
+		log.WithError(err).Error("Could not save checkpoint state to cache")
 	}
 	return st
 }

 // getAttPreState retrieves the att pre state by either from the cache or the DB.
+// The caller of this function must have a lock on forkchoice.
 func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (state.ReadOnlyBeaconState, error) {
 	// If the attestation is recent and canonical we can use the head state to compute the shuffling.
 	if st := s.getRecentPreState(ctx, c); st != nil {
--- a/beacon-chain/blockchain/process_block.go
+++ b/beacon-chain/blockchain/process_block.go
@@ -6,6 +6,7 @@ import (
 	"time"

 	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/go-bitfield"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/helpers"
 	coreTime "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/time"
@@ -15,6 +16,7 @@ import (
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v5/config/features"
+	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	consensusblocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
@@ -173,6 +175,9 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 	var set *bls.SignatureBatch
 	boundaries := make(map[[32]byte]state.BeaconState)
 	for i, b := range blks {
+		if features.BlacklistedBlock(b.Root()) {
+			return errBlacklistedRoot
+		}
 		v, h, err := getStateVersionAndPayload(preState)
 		if err != nil {
 			return err
@@ -368,7 +373,7 @@ func (s *Service) handleEpochBoundary(ctx context.Context, slot primitives.Slot,
 func (s *Service) handleBlockAttestations(ctx context.Context, blk interfaces.ReadOnlyBeaconBlock, st state.BeaconState) error {
 	// Feed in block's attestations to fork choice store.
 	for _, a := range blk.Body().Attestations() {
-		committees, err := helpers.AttestationCommittees(ctx, st, a)
+		committees, err := helpers.AttestationCommitteesFromState(ctx, st, a)
 		if err != nil {
 			return err
 		}
@@ -419,24 +424,98 @@ func (s *Service) savePostStateInfo(ctx context.Context, r [32]byte, b interface
 	return nil
 }

-// This removes the attestations in block `b` from the attestation mem pool.
-func (s *Service) pruneAttsFromPool(headBlock interfaces.ReadOnlySignedBeaconBlock) error {
-	atts := headBlock.Block().Body().Attestations()
-	for _, att := range atts {
-		if features.Get().EnableExperimentalAttestationPool {
-			if err := s.cfg.AttestationCache.DeleteCovered(att); err != nil {
-				return errors.Wrap(err, "could not delete attestation")
-			}
-		} else if att.IsAggregated() {
-			if err := s.cfg.AttPool.DeleteAggregatedAttestation(att); err != nil {
-				return err
-			}
-		} else {
-			if err := s.cfg.AttPool.DeleteUnaggregatedAttestation(att); err != nil {
-				return err
-			}
+// pruneAttsFromPool removes these attestations from the attestation pool
+// which are covered by attestations from the received block.
+func (s *Service) pruneAttsFromPool(ctx context.Context, headState state.BeaconState, headBlock interfaces.ReadOnlySignedBeaconBlock) {
+	for _, att := range headBlock.Block().Body().Attestations() {
+		if err := s.pruneCoveredAttsFromPool(ctx, headState, att); err != nil {
+			log.WithError(err).Warn("Could not prune attestations covered by a received block's attestation")
 		}
 	}
+}
+
+func (s *Service) pruneCoveredAttsFromPool(ctx context.Context, headState state.BeaconState, att ethpb.Att) error {
+	switch {
+	case !att.IsAggregated():
+		return s.cfg.AttPool.DeleteUnaggregatedAttestation(att)
+	case att.Version() == version.Phase0:
+		if features.Get().EnableExperimentalAttestationPool {
+			return errors.Wrap(s.cfg.AttestationCache.DeleteCovered(att), "could not delete covered attestation")
+		}
+		return errors.Wrap(s.cfg.AttPool.DeleteAggregatedAttestation(att), "could not delete aggregated attestation")
+	default:
+		return s.pruneCoveredElectraAttsFromPool(ctx, headState, att)
+	}
+}
+
+// pruneCoveredElectraAttsFromPool handles removing aggregated Electra attestations from the pool after receiving a block.
+// Because in Electra block attestations can combine aggregates for multiple committees, comparing attestation bits
+// of a block attestation with attestations bits of an aggregate can cause unexpected results, leading to covered
+// aggregates not being removed from the pool.
+//
+// To make sure aggregates are removed, we decompose the block attestation into dummy aggregates, with each
+// aggregate accounting for one committee. This allows us to compare aggregates in the same way it's done for
+// Phase0. Even though we can't provide a valid signature for the dummy aggregate, it does not matter because
+// signatures play no part in pruning attestations.
+func (s *Service) pruneCoveredElectraAttsFromPool(ctx context.Context, headState state.BeaconState, att ethpb.Att) error {
+	if att.Version() == version.Phase0 {
+		log.Error("Called pruneCoveredElectraAttsFromPool with a Phase0 attestation")
+		return nil
+	}
+
+	// We don't want to recompute committees. If they are not cached already,
+	// we allow attestations to stay in the pool. If these attestations are
+	// included in a later block, they will be redundant. But given that
+	// they were not cached in the first place, it's unlikely that they
+	// will be chosen into a block.
+	ok, committees, err := helpers.AttestationCommitteesFromCache(ctx, headState, att)
+	if err != nil {
+		return errors.Wrap(err, "could not get attestation committees")
+	}
+	if !ok {
+		log.Debug("Attestation committees are not cached. Skipping attestation pruning.")
+		return nil
+	}
+
+	committeeIndices := att.CommitteeBitsVal().BitIndices()
+	offset := uint64(0)
+
+	// Sanity check as this should never happen
+	if len(committeeIndices) != len(committees) {
+		return errors.New("committee indices and committees have different lengths")
+	}
+
+	for i, c := range committees {
+		ab := bitfield.NewBitlist(uint64(len(c)))
+		for j := uint64(0); j < uint64(len(c)); j++ {
+			ab.SetBitAt(j, att.GetAggregationBits().BitAt(j+offset))
+		}
+
+		cb := primitives.NewAttestationCommitteeBits()
+		cb.SetBitAt(uint64(committeeIndices[i]), true)
+
+		a := &ethpb.AttestationElectra{
+			AggregationBits: ab,
+			Data:            att.GetData(),
+			CommitteeBits:   cb,
+			Signature:       make([]byte, fieldparams.BLSSignatureLength),
+		}
+
+		if features.Get().EnableExperimentalAttestationPool {
+			if err = s.cfg.AttestationCache.DeleteCovered(a); err != nil {
+				return errors.Wrap(err, "could not delete covered attestation")
+			}
+		} else if !a.IsAggregated() {
+			if err = s.cfg.AttPool.DeleteUnaggregatedAttestation(a); err != nil {
+				return errors.Wrap(err, "could not delete unaggregated attestation")
+			}
+		} else if err = s.cfg.AttPool.DeleteAggregatedAttestation(a); err != nil {
+			return errors.Wrap(err, "could not delete aggregated attestation")
+		}
+
+		offset += uint64(len(c))
+	}
+
 	return nil
 }

@@ -650,13 +729,9 @@ func (s *Service) lateBlockTasks(ctx context.Context) {
 	attribute := s.getPayloadAttribute(ctx, headState, s.CurrentSlot()+1, headRoot[:])
 	// return early if we are not proposing next slot
 	if attribute.IsEmpty() {
-		fcuArgs := &fcuConfig{
-			headState:  headState,
-			headRoot:   headRoot,
-			headBlock:  nil,
-			attributes: attribute,
-		}
-		go firePayloadAttributesEvent(ctx, s.cfg.StateNotifier.StateFeed(), fcuArgs)
+		// notifyForkchoiceUpdate fires the payload attribute event. But in this case, we won't
+		// call notifyForkchoiceUpdate, so the event is fired here.
+		go firePayloadAttributesEvent(ctx, s.cfg.StateNotifier.StateFeed(), s.CurrentSlot()+1)
 		return
 	}

--- a/beacon-chain/blockchain/process_block_test.go
+++ b/beacon-chain/blockchain/process_block_test.go
@@ -12,8 +12,10 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	gethtypes "github.com/ethereum/go-ethereum/core/types"
 	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/go-bitfield"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/blocks"
+	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/helpers"
 	lightClient "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/light-client"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/signing"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/transition"
@@ -25,6 +27,7 @@ import (
 	mockExecution "github.com/prysmaticlabs/prysm/v5/beacon-chain/execution/testing"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/types"
+	"github.com/prysmaticlabs/prysm/v5/beacon-chain/operations/attestations/kv"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v5/config/features"
 	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
@@ -45,6 +48,94 @@ import (
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )

+func Test_pruneAttsFromPool_Electra(t *testing.T) {
+	ctx := context.Background()
+	logHook := logTest.NewGlobal()
+
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig().Copy()
+	cfg.TargetCommitteeSize = 8
+	params.OverrideBeaconConfig(cfg)
+
+	s := Service{
+		cfg: &config{
+			AttPool: kv.NewAttCaches(),
+		},
+	}
+
+	data := &ethpb.AttestationData{
+		BeaconBlockRoot: make([]byte, 32),
+		Source:          &ethpb.Checkpoint{Root: make([]byte, 32)},
+		Target:          &ethpb.Checkpoint{Root: make([]byte, 32)},
+	}
+
+	cb := primitives.NewAttestationCommitteeBits()
+	cb.SetBitAt(0, true)
+	att1 := &ethpb.AttestationElectra{
+		AggregationBits: bitfield.Bitlist{0b10000000, 0b00000001},
+		Data:            data,
+		Signature:       make([]byte, 96),
+		CommitteeBits:   cb,
+	}
+
+	cb = primitives.NewAttestationCommitteeBits()
+	cb.SetBitAt(1, true)
+	att2 := &ethpb.AttestationElectra{
+		AggregationBits: bitfield.Bitlist{0b11110111, 0b00000001},
+		Data:            data,
+		Signature:       make([]byte, 96),
+		CommitteeBits:   cb,
+	}
+
+	cb = primitives.NewAttestationCommitteeBits()
+	cb.SetBitAt(3, true)
+	att3 := &ethpb.AttestationElectra{
+		AggregationBits: bitfield.Bitlist{0b11110111, 0b00000001},
+		Data:            data,
+		Signature:       make([]byte, 96),
+		CommitteeBits:   cb,
+	}
+
+	require.NoError(t, s.cfg.AttPool.SaveUnaggregatedAttestation(att1))
+	require.NoError(t, s.cfg.AttPool.SaveAggregatedAttestation(att2))
+	require.NoError(t, s.cfg.AttPool.SaveAggregatedAttestation(att3))
+
+	cb = primitives.NewAttestationCommitteeBits()
+	cb.SetBitAt(0, true)
+	cb.SetBitAt(1, true)
+	onChainAtt := &ethpb.AttestationElectra{
+		AggregationBits: bitfield.Bitlist{0b10000000, 0b11110111, 0b00000001},
+		Data:            data,
+		Signature:       make([]byte, 96),
+		CommitteeBits:   cb,
+	}
+	bl := &ethpb.SignedBeaconBlockElectra{
+		Block: &ethpb.BeaconBlockElectra{
+			Body: &ethpb.BeaconBlockBodyElectra{
+				Attestations: []*ethpb.AttestationElectra{onChainAtt},
+			},
+		},
+		Signature: make([]byte, 96),
+	}
+	rob, err := consensusblocks.NewSignedBeaconBlock(bl)
+	require.NoError(t, err)
+	st, _ := util.DeterministicGenesisStateElectra(t, 1024)
+	committees, err := helpers.BeaconCommittees(ctx, st, 0)
+	require.NoError(t, err)
+	// Sanity check to make sure the on-chain att will be decomposed
+	// into the correct number of aggregates.
+	require.Equal(t, 4, len(committees))
+
+	s.pruneAttsFromPool(ctx, st, rob)
+	require.LogsDoNotContain(t, logHook, "Could not prune attestations")
+
+	attsInPool := s.cfg.AttPool.UnaggregatedAttestations()
+	assert.Equal(t, 0, len(attsInPool))
+	attsInPool = s.cfg.AttPool.AggregatedAttestations()
+	require.Equal(t, 1, len(attsInPool))
+	assert.DeepEqual(t, att3, attsInPool[0])
+}
+
 func TestStore_OnBlockBatch(t *testing.T) {
 	service, tr := minimalTestService(t)
 	ctx := tr.ctx
@@ -821,6 +912,8 @@ func TestInsertFinalizedDeposits_MultipleFinalizedRoutines(t *testing.T) {
 }

 func TestRemoveBlockAttestationsInPool(t *testing.T) {
+	logHook := logTest.NewGlobal()
+
 	genesis, keys := util.DeterministicGenesisState(t, 64)
 	b, err := util.GenerateFullBlock(genesis, keys, util.DefaultBlockGenConfig(), 1)
 	assert.NoError(t, err)
@@ -840,7 +933,8 @@ func TestRemoveBlockAttestationsInPool(t *testing.T) {
 	require.NoError(t, service.cfg.AttPool.SaveAggregatedAttestations(atts))
 	wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 	require.NoError(t, err)
-	require.NoError(t, service.pruneAttsFromPool(wsb))
+	service.pruneAttsFromPool(context.Background(), nil /* state not needed pre-Electra */, wsb)
+	require.LogsDoNotContain(t, logHook, "Could not prune attestations")
 	require.Equal(t, 0, service.cfg.AttPool.AggregatedAttestationCount())
 }

@@ -1896,6 +1990,7 @@ func TestNoViableHead_Reboot(t *testing.T) {

 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, genesisState, genesisRoot), "Could not save genesis state")
 	require.NoError(t, service.cfg.BeaconDB.SaveHeadBlockRoot(ctx, genesisRoot), "Could not save genesis state")
+	require.NoError(t, service.cfg.BeaconDB.SaveGenesisBlockRoot(ctx, genesisRoot), "Could not save genesis state")

 	for i := 1; i < 6; i++ {
 		driftGenesisTime(service, int64(i), 0)
@@ -2030,6 +2125,7 @@ func TestNoViableHead_Reboot(t *testing.T) {
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, genesisState, jroot))
 	service.cfg.ForkChoiceStore.SetBalancesByRooter(service.cfg.StateGen.ActiveNonSlashedBalancesByRoot)
 	require.NoError(t, service.StartFromSavedState(genesisState))
+	require.NoError(t, service.cfg.BeaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))

 	// Forkchoice has the genesisRoot loaded at startup
 	require.Equal(t, genesisRoot, service.ensureRootNotZeros(service.cfg.ForkChoiceStore.CachedHeadRoot()))
--- a/beacon-chain/blockchain/receive_block.go
+++ b/beacon-chain/blockchain/receive_block.go
@@ -65,6 +65,10 @@ type SlashingReceiver interface {
 func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, blockRoot [32]byte, avs das.AvailabilityStore) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.ReceiveBlock")
 	defer span.End()
+	// Return early if the block is blacklisted
+	if features.BlacklistedBlock(blockRoot) {
+		return errBlacklistedRoot
+	}
 	// Return early if the block has been synced
 	if s.InForkchoice(blockRoot) {
 		log.WithField("blockRoot", fmt.Sprintf("%#x", blockRoot)).Debug("Ignoring already synced block")
@@ -121,7 +125,7 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 		return err
 	}
 	// If slasher is configured, forward the attestations in the block via an event feed for processing.
-	if features.Get().EnableSlasher {
+	if s.slasherEnabled {
 		go s.sendBlockAttestationsToSlasher(blockCopy, preState)
 	}

@@ -548,7 +552,7 @@ func (s *Service) sendBlockAttestationsToSlasher(signed interfaces.ReadOnlySigne
 	// is done in the background to avoid adding more load to this critical code path.
 	ctx := context.TODO()
 	for _, att := range signed.Block().Body().Attestations() {
-		committees, err := helpers.AttestationCommittees(ctx, preState, att)
+		committees, err := helpers.AttestationCommitteesFromState(ctx, preState, att)
 		if err != nil {
 			log.WithError(err).Error("Could not get attestation committees")
 			return
--- a/beacon-chain/blockchain/receive_block_test.go
+++ b/beacon-chain/blockchain/receive_block_test.go
@@ -12,6 +12,7 @@ import (
 	statefeed "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/das"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/operations/voluntaryexits"
+	"github.com/prysmaticlabs/prysm/v5/config/features"
 	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
@@ -41,6 +42,16 @@ func TestService_ReceiveBlock(t *testing.T) {
 	bc.ShardCommitteePeriod = 0 // Required for voluntary exits test in reasonable time.
 	params.OverrideBeaconConfig(bc)

+	badBlock := genFullBlock(t, util.DefaultBlockGenConfig(), 101)
+	badRoot, err := badBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	badRoots := make(map[[32]byte]struct{})
+	badRoots[badRoot] = struct{}{}
+	resetCfg := features.InitWithReset(&features.Flags{
+		BlacklistedRoots: badRoots,
+	})
+	defer resetCfg()
+
 	type args struct {
 		block *ethpb.SignedBeaconBlock
 	}
@@ -124,8 +135,14 @@ func TestService_ReceiveBlock(t *testing.T) {
 				}
 			},
 		},
+		{
+			name: "The block is blacklisted",
+			args: args{
+				block: badBlock,
+			},
+			wantedErr: errBlacklistedRoot.Error(),
+		},
 	}
-
 	wg := new(sync.WaitGroup)
 	for _, tt := range tests {
 		wg.Add(1)
--- a/beacon-chain/blockchain/service.go
+++ b/beacon-chain/blockchain/service.go
@@ -3,7 +3,6 @@
 package blockchain

 import (
-	"bytes"
 	"context"
 	"fmt"
 	"runtime"
@@ -23,7 +22,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/db/filesystem"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/execution"
 	f "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice"
-	forkchoicetypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/operations/attestations"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/operations/blstoexec"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/operations/slashings"
@@ -32,7 +30,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/startup"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state/stategen"
-	"github.com/prysmaticlabs/prysm/v5/config/features"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
@@ -42,6 +39,7 @@ import (
 	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
 	prysmTime "github.com/prysmaticlabs/prysm/v5/time"
 	"github.com/prysmaticlabs/prysm/v5/time/slots"
+	"github.com/sirupsen/logrus"
 )

 // Service represents a service that handles the internal
@@ -65,6 +63,7 @@ type Service struct {
 	blobNotifiers        *blobNotifierMap
 	blockBeingSynced     *currentlySyncingBlock
 	blobStorage          *filesystem.BlobStorage
+	slasherEnabled       bool
 }

 // config options for the service.
@@ -269,69 +268,18 @@ func (s *Service) StartFromSavedState(saved state.BeaconState) error {
 		return err
 	}
 	s.originBlockRoot = originRoot
-
-	if err := s.initializeHeadFromDB(s.ctx); err != nil {
-		return errors.Wrap(err, "could not set up chain info")
+	st, err := s.cfg.StateGen.Resume(s.ctx, s.cfg.FinalizedStateAtStartUp)
+	if err != nil {
+		return errors.Wrap(err, "could not get finalized state from db")
 	}
 	spawnCountdownIfPreGenesis(s.ctx, s.genesisTime, s.cfg.BeaconDB)
-
-	justified, err := s.cfg.BeaconDB.JustifiedCheckpoint(s.ctx)
-	if err != nil {
-		return errors.Wrap(err, "could not get justified checkpoint")
-	}
-	if justified == nil {
-		return errNilJustifiedCheckpoint
-	}
-	finalized, err := s.cfg.BeaconDB.FinalizedCheckpoint(s.ctx)
-	if err != nil {
-		return errors.Wrap(err, "could not get finalized checkpoint")
-	}
-	if finalized == nil {
-		return errNilFinalizedCheckpoint
-	}
-
-	fRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(finalized.Root))
-	s.cfg.ForkChoiceStore.Lock()
-	defer s.cfg.ForkChoiceStore.Unlock()
-	if err := s.cfg.ForkChoiceStore.UpdateJustifiedCheckpoint(s.ctx, &forkchoicetypes.Checkpoint{Epoch: justified.Epoch,
-		Root: bytesutil.ToBytes32(justified.Root)}); err != nil {
-		return errors.Wrap(err, "could not update forkchoice's justified checkpoint")
-	}
-	if err := s.cfg.ForkChoiceStore.UpdateFinalizedCheckpoint(&forkchoicetypes.Checkpoint{Epoch: finalized.Epoch,
-		Root: bytesutil.ToBytes32(finalized.Root)}); err != nil {
-		return errors.Wrap(err, "could not update forkchoice's finalized checkpoint")
-	}
-	s.cfg.ForkChoiceStore.SetGenesisTime(uint64(s.genesisTime.Unix()))
-
-	st, err := s.cfg.StateGen.StateByRoot(s.ctx, fRoot)
-	if err != nil {
-		return errors.Wrap(err, "could not get finalized checkpoint state")
-	}
-	finalizedBlock, err := s.cfg.BeaconDB.Block(s.ctx, fRoot)
-	if err != nil {
-		return errors.Wrap(err, "could not get finalized checkpoint block")
-	}
-	roblock, err := blocks.NewROBlockWithRoot(finalizedBlock, fRoot)
-	if err != nil {
-		return err
-	}
-	if err := s.cfg.ForkChoiceStore.InsertNode(s.ctx, st, roblock); err != nil {
-		return errors.Wrap(err, "could not insert finalized block to forkchoice")
-	}
-	if !features.Get().EnableStartOptimistic {
-		lastValidatedCheckpoint, err := s.cfg.BeaconDB.LastValidatedCheckpoint(s.ctx)
-		if err != nil {
-			return errors.Wrap(err, "could not get last validated checkpoint")
-		}
-		if bytes.Equal(finalized.Root, lastValidatedCheckpoint.Root) {
-			if err := s.cfg.ForkChoiceStore.SetOptimisticToValid(s.ctx, fRoot); err != nil {
-				return errors.Wrap(err, "could not set finalized block as validated")
-			}
-		}
+	if err := s.setupForkchoice(st); err != nil {
+		return errors.Wrap(err, "could not set up forkchoice")
 	}
 	// not attempting to save initial sync blocks here, because there shouldn't be any until
 	// after the statefeed.Initialized event is fired (below)
-	if err := s.wsVerifier.VerifyWeakSubjectivity(s.ctx, finalized.Epoch); err != nil {
+	cp := s.FinalizedCheckpt()
+	if err := s.wsVerifier.VerifyWeakSubjectivity(s.ctx, cp.Epoch); err != nil {
 		// Exit run time if the node failed to verify weak subjectivity checkpoint.
 		return errors.Wrap(err, "could not verify initial checkpoint provided for chain sync")
 	}
@@ -340,7 +288,6 @@ func (s *Service) StartFromSavedState(saved state.BeaconState) error {
 	if err := s.clockSetter.SetClock(startup.NewClock(s.genesisTime, vr)); err != nil {
 		return errors.Wrap(err, "failed to initialize blockchain service")
 	}
-
 	return nil
 }

@@ -370,45 +317,36 @@ func (s *Service) originRootFromSavedState(ctx context.Context) ([32]byte, error
 	return genesisBlkRoot, nil
 }

-// initializeHeadFromDB uses the finalized checkpoint and head block found in the database to set the current head.
+// initializeHeadFromDB uses the finalized checkpoint and head block root from forkchoice to set the current head.
 // Note that this may block until stategen replays blocks between the finalized and head blocks
 // if the head sync flag was specified and the gap between the finalized and head blocks is at least 128 epochs long.
-func (s *Service) initializeHeadFromDB(ctx context.Context) error {
-	finalized, err := s.cfg.BeaconDB.FinalizedCheckpoint(ctx)
-	if err != nil {
-		return errors.Wrap(err, "could not get finalized checkpoint from db")
-	}
-	if finalized == nil {
-		// This should never happen. At chain start, the finalized checkpoint
-		// would be the genesis state and block.
-		return errors.New("no finalized epoch in the database")
-	}
-	finalizedRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(finalized.Root))
-	var finalizedState state.BeaconState
-
-	finalizedState, err = s.cfg.StateGen.Resume(ctx, s.cfg.FinalizedStateAtStartUp)
-	if err != nil {
-		return errors.Wrap(err, "could not get finalized state from db")
-	}
-
-	if finalizedState == nil || finalizedState.IsNil() {
+func (s *Service) initializeHead(ctx context.Context, st state.BeaconState) error {
+	cp := s.FinalizedCheckpt()
+	fRoot := s.ensureRootNotZeros([32]byte(cp.Root))
+	if st == nil || st.IsNil() {
 		return errors.New("finalized state can't be nil")
 	}

-	finalizedBlock, err := s.getBlock(ctx, finalizedRoot)
+	s.cfg.ForkChoiceStore.RLock()
+	root := s.cfg.ForkChoiceStore.HighestReceivedBlockRoot()
+	s.cfg.ForkChoiceStore.RUnlock()
+	blk, err := s.cfg.BeaconDB.Block(ctx, root)
 	if err != nil {
-		return errors.Wrap(err, "could not get finalized block")
+		return errors.Wrap(err, "could not get head block")
 	}
-	if err := s.setHead(&head{
-		finalizedRoot,
-		finalizedBlock,
-		finalizedState,
-		finalizedBlock.Block().Slot(),
-		false,
-	}); err != nil {
+	if root != fRoot {
+		st, err = s.cfg.StateGen.StateByRoot(ctx, root)
+		if err != nil {
+			return errors.Wrap(err, "could not get head state")
+		}
+	}
+	if err := s.setHead(&head{root, blk, st, blk.Block().Slot(), false}); err != nil {
 		return errors.Wrap(err, "could not set head")
 	}
-
+	log.WithFields(logrus.Fields{
+		"root": fmt.Sprintf("%#x", root),
+		"slot": blk.Block().Slot(),
+	}).Info("Initialized head block from DB")
 	return nil
 }

--- a/beacon-chain/blockchain/setup_forchoice.go
+++ b/beacon-chain/blockchain/setup_forchoice.go
@@ -0,0 +1,175 @@
+package blockchain
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+
+	"github.com/pkg/errors"
+	forkchoicetypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/types"
+	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/v5/config/features"
+	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/v5/time/slots"
+)
+
+func (s *Service) setupForkchoice(st state.BeaconState) error {
+	if err := s.setupForkchoiceCheckpoints(); err != nil {
+		return errors.Wrap(err, "could not set up forkchoice checkpoints")
+	}
+	if err := s.setupForkchoiceTree(st); err != nil {
+		return errors.Wrap(err, "could not set up forkchoice root")
+	}
+	if err := s.initializeHead(s.ctx, st); err != nil {
+		return errors.Wrap(err, "could not initialize head from db")
+	}
+	return nil
+}
+
+func (s *Service) startupHeadRoot() [32]byte {
+	headStr := features.Get().ForceHead
+	cp := s.FinalizedCheckpt()
+	fRoot := s.ensureRootNotZeros([32]byte(cp.Root))
+	if headStr == "" {
+		return fRoot
+	}
+	if headStr == "head" {
+		root, err := s.cfg.BeaconDB.HeadBlockRoot()
+		if err != nil {
+			log.WithError(err).Error("could not get head block root, starting with finalized block as head")
+			return fRoot
+		}
+		log.Infof("Using Head root of %#x", root)
+		return root
+	}
+	root, err := bytesutil.DecodeHexWithLength(headStr, 32)
+	if err != nil {
+		log.WithError(err).Error("could not parse head root, starting with finalized block as head")
+		return fRoot
+	}
+	return [32]byte(root)
+}
+
+func (s *Service) setupForkchoiceTree(st state.BeaconState) error {
+	headRoot := s.startupHeadRoot()
+	cp := s.FinalizedCheckpt()
+	fRoot := s.ensureRootNotZeros([32]byte(cp.Root))
+	if err := s.setupForkchoiceRoot(st); err != nil {
+		return errors.Wrap(err, "could not set up forkchoice root")
+	}
+	if headRoot == fRoot {
+		return nil
+	}
+	blk, err := s.cfg.BeaconDB.Block(s.ctx, headRoot)
+	if err != nil {
+		log.WithError(err).Error("could not get head block, starting with finalized block as head")
+		return nil
+	}
+	if slots.ToEpoch(blk.Block().Slot()) < cp.Epoch {
+		log.WithField("headRoot", fmt.Sprintf("%#x", headRoot)).Error("head block is older than finalized block, starting with finalized block as head")
+		return nil
+	}
+	chain, err := s.buildForkchoiceChain(s.ctx, blk)
+	if err != nil {
+		log.WithError(err).Error("could not build forkchoice chain, starting with finalized block as head")
+		return nil
+	}
+	s.cfg.ForkChoiceStore.Lock()
+	defer s.cfg.ForkChoiceStore.Unlock()
+	return s.cfg.ForkChoiceStore.InsertChain(s.ctx, chain)
+}
+
+func (s *Service) buildForkchoiceChain(ctx context.Context, head interfaces.ReadOnlySignedBeaconBlock) ([]*forkchoicetypes.BlockAndCheckpoints, error) {
+	chain := []*forkchoicetypes.BlockAndCheckpoints{}
+	cp := s.FinalizedCheckpt()
+	fRoot := s.ensureRootNotZeros([32]byte(cp.Root))
+	jp := s.CurrentJustifiedCheckpt()
+	root, err := head.Block().HashTreeRoot()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get head block root")
+	}
+	for {
+		roblock, err := blocks.NewROBlockWithRoot(head, root)
+		if err != nil {
+			return nil, err
+		}
+		// This chain sets the justified checkpoint for every block, including some that are older than jp.
+		// This should be however safe for forkchoice at startup. An alternative would be to hook during the
+		// block processing pipeline when setting the head state, to compute the right states for the justified
+		// checkpoint.
+		chain = append(chain, &forkchoicetypes.BlockAndCheckpoints{Block: roblock, JustifiedCheckpoint: jp, FinalizedCheckpoint: cp})
+		root = head.Block().ParentRoot()
+		if root == fRoot {
+			break
+		}
+		head, err = s.cfg.BeaconDB.Block(s.ctx, root)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not get block")
+		}
+		if slots.ToEpoch(head.Block().Slot()) < cp.Epoch {
+			return nil, errors.New("head block is not a descendant of the finalized checkpoint")
+		}
+	}
+	return chain, nil
+}
+
+func (s *Service) setupForkchoiceRoot(st state.BeaconState) error {
+	cp := s.FinalizedCheckpt()
+	fRoot := s.ensureRootNotZeros([32]byte(cp.Root))
+	finalizedBlock, err := s.cfg.BeaconDB.Block(s.ctx, fRoot)
+	if err != nil {
+		return errors.Wrap(err, "could not get finalized checkpoint block")
+	}
+	roblock, err := blocks.NewROBlockWithRoot(finalizedBlock, fRoot)
+	if err != nil {
+		return err
+	}
+	if err := s.cfg.ForkChoiceStore.InsertNode(s.ctx, st, roblock); err != nil {
+		return errors.Wrap(err, "could not insert finalized block to forkchoice")
+	}
+	if !features.Get().EnableStartOptimistic {
+		lastValidatedCheckpoint, err := s.cfg.BeaconDB.LastValidatedCheckpoint(s.ctx)
+		if err != nil {
+			return errors.Wrap(err, "could not get last validated checkpoint")
+		}
+		if bytes.Equal(fRoot[:], lastValidatedCheckpoint.Root) {
+			if err := s.cfg.ForkChoiceStore.SetOptimisticToValid(s.ctx, fRoot); err != nil {
+				return errors.Wrap(err, "could not set finalized block as validated")
+			}
+		}
+	}
+	return nil
+}
+
+func (s *Service) setupForkchoiceCheckpoints() error {
+	justified, err := s.cfg.BeaconDB.JustifiedCheckpoint(s.ctx)
+	if err != nil {
+		return errors.Wrap(err, "could not get justified checkpoint")
+	}
+	if justified == nil {
+		return errNilJustifiedCheckpoint
+	}
+	finalized, err := s.cfg.BeaconDB.FinalizedCheckpoint(s.ctx)
+	if err != nil {
+		return errors.Wrap(err, "could not get finalized checkpoint")
+	}
+	if finalized == nil {
+		return errNilFinalizedCheckpoint
+	}
+
+	fRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(finalized.Root))
+	s.cfg.ForkChoiceStore.Lock()
+	defer s.cfg.ForkChoiceStore.Unlock()
+	if err := s.cfg.ForkChoiceStore.UpdateJustifiedCheckpoint(s.ctx, &forkchoicetypes.Checkpoint{Epoch: justified.Epoch,
+		Root: bytesutil.ToBytes32(justified.Root)}); err != nil {
+		return errors.Wrap(err, "could not update forkchoice's justified checkpoint")
+	}
+	if err := s.cfg.ForkChoiceStore.UpdateFinalizedCheckpoint(&forkchoicetypes.Checkpoint{Epoch: finalized.Epoch,
+		Root: fRoot}); err != nil {
+		return errors.Wrap(err, "could not update forkchoice's finalized checkpoint")
+	}
+	s.cfg.ForkChoiceStore.SetGenesisTime(uint64(s.genesisTime.Unix()))
+	return nil
+}
--- a/beacon-chain/blockchain/setup_forkchoice_test.go
+++ b/beacon-chain/blockchain/setup_forkchoice_test.go
@@ -0,0 +1,128 @@
+package blockchain
+
+import (
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/blocks"
+	"github.com/prysmaticlabs/prysm/v5/config/features"
+	"github.com/prysmaticlabs/prysm/v5/config/params"
+	consensusblocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
+	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v5/testing/util"
+	logTest "github.com/sirupsen/logrus/hooks/test"
+)
+
+func Test_startupHeadRoot(t *testing.T) {
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx
+	hook := logTest.NewGlobal()
+	cp := service.FinalizedCheckpt()
+	require.DeepEqual(t, cp.Root, params.BeaconConfig().ZeroHash[:])
+	gr := [32]byte{'r', 'o', 'o', 't'}
+	service.originBlockRoot = gr
+	require.NoError(t, service.cfg.BeaconDB.SaveGenesisBlockRoot(ctx, gr))
+	t.Run("start from finalized", func(t *testing.T) {
+		require.Equal(t, service.startupHeadRoot(), gr)
+	})
+	t.Run("head requested, error path", func(t *testing.T) {
+		resetCfg := features.InitWithReset(&features.Flags{
+			ForceHead: "head",
+		})
+		defer resetCfg()
+		require.Equal(t, service.startupHeadRoot(), gr)
+		require.LogsContain(t, hook, "could not get head block root, starting with finalized block as head")
+	})
+
+	st, _ := util.DeterministicGenesisState(t, 64)
+	hr := [32]byte{'h', 'e', 'a', 'd'}
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st, hr), "Could not save genesis state")
+	require.NoError(t, service.cfg.BeaconDB.SaveHeadBlockRoot(ctx, hr), "Could not save genesis state")
+	require.NoError(t, service.cfg.BeaconDB.SaveHeadBlockRoot(ctx, hr))
+
+	t.Run("start from head", func(t *testing.T) {
+		resetCfg := features.InitWithReset(&features.Flags{
+			ForceHead: "head",
+		})
+		defer resetCfg()
+		require.Equal(t, service.startupHeadRoot(), hr)
+	})
+}
+
+func Test_setupForkchoiceTree_Finalized(t *testing.T) {
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx
+
+	st, _ := util.DeterministicGenesisState(t, 64)
+	stateRoot, err := st.HashTreeRoot(ctx)
+	require.NoError(t, err, "Could not hash genesis state")
+
+	require.NoError(t, service.saveGenesisData(ctx, st))
+
+	genesis := blocks.NewGenesisBlock(stateRoot[:])
+	wsb, err := consensusblocks.NewSignedBeaconBlock(genesis)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb), "Could not save genesis block")
+	parentRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err, "Could not get signing root")
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st, parentRoot), "Could not save genesis state")
+	require.NoError(t, service.cfg.BeaconDB.SaveHeadBlockRoot(ctx, parentRoot), "Could not save genesis state")
+	require.NoError(t, service.cfg.BeaconDB.SaveJustifiedCheckpoint(ctx, &ethpb.Checkpoint{Root: parentRoot[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Root: parentRoot[:]}))
+	require.NoError(t, service.setupForkchoiceTree(st))
+	require.Equal(t, 1, service.cfg.ForkChoiceStore.NodeCount())
+}
+
+func Test_setupForkchoiceTree_Head(t *testing.T) {
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx
+	resetCfg := features.InitWithReset(&features.Flags{
+		ForceHead: "head",
+	})
+	defer resetCfg()
+
+	genesisState, keys := util.DeterministicGenesisState(t, 64)
+	stateRoot, err := genesisState.HashTreeRoot(ctx)
+	require.NoError(t, err, "Could not hash genesis state")
+	genesis := blocks.NewGenesisBlock(stateRoot[:])
+	wsb, err := consensusblocks.NewSignedBeaconBlock(genesis)
+	require.NoError(t, err)
+	genesisRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err, "Could not get signing root")
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb), "Could not save genesis block")
+	require.NoError(t, service.saveGenesisData(ctx, genesisState))
+
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, genesisState, genesisRoot), "Could not save genesis state")
+	require.NoError(t, service.cfg.BeaconDB.SaveHeadBlockRoot(ctx, genesisRoot), "Could not save genesis state")
+
+	st, err := service.HeadState(ctx)
+	require.NoError(t, err)
+	b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(1))
+	require.NoError(t, err)
+	wsb, err = consensusblocks.NewSignedBeaconBlock(b)
+	require.NoError(t, err)
+	root, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	preState, err := service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err := service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+
+	b, err = util.GenerateFullBlock(postState, keys, util.DefaultBlockGenConfig(), primitives.Slot(2))
+	require.NoError(t, err)
+	wsb, err = consensusblocks.NewSignedBeaconBlock(b)
+	require.NoError(t, err)
+	root, err = b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, root, wsb, preState))
+
+	require.NoError(t, service.cfg.BeaconDB.SaveHeadBlockRoot(ctx, root))
+	cp := service.FinalizedCheckpt()
+	fRoot := service.ensureRootNotZeros([32]byte(cp.Root))
+	require.NotEqual(t, fRoot, root)
+	require.Equal(t, root, service.startupHeadRoot())
+	require.NoError(t, service.setupForkchoiceTree(st))
+	require.Equal(t, 2, service.cfg.ForkChoiceStore.NodeCount())
+}
--- a/beacon-chain/blockchain/testing/mock.go
+++ b/beacon-chain/blockchain/testing/mock.go
@@ -75,6 +75,7 @@ type ChainService struct {
 	SyncingRoot                 [32]byte
 	Blobs                       []blocks.VerifiedROBlob
 	TargetRoot                  [32]byte
+	MockHeadSlot                *primitives.Slot
 }

 func (s *ChainService) Ancestor(ctx context.Context, root []byte, slot primitives.Slot) ([]byte, error) {
@@ -334,6 +335,9 @@ func (s *ChainService) ReceiveBlock(ctx context.Context, block interfaces.ReadOn

 // HeadSlot mocks HeadSlot method in chain service.
 func (s *ChainService) HeadSlot() primitives.Slot {
+	if s.MockHeadSlot != nil {
+		return *s.MockHeadSlot
+	}
 	if s.State == nil {
 		return 0
 	}
--- a/beacon-chain/builder/BUILD.bazel
+++ b/beacon-chain/builder/BUILD.bazel
@@ -3,6 +3,7 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
    name = "go_default_library",
    srcs = [
+        "log.go",
        "metric.go",
        "option.go",
        "service.go",
--- a/beacon-chain/builder/log.go
+++ b/beacon-chain/builder/log.go
@@ -0,0 +1,5 @@
+package builder
+
+import "github.com/sirupsen/logrus"
+
+var log = logrus.WithField("prefix", "builder")
--- a/beacon-chain/builder/option.go
+++ b/beacon-chain/builder/option.go
@@ -14,10 +14,16 @@ type Option func(s *Service) error
 // FlagOptions for builder service flag configurations.
 func FlagOptions(c *cli.Context) ([]Option, error) {
 	endpoint := c.String(flags.MevRelayEndpoint.Name)
+	sszEnabled := c.Bool(flags.EnableBuilderSSZ.Name)
 	var client *builder.Client
 	if endpoint != "" {
+		var opts []builder.ClientOpt
+		if sszEnabled {
+			log.Info("Using APIs with SSZ enabled")
+			opts = append(opts, builder.WithSSZ())
+		}
 		var err error
-		client, err = builder.NewClient(endpoint)
+		client, err = builder.NewClient(endpoint, opts...)
 		if err != nil {
 			return nil, err
 		}
--- a/beacon-chain/builder/service.go
+++ b/beacon-chain/builder/service.go
@@ -17,7 +17,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing/trace"
 	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	log "github.com/sirupsen/logrus"
 )

 // ErrNoBuilder is used when builder endpoint is not configured.
--- a/beacon-chain/cache/tracked_validators.go
+++ b/beacon-chain/cache/tracked_validators.go
@@ -25,7 +25,7 @@ type (
 	}

 	TrackedValidatorsCache struct {
-		trackedValidators cache.Cache
+		trackedValidators *cache.Cache
 	}
 )

@@ -50,7 +50,7 @@ var (
 // NewTrackedValidatorsCache creates a new cache for tracking validators.
 func NewTrackedValidatorsCache() *TrackedValidatorsCache {
 	return &TrackedValidatorsCache{
-		trackedValidators: *cache.New(defaultExpiration, cleanupInterval),
+		trackedValidators: cache.New(defaultExpiration, cleanupInterval),
 	}
 }

--- a/beacon-chain/core/altair/attestation.go
+++ b/beacon-chain/core/altair/attestation.go
@@ -66,7 +66,7 @@ func ProcessAttestationNoVerifySignature(
 	if err != nil {
 		return nil, err
 	}
-	committees, err := helpers.AttestationCommittees(ctx, beaconState, att)
+	committees, err := helpers.AttestationCommitteesFromState(ctx, beaconState, att)
 	if err != nil {
 		return nil, err
 	}
@@ -165,7 +165,7 @@ func AddValidatorFlag(flag, flagPosition uint8) (uint8, error) {
 //	        if flag_index in participation_flag_indices and not has_flag(epoch_participation[index], flag_index):
 //	            epoch_participation[index] = add_flag(epoch_participation[index], flag_index)
 //	            proposer_reward_numerator += get_base_reward(state, index) * weight
-func EpochParticipation(beaconState state.BeaconState, indices []uint64, epochParticipation []byte, participatedFlags map[uint8]bool, totalBalance uint64) (uint64, []byte, error) {
+func EpochParticipation(beaconState state.ReadOnlyBeaconState, indices []uint64, epochParticipation []byte, participatedFlags map[uint8]bool, totalBalance uint64) (uint64, []byte, error) {
 	cfg := params.BeaconConfig()
 	sourceFlagIndex := cfg.TimelySourceFlagIndex
 	targetFlagIndex := cfg.TimelyTargetFlagIndex
@@ -267,7 +267,7 @@ func RewardProposer(ctx context.Context, beaconState state.BeaconState, proposer
 //	    participation_flag_indices.append(TIMELY_HEAD_FLAG_INDEX)
 //
 //	return participation_flag_indices
-func AttestationParticipationFlagIndices(beaconState state.BeaconState, data *ethpb.AttestationData, delay primitives.Slot) (map[uint8]bool, error) {
+func AttestationParticipationFlagIndices(beaconState state.ReadOnlyBeaconState, data *ethpb.AttestationData, delay primitives.Slot) (map[uint8]bool, error) {
 	currEpoch := time.CurrentEpoch(beaconState)
 	var justifiedCheckpt *ethpb.Checkpoint
 	if data.Target.Epoch == currEpoch {
@@ -312,7 +312,7 @@ func AttestationParticipationFlagIndices(beaconState state.BeaconState, data *et
 //	is_matching_source = data.source == justified_checkpoint
 //	is_matching_target = is_matching_source and data.target.root == get_block_root(state, data.target.epoch)
 //	is_matching_head = is_matching_target and data.beacon_block_root == get_block_root_at_slot(state, data.slot)
-func MatchingStatus(beaconState state.BeaconState, data *ethpb.AttestationData, cp *ethpb.Checkpoint) (matchedSrc, matchedTgt, matchedHead bool, err error) {
+func MatchingStatus(beaconState state.ReadOnlyBeaconState, data *ethpb.AttestationData, cp *ethpb.Checkpoint) (matchedSrc, matchedTgt, matchedHead bool, err error) {
 	matchedSrc = attestation.CheckPointIsEqual(data.Source, cp)

 	r, err := helpers.BlockRoot(beaconState, data.Target.Epoch)
--- a/beacon-chain/core/blocks/signature.go
+++ b/beacon-chain/core/blocks/signature.go
@@ -192,7 +192,7 @@ func createAttestationSignatureBatch(
 	descs := make([]string, len(atts))
 	for i, a := range atts {
 		sigs[i] = a.GetSignature()
-		committees, err := helpers.AttestationCommittees(ctx, beaconState, a)
+		committees, err := helpers.AttestationCommitteesFromState(ctx, beaconState, a)
 		if err != nil {
 			return nil, err
 		}
--- a/beacon-chain/core/electra/BUILD.bazel
+++ b/beacon-chain/core/electra/BUILD.bazel
@@ -29,6 +29,7 @@ go_library(
        "//beacon-chain/core/validators:go_default_library",
        "//beacon-chain/state:go_default_library",
        "//beacon-chain/state/state-native:go_default_library",
+        "//beacon-chain/state/state-native/custom-types:go_default_library",
        "//config/params:go_default_library",
        "//consensus-types/interfaces:go_default_library",
        "//consensus-types/primitives:go_default_library",
@@ -39,6 +40,7 @@ go_library(
        "//monitoring/tracing/trace:go_default_library",
        "//proto/engine/v1:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
+        "//proto/prysm/v1alpha1/attestation:go_default_library",
        "//runtime/version:go_default_library",
        "//time/slots:go_default_library",
        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
@@ -79,7 +81,6 @@ go_test(
        "//consensus-types/blocks:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//crypto/bls:go_default_library",
-        "//crypto/bls/common:go_default_library",
        "//encoding/bytesutil:go_default_library",
        "//proto/engine/v1:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
--- a/beacon-chain/core/electra/attestation.go
+++ b/beacon-chain/core/electra/attestation.go
@@ -1,7 +1,94 @@
 package electra

-import "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/altair"
+import (
+	"context"
+	"fmt"
+
+	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/altair"
+	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/time"
+	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
+	customtypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/state/state-native/custom-types"
+	"github.com/prysmaticlabs/prysm/v5/config/params"
+	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
+	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1/attestation"
+)

 var (
 	ProcessAttestationsNoVerifySignature = altair.ProcessAttestationsNoVerifySignature
 )
+
+// GetProposerRewardNumerator returns the numerator of the proposer reward for an attestation.
+func GetProposerRewardNumerator(
+	ctx context.Context,
+	st state.ReadOnlyBeaconState,
+	att ethpb.Att,
+	totalBalance uint64,
+) (uint64, error) {
+	data := att.GetData()
+
+	delay, err := st.Slot().SafeSubSlot(data.Slot)
+	if err != nil {
+		return 0, fmt.Errorf("attestation slot %d exceeds state slot %d", data.Slot, st.Slot())
+	}
+
+	flags, err := altair.AttestationParticipationFlagIndices(st, data, delay)
+	if err != nil {
+		return 0, err
+	}
+
+	committees, err := helpers.AttestationCommitteesFromState(ctx, st, att)
+	if err != nil {
+		return 0, err
+	}
+
+	indices, err := attestation.AttestingIndices(att, committees...)
+	if err != nil {
+		return 0, err
+	}
+
+	var participation customtypes.ReadOnlyParticipation
+	if data.Target.Epoch == time.CurrentEpoch(st) {
+		participation, err = st.CurrentEpochParticipationReadOnly()
+	} else {
+		participation, err = st.PreviousEpochParticipationReadOnly()
+	}
+	if err != nil {
+		return 0, err
+	}
+
+	cfg := params.BeaconConfig()
+	var rewardNumerator uint64
+	for _, index := range indices {
+		if index >= uint64(participation.Len()) {
+			return 0, fmt.Errorf("index %d exceeds participation length %d", index, participation.Len())
+		}
+
+		br, err := altair.BaseRewardWithTotalBalance(st, primitives.ValidatorIndex(index), totalBalance)
+		if err != nil {
+			return 0, err
+		}
+
+		for _, entry := range []struct {
+			flagIndex uint8
+			weight    uint64
+		}{
+			{cfg.TimelySourceFlagIndex, cfg.TimelySourceWeight},
+			{cfg.TimelyTargetFlagIndex, cfg.TimelyTargetWeight},
+			{cfg.TimelyHeadFlagIndex, cfg.TimelyHeadWeight},
+		} {
+			if flags[entry.flagIndex] { // If set, the validator voted correctly for the attestation given flag index.
+				hasVoted, err := altair.HasValidatorFlag(participation.At(index), entry.flagIndex)
+				if err != nil {
+					return 0, err
+				}
+				if !hasVoted { // If set, the validator has already voted in the beacon state so we don't double count.
+					rewardNumerator += br * entry.weight
+				}
+			}
+		}
+	}
+
+	return rewardNumerator, nil
+}
--- a/beacon-chain/core/electra/consolidations.go
+++ b/beacon-chain/core/electra/consolidations.go
@@ -211,7 +211,7 @@ func ProcessConsolidationRequests(ctx context.Context, st state.BeaconState, req
 		if npc, err := st.NumPendingConsolidations(); err != nil {
 			return fmt.Errorf("failed to fetch number of pending consolidations: %w", err) // This should never happen.
 		} else if npc >= pcLimit {
-			return nil
+			continue
 		}

 		activeBal, err := helpers.TotalActiveBalance(st)
@@ -220,7 +220,7 @@ func ProcessConsolidationRequests(ctx context.Context, st state.BeaconState, req
 		}
 		churnLimit := helpers.ConsolidationChurnLimit(primitives.Gwei(activeBal))
 		if churnLimit <= primitives.Gwei(params.BeaconConfig().MinActivationBalance) {
-			return nil
+			continue
 		}

 		srcIdx, ok := st.ValidatorIndexByPubkey(sourcePubkey)
--- a/beacon-chain/core/electra/consolidations_test.go
+++ b/beacon-chain/core/electra/consolidations_test.go
@@ -415,6 +415,44 @@ func TestProcessConsolidationRequests(t *testing.T) {
 				require.Equal(t, params.BeaconConfig().FarFutureEpoch, src.WithdrawableEpoch, "source validator withdrawable epoch should not be updated")
 			},
 		},
+		{
+			name: "pending consolidations limit reached and compounded consolidation after",
+			state: func() state.BeaconState {
+				st := &eth.BeaconStateElectra{
+					Slot:                  params.BeaconConfig().SlotsPerEpoch.Mul(uint64(params.BeaconConfig().ShardCommitteePeriod)),
+					Validators:            createValidatorsWithTotalActiveBalance(32000000000000000), // 32M ETH
+					PendingConsolidations: make([]*eth.PendingConsolidation, params.BeaconConfig().PendingConsolidationsLimit),
+				}
+				// To allow compounding consolidation requests.
+				st.Validators[3].WithdrawalCredentials[0] = params.BeaconConfig().ETH1AddressWithdrawalPrefixByte
+				s, err := state_native.InitializeFromProtoElectra(st)
+				require.NoError(t, err)
+				return s
+			}(),
+			reqs: []*enginev1.ConsolidationRequest{
+				{
+					SourceAddress: append(bytesutil.PadTo(nil, 19), byte(1)),
+					SourcePubkey:  []byte("val_1"),
+					TargetPubkey:  []byte("val_2"),
+				},
+				{
+					SourceAddress: append(bytesutil.PadTo(nil, 19), byte(3)),
+					SourcePubkey:  []byte("val_3"),
+					TargetPubkey:  []byte("val_3"),
+				},
+			},
+			validate: func(t *testing.T, st state.BeaconState) {
+				// Verify a pending consolidation is created.
+				numPC, err := st.NumPendingConsolidations()
+				require.NoError(t, err)
+				require.Equal(t, params.BeaconConfig().PendingConsolidationsLimit, numPC)
+
+				// Verify that the last consolidation was included
+				src, err := st.ValidatorAtIndex(3)
+				require.NoError(t, err)
+				require.Equal(t, params.BeaconConfig().CompoundingWithdrawalPrefixByte, src.WithdrawalCredentials[0], "source validator was not compounded")
+			},
+		},
 	}

 	for _, tt := range tests {
--- a/beacon-chain/core/electra/deposits.go
+++ b/beacon-chain/core/electra/deposits.go
@@ -374,47 +374,38 @@ func ProcessPendingDeposits(ctx context.Context, st state.BeaconState, activeBal

 // batchProcessNewPendingDeposits should only be used to process new deposits that require validator registration
 func batchProcessNewPendingDeposits(ctx context.Context, state state.BeaconState, pendingDeposits []*ethpb.PendingDeposit) error {
-	// Return early if there are no deposits to process
 	if len(pendingDeposits) == 0 {
 		return nil
 	}

-	// Try batch verification of all deposit signatures
 	allSignaturesVerified, err := blocks.BatchVerifyPendingDepositsSignatures(ctx, pendingDeposits)
 	if err != nil {
 		return errors.Wrap(err, "batch signature verification failed")
 	}

-	// Process each deposit individually
-	for _, pendingDeposit := range pendingDeposits {
-		validSignature := allSignaturesVerified
+	for _, pd := range pendingDeposits {
+		validSig := allSignaturesVerified

-		// If batch verification failed, check the individual deposit signature
 		if !allSignaturesVerified {
-			validSignature, err = blocks.IsValidDepositSignature(&ethpb.Deposit_Data{
-				PublicKey:             bytesutil.SafeCopyBytes(pendingDeposit.PublicKey),
-				WithdrawalCredentials: bytesutil.SafeCopyBytes(pendingDeposit.WithdrawalCredentials),
-				Amount:                pendingDeposit.Amount,
-				Signature:             bytesutil.SafeCopyBytes(pendingDeposit.Signature),
+			validSig, err = blocks.IsValidDepositSignature(&ethpb.Deposit_Data{
+				PublicKey:             bytesutil.SafeCopyBytes(pd.PublicKey),
+				WithdrawalCredentials: bytesutil.SafeCopyBytes(pd.WithdrawalCredentials),
+				Amount:                pd.Amount,
+				Signature:             bytesutil.SafeCopyBytes(pd.Signature),
 			})
 			if err != nil {
 				return errors.Wrap(err, "individual deposit signature verification failed")
 			}
 		}

-		// Add validator to the registry if the signature is valid
-		if validSignature {
-			_, has := state.ValidatorIndexByPubkey(bytesutil.ToBytes48(pendingDeposit.PublicKey))
-			if has {
-				index, _ := state.ValidatorIndexByPubkey(bytesutil.ToBytes48(pendingDeposit.PublicKey))
-				if err := helpers.IncreaseBalance(state, index, pendingDeposit.Amount); err != nil {
-					return errors.Wrap(err, "could not increase balance")
-				}
-			} else {
-				err = AddValidatorToRegistry(state, pendingDeposit.PublicKey, pendingDeposit.WithdrawalCredentials, pendingDeposit.Amount)
-				if err != nil {
-					return errors.Wrap(err, "failed to add validator to registry")
-				}
+		pubkey := bytesutil.ToBytes48(pd.PublicKey)
+		if index, exists := state.ValidatorIndexByPubkey(pubkey); exists {
+			if err := helpers.IncreaseBalance(state, index, pd.Amount); err != nil {
+				return errors.Wrap(err, "could not increase balance")
+			}
+		} else if validSig {
+			if err := AddValidatorToRegistry(state, pd.PublicKey, pd.WithdrawalCredentials, pd.Amount); err != nil {
+				return errors.Wrap(err, "failed to add validator to registry")
 			}
 		}
 	}
--- a/beacon-chain/core/electra/deposits_test.go
+++ b/beacon-chain/core/electra/deposits_test.go
@@ -14,7 +14,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v5/crypto/bls"
-	"github.com/prysmaticlabs/prysm/v5/crypto/bls/common"
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
 	enginev1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
 	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
@@ -196,7 +195,7 @@ func TestProcessPendingDeposits(t *testing.T) {
 			},
 		},
 		{
-			name: "process excess balance that uses a point to infinity signature, processed as a topup",
+			name: "process excess balance as a topup",
 			state: func() state.BeaconState {
 				excessBalance := uint64(100)
 				st := stateWithActiveBalanceETH(t, 32)
@@ -209,7 +208,6 @@ func TestProcessPendingDeposits(t *testing.T) {
 				validators[0].PublicKey = sk.PublicKey().Marshal()
 				validators[0].WithdrawalCredentials = wc
 				dep := stateTesting.GeneratePendingDeposit(t, sk, excessBalance, bytesutil.ToBytes32(wc), 0)
-				dep.Signature = common.InfiniteSignature[:]
 				require.NoError(t, st.SetValidators(validators))
 				require.NoError(t, st.SetPendingDeposits([]*eth.PendingDeposit{dep}))
 				return st
@@ -309,7 +307,7 @@ func TestProcessPendingDeposits(t *testing.T) {
 }

 func TestBatchProcessNewPendingDeposits(t *testing.T) {
-	t.Run("invalid batch initiates correct individual validation", func(t *testing.T) {
+	t.Run("one valid deposit one garbage deposit", func(t *testing.T) {
 		st := stateWithActiveBalanceETH(t, 0)
 		require.Equal(t, 0, len(st.Validators()))
 		require.Equal(t, 0, len(st.Balances()))
@@ -320,13 +318,47 @@ func TestBatchProcessNewPendingDeposits(t *testing.T) {
 		wc[31] = byte(0)
 		validDep := stateTesting.GeneratePendingDeposit(t, sk, params.BeaconConfig().MinActivationBalance, bytesutil.ToBytes32(wc), 0)
 		invalidDep := &eth.PendingDeposit{PublicKey: make([]byte, 48)}
-		// have a combination of valid and invalid deposits
 		deps := []*eth.PendingDeposit{validDep, invalidDep}
 		require.NoError(t, electra.BatchProcessNewPendingDeposits(context.Background(), st, deps))
-		// successfully added to register
 		require.Equal(t, 1, len(st.Validators()))
 		require.Equal(t, 1, len(st.Balances()))
 	})
+
+	t.Run("two valid deposits from same key", func(t *testing.T) {
+		st := stateWithActiveBalanceETH(t, 0)
+		require.Equal(t, 0, len(st.Validators()))
+		require.Equal(t, 0, len(st.Balances()))
+		sk, err := bls.RandKey()
+		require.NoError(t, err)
+		wc := make([]byte, 32)
+		wc[0] = params.BeaconConfig().ETH1AddressWithdrawalPrefixByte
+		wc[31] = byte(0)
+		validDep := stateTesting.GeneratePendingDeposit(t, sk, params.BeaconConfig().MinActivationBalance, bytesutil.ToBytes32(wc), 0)
+		deps := []*eth.PendingDeposit{validDep, validDep}
+		require.NoError(t, electra.BatchProcessNewPendingDeposits(context.Background(), st, deps))
+		require.Equal(t, 1, len(st.Validators()))
+		require.Equal(t, 1, len(st.Balances()))
+		require.Equal(t, params.BeaconConfig().MinActivationBalance*2, st.Balances()[0])
+	})
+
+	t.Run("one valid one with invalid signature deposit", func(t *testing.T) {
+		st := stateWithActiveBalanceETH(t, 0)
+		require.Equal(t, 0, len(st.Validators()))
+		require.Equal(t, 0, len(st.Balances()))
+		sk, err := bls.RandKey()
+		require.NoError(t, err)
+		wc := make([]byte, 32)
+		wc[0] = params.BeaconConfig().ETH1AddressWithdrawalPrefixByte
+		wc[31] = byte(0)
+		validDep := stateTesting.GeneratePendingDeposit(t, sk, params.BeaconConfig().MinActivationBalance, bytesutil.ToBytes32(wc), 0)
+		invalidSigDep := stateTesting.GeneratePendingDeposit(t, sk, params.BeaconConfig().MinActivationBalance, bytesutil.ToBytes32(wc), 0)
+		invalidSigDep.Signature = make([]byte, 96)
+		deps := []*eth.PendingDeposit{validDep, invalidSigDep}
+		require.NoError(t, electra.BatchProcessNewPendingDeposits(context.Background(), st, deps))
+		require.Equal(t, 1, len(st.Validators()))
+		require.Equal(t, 1, len(st.Balances()))
+		require.Equal(t, 2*params.BeaconConfig().MinActivationBalance, st.Balances()[0])
+	})
 }

 func TestProcessDepositRequests(t *testing.T) {
@@ -558,7 +590,6 @@ func TestApplyPendingDeposit_TopUp(t *testing.T) {
 	validators[0].PublicKey = sk.PublicKey().Marshal()
 	validators[0].WithdrawalCredentials = wc
 	dep := stateTesting.GeneratePendingDeposit(t, sk, excessBalance, bytesutil.ToBytes32(wc), 0)
-	dep.Signature = common.InfiniteSignature[:]
 	require.NoError(t, st.SetValidators(validators))

 	require.NoError(t, electra.ApplyPendingDeposit(context.Background(), st, dep))
--- a/beacon-chain/core/feed/operation/BUILD.bazel
+++ b/beacon-chain/core/feed/operation/BUILD.bazel
@@ -11,6 +11,7 @@ go_library(
    deps = [
        "//async/event:go_default_library",
        "//consensus-types/blocks:go_default_library",
+        "//consensus-types/interfaces:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
    ],
 )
--- a/beacon-chain/core/feed/operation/events.go
+++ b/beacon-chain/core/feed/operation/events.go
@@ -3,6 +3,7 @@ package operation

 import (
 	"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"
 )

@@ -35,6 +36,9 @@ const (

 	// SingleAttReceived is sent after a single attestation object is received from gossip or rpc
 	SingleAttReceived = 9
+
+	// BlockGossipReceived is sent after a block has been received from gossip or API that passes validation rules.
+	BlockGossipReceived = 10
 )

 // UnAggregatedAttReceivedData is the data sent with UnaggregatedAttReceived events.
@@ -85,3 +89,9 @@ type AttesterSlashingReceivedData struct {
 type SingleAttReceivedData struct {
 	Attestation ethpb.Att
 }
+
+// BlockGossipReceivedData is the data sent with BlockGossipReceived events.
+type BlockGossipReceivedData struct {
+	// SignedBlock is the block that was received.
+	SignedBlock interfaces.ReadOnlySignedBeaconBlock
+}
--- a/beacon-chain/core/helpers/attestation.go
+++ b/beacon-chain/core/helpers/attestation.go
@@ -10,7 +10,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v5/crypto/hash"
 	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 	prysmTime "github.com/prysmaticlabs/prysm/v5/time"
 	"github.com/prysmaticlabs/prysm/v5/time/slots"
 )
@@ -86,15 +85,7 @@ func IsAggregator(committeeCount uint64, slotSig []byte) (bool, error) {
 //
 //	return uint64((committees_since_epoch_start + committee_index) % ATTESTATION_SUBNET_COUNT)
 func ComputeSubnetForAttestation(activeValCount uint64, att ethpb.Att) uint64 {
-	if att.Version() >= version.Electra {
-		committeeIndex := 0
-		committeeIndices := att.CommitteeBitsVal().BitIndices()
-		if len(committeeIndices) > 0 {
-			committeeIndex = committeeIndices[0]
-		}
-		return ComputeSubnetFromCommitteeAndSlot(activeValCount, primitives.CommitteeIndex(committeeIndex), att.GetData().Slot)
-	}
-	return ComputeSubnetFromCommitteeAndSlot(activeValCount, att.GetData().CommitteeIndex, att.GetData().Slot)
+	return ComputeSubnetFromCommitteeAndSlot(activeValCount, att.GetCommitteeIndex(), att.GetData().Slot)
 }

 // ComputeSubnetFromCommitteeAndSlot is a flattened version of ComputeSubnetForAttestation where we only pass in
--- a/beacon-chain/core/helpers/beacon_committee.go
+++ b/beacon-chain/core/helpers/beacon_committee.go
@@ -30,6 +30,13 @@ var (
 	proposerIndicesCache = cache.NewProposerIndicesCache()
 )

+type beaconCommitteeFunc = func(
+	ctx context.Context,
+	state state.ReadOnlyBeaconState,
+	slot primitives.Slot,
+	committeeIndex primitives.CommitteeIndex,
+) ([]primitives.ValidatorIndex, error)
+
 // SlotCommitteeCount returns the number of beacon committees of a slot. The
 // active validator count is provided as an argument rather than an imported implementation
 // from the spec definition. Having the active validator count as an argument allows for
@@ -59,21 +66,48 @@ func SlotCommitteeCount(activeValidatorCount uint64) uint64 {
 	return committeesPerSlot
 }

-// AttestationCommittees returns beacon state committees that reflect attestation's committee indices.
-func AttestationCommittees(ctx context.Context, st state.ReadOnlyBeaconState, att ethpb.Att) ([][]primitives.ValidatorIndex, error) {
+// AttestationCommitteesFromState returns beacon state committees that reflect attestation's committee indices.
+func AttestationCommitteesFromState(ctx context.Context, st state.ReadOnlyBeaconState, att ethpb.Att) ([][]primitives.ValidatorIndex, error) {
+	return attestationCommittees(ctx, st, att, BeaconCommitteeFromState)
+}
+
+// AttestationCommitteesFromCache has the same functionality as AttestationCommitteesFromState, but only returns a value
+// when all attestation committees are already cached.
+func AttestationCommitteesFromCache(ctx context.Context, st state.ReadOnlyBeaconState, att ethpb.Att) (bool, [][]primitives.ValidatorIndex, error) {
+	committees, err := attestationCommittees(ctx, st, att, BeaconCommitteeFromCache)
+	if err != nil {
+		return false, nil, err
+	}
+	if len(committees) == 0 {
+		return false, nil, nil
+	}
+	for _, c := range committees {
+		if len(c) == 0 {
+			return false, nil, nil
+		}
+	}
+	return true, committees, nil
+}
+
+func attestationCommittees(
+	ctx context.Context,
+	st state.ReadOnlyBeaconState,
+	att ethpb.Att,
+	committeeFunc beaconCommitteeFunc,
+) ([][]primitives.ValidatorIndex, error) {
 	var committees [][]primitives.ValidatorIndex
 	if att.Version() >= version.Electra {
 		committeeIndices := att.CommitteeBitsVal().BitIndices()
 		committees = make([][]primitives.ValidatorIndex, len(committeeIndices))
 		for i, ci := range committeeIndices {
-			committee, err := BeaconCommitteeFromState(ctx, st, att.GetData().Slot, primitives.CommitteeIndex(ci))
+			committee, err := committeeFunc(ctx, st, att.GetData().Slot, primitives.CommitteeIndex(ci))
 			if err != nil {
 				return nil, err
 			}
 			committees[i] = committee
 		}
 	} else {
-		committee, err := BeaconCommitteeFromState(ctx, st, att.GetData().Slot, att.GetData().CommitteeIndex)
+		committee, err := committeeFunc(ctx, st, att.GetData().Slot, att.GetData().CommitteeIndex)
 		if err != nil {
 			return nil, err
 		}
@@ -164,6 +198,27 @@ func BeaconCommitteeFromState(ctx context.Context, state state.ReadOnlyBeaconSta
 	return BeaconCommittee(ctx, activeIndices, seed, slot, committeeIndex)
 }

+// BeaconCommitteeFromCache has the same functionality as BeaconCommitteeFromState, but only returns a value
+// when the committee is already cached.
+func BeaconCommitteeFromCache(
+	ctx context.Context,
+	state state.ReadOnlyBeaconState,
+	slot primitives.Slot,
+	committeeIndex primitives.CommitteeIndex,
+) ([]primitives.ValidatorIndex, error) {
+	epoch := slots.ToEpoch(slot)
+	seed, err := Seed(state, epoch, params.BeaconConfig().DomainBeaconAttester)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get seed")
+	}
+
+	committee, err := committeeCache.Committee(ctx, slot, seed, committeeIndex)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not interface with committee cache")
+	}
+	return committee, nil
+}
+
 // BeaconCommittee returns the beacon committee of a given slot and committee index. The
 // validator indices and seed are provided as an argument rather than an imported implementation
 // from the spec definition. Having them as an argument allows for cheaper computation run time.
--- a/beacon-chain/core/helpers/beacon_committee_test.go
+++ b/beacon-chain/core/helpers/beacon_committee_test.go
@@ -729,7 +729,9 @@ func TestCommitteeIndices(t *testing.T) {
 	assert.DeepEqual(t, []primitives.CommitteeIndex{0, 1, 3}, indices)
 }

-func TestAttestationCommittees(t *testing.T) {
+func TestAttestationCommitteesFromState(t *testing.T) {
+	ctx := context.Background()
+
 	validators := make([]*ethpb.Validator, params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().TargetCommitteeSize))
 	for i := 0; i < len(validators); i++ {
 		validators[i] = &ethpb.Validator{
@@ -745,7 +747,7 @@ func TestAttestationCommittees(t *testing.T) {

 	t.Run("pre-Electra", func(t *testing.T) {
 		att := &ethpb.Attestation{Data: &ethpb.AttestationData{CommitteeIndex: 0}}
-		committees, err := helpers.AttestationCommittees(context.Background(), state, att)
+		committees, err := helpers.AttestationCommitteesFromState(ctx, state, att)
 		require.NoError(t, err)
 		require.Equal(t, 1, len(committees))
 		assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(committees[0])))
@@ -755,7 +757,7 @@ func TestAttestationCommittees(t *testing.T) {
 		bits.SetBitAt(0, true)
 		bits.SetBitAt(1, true)
 		att := &ethpb.AttestationElectra{CommitteeBits: bits, Data: &ethpb.AttestationData{}}
-		committees, err := helpers.AttestationCommittees(context.Background(), state, att)
+		committees, err := helpers.AttestationCommitteesFromState(ctx, state, att)
 		require.NoError(t, err)
 		require.Equal(t, 2, len(committees))
 		assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(committees[0])))
@@ -763,9 +765,58 @@ func TestAttestationCommittees(t *testing.T) {
 	})
 }

-func TestBeaconCommittees(t *testing.T) {
-	prevConfig := params.BeaconConfig().Copy()
-	defer params.OverrideBeaconConfig(prevConfig)
+func TestAttestationCommitteesFromCache(t *testing.T) {
+	ctx := context.Background()
+
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().TargetCommitteeSize))
+	for i := 0; i < len(validators); i++ {
+		validators[i] = &ethpb.Validator{
+			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
+		}
+	}
+
+	state, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
+		Validators:  validators,
+		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
+	})
+	require.NoError(t, err)
+
+	t.Run("pre-Electra", func(t *testing.T) {
+		helpers.ClearCache()
+		att := &ethpb.Attestation{Data: &ethpb.AttestationData{CommitteeIndex: 0}}
+		ok, _, err := helpers.AttestationCommitteesFromCache(ctx, state, att)
+		require.NoError(t, err)
+		require.Equal(t, false, ok)
+		require.NoError(t, helpers.UpdateCommitteeCache(ctx, state, 0))
+		ok, committees, err := helpers.AttestationCommitteesFromCache(ctx, state, att)
+		require.NoError(t, err)
+		require.Equal(t, true, ok)
+		require.Equal(t, 1, len(committees))
+		assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(committees[0])))
+	})
+	t.Run("post-Electra", func(t *testing.T) {
+		helpers.ClearCache()
+		bits := primitives.NewAttestationCommitteeBits()
+		bits.SetBitAt(0, true)
+		bits.SetBitAt(1, true)
+		att := &ethpb.AttestationElectra{CommitteeBits: bits, Data: &ethpb.AttestationData{}}
+		ok, _, err := helpers.AttestationCommitteesFromCache(ctx, state, att)
+		require.NoError(t, err)
+		require.Equal(t, false, ok)
+		require.NoError(t, helpers.UpdateCommitteeCache(ctx, state, 0))
+		ok, committees, err := helpers.AttestationCommitteesFromCache(ctx, state, att)
+		require.NoError(t, err)
+		require.Equal(t, true, ok)
+		require.Equal(t, 2, len(committees))
+		assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(committees[0])))
+		assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(committees[1])))
+	})
+}
+
+func TestBeaconCommitteesFromState(t *testing.T) {
+	ctx := context.Background()
+
+	params.SetupTestConfigCleanup(t)
 	c := params.BeaconConfig().Copy()
 	c.MinGenesisActiveValidatorCount = 128
 	c.SlotsPerEpoch = 4
@@ -774,15 +825,49 @@ func TestBeaconCommittees(t *testing.T) {

 	state, _ := util.DeterministicGenesisState(t, 256)

-	activeCount, err := helpers.ActiveValidatorCount(context.Background(), state, 0)
+	activeCount, err := helpers.ActiveValidatorCount(ctx, state, 0)
 	require.NoError(t, err)
 	committeesPerSlot := helpers.SlotCommitteeCount(activeCount)
-	committees, err := helpers.BeaconCommittees(context.Background(), state, 0)
+	committees, err := helpers.BeaconCommittees(ctx, state, 0)
 	require.NoError(t, err)
 	require.Equal(t, committeesPerSlot, uint64(len(committees)))
 	for idx := primitives.CommitteeIndex(0); idx < primitives.CommitteeIndex(len(committees)); idx++ {
-		committee, err := helpers.BeaconCommitteeFromState(context.Background(), state, 0, idx)
+		committee, err := helpers.BeaconCommitteeFromState(ctx, state, 0, idx)
 		require.NoError(t, err)
-		require.DeepEqual(t, committees[idx], committee)
+		assert.DeepEqual(t, committees[idx], committee)
+	}
+}
+
+func TestBeaconCommitteesFromCache(t *testing.T) {
+	ctx := context.Background()
+
+	params.SetupTestConfigCleanup(t)
+	c := params.BeaconConfig().Copy()
+	c.MinGenesisActiveValidatorCount = 128
+	c.SlotsPerEpoch = 4
+	c.TargetCommitteeSize = 16
+	params.OverrideBeaconConfig(c)
+
+	state, _ := util.DeterministicGenesisState(t, 256)
+
+	activeCount, err := helpers.ActiveValidatorCount(ctx, state, 0)
+	require.NoError(t, err)
+	committeesPerSlot := helpers.SlotCommitteeCount(activeCount)
+	committees, err := helpers.BeaconCommittees(ctx, state, 0)
+	require.NoError(t, err)
+	require.Equal(t, committeesPerSlot, uint64(len(committees)))
+
+	helpers.ClearCache()
+	for idx := primitives.CommitteeIndex(0); idx < primitives.CommitteeIndex(len(committees)); idx++ {
+		committee, err := helpers.BeaconCommitteeFromCache(ctx, state, 0, idx)
+		require.NoError(t, err)
+		assert.Equal(t, 0, len(committee))
+	}
+
+	require.NoError(t, helpers.UpdateCommitteeCache(ctx, state, 0))
+	for idx := primitives.CommitteeIndex(0); idx < primitives.CommitteeIndex(len(committees)); idx++ {
+		committee, err := helpers.BeaconCommitteeFromCache(ctx, state, 0, idx)
+		require.NoError(t, err)
+		assert.DeepEqual(t, committees[idx], committee)
 	}
 }
--- a/beacon-chain/db/filters/BUILD.bazel
+++ b/beacon-chain/db/filters/BUILD.bazel
@@ -2,13 +2,19 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")

 go_library(
    name = "go_default_library",
-    srcs = ["filter.go"],
+    srcs = [
+        "errors.go",
+        "filter.go",
+    ],
    importpath = "github.com/prysmaticlabs/prysm/v5/beacon-chain/db/filters",
    visibility = [
        "//beacon-chain:__subpackages__",
        "//tools:__subpackages__",
    ],
-    deps = ["//consensus-types/primitives:go_default_library"],
+    deps = [
+        "//consensus-types/primitives:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
+    ],
 )

 go_test(
@@ -18,5 +24,6 @@ go_test(
    deps = [
        "//consensus-types/primitives:go_default_library",
        "//testing/assert:go_default_library",
+        "//testing/require:go_default_library",
    ],
 )
--- a/beacon-chain/db/filters/errors.go
+++ b/beacon-chain/db/filters/errors.go
@@ -0,0 +1,9 @@
+package filters
+
+import "errors"
+
+var (
+	ErrIncompatibleFilters = errors.New("combination of filters is not valid")
+	ErrNotSet              = errors.New("filter was not set")
+	ErrInvalidQuery        = errors.New("invalid query")
+)
--- a/beacon-chain/db/filters/filter.go
+++ b/beacon-chain/db/filters/filter.go
@@ -14,7 +14,10 @@
 //	}
 package filters

-import primitives "github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
+import (
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
+)

 // FilterType defines an enum which is used as the keys in a map that tracks
 // set attribute filters for data as part of the `FilterQuery` struct type.
@@ -45,10 +48,34 @@ const (
 	SlotStep
 )

+// SlotRoot is the slot and root of a single block.
+type SlotRoot struct {
+	Slot primitives.Slot
+	Root [32]byte
+}
+
+// AncestryQuery is a special query that describes a chain of blocks that satisfies the invariant of:
+// blocks[n].parent_root == blocks[n-1].root.
+type AncestryQuery struct {
+	// Slot of oldest to return.
+	Earliest primitives.Slot
+	// Descendent that all ancestors in chain must descend from.
+	Descendent SlotRoot
+	set        bool
+}
+
+func (aq AncestryQuery) Span() primitives.Slot {
+	if aq.Earliest > aq.Descendent.Slot {
+		return 0
+	}
+	return (aq.Descendent.Slot - aq.Earliest) + 1 // +1 to include upper bound
+}
+
 // QueryFilter defines a generic interface for type-asserting
 // specific filters to use in querying DB objects.
 type QueryFilter struct {
-	queries map[FilterType]interface{}
+	queries  map[FilterType]interface{}
+	ancestry AncestryQuery
 }

 // NewFilter instantiates a new QueryFilter type used to build filters for
@@ -132,3 +159,42 @@ func (q *QueryFilter) SetSlotStep(val uint64) *QueryFilter {
 	q.queries[SlotStep] = val
 	return q
 }
+
+// SimpleSlotRange returns the start and end slot of a query filter if it is a simple slot range query.
+// A simple slot range query is one where the filter only contains a start slot and an end slot.
+// If the query is not a simple slot range query, the bool return value will be false.
+func (q *QueryFilter) SimpleSlotRange() (primitives.Slot, primitives.Slot, bool) {
+	if len(q.queries) != 2 || q.queries[StartSlot] == nil || q.queries[EndSlot] == nil {
+		return 0, 0, false
+	}
+	start, ok := q.queries[StartSlot].(primitives.Slot)
+	if !ok {
+		return 0, 0, false
+	}
+	end, ok := q.queries[EndSlot].(primitives.Slot)
+	if !ok {
+		return 0, 0, false
+	}
+	return start, end, true
+}
+
+// SetAncestryQuery sets the filter to be an ancestryQuery. Note that this filter type is exclusive with
+// other filters, so call ing GetAncestryQuery will return an error if other values are set.
+func (q *QueryFilter) SetAncestryQuery(aq AncestryQuery) *QueryFilter {
+	aq.set = true
+	q.ancestry = aq
+	return q
+}
+
+func (q *QueryFilter) GetAncestryQuery() (AncestryQuery, error) {
+	if !q.ancestry.set {
+		return q.ancestry, ErrNotSet
+	}
+	if len(q.queries) > 0 {
+		return q.ancestry, errors.Wrap(ErrIncompatibleFilters, "AncestryQuery cannot be combined with other filters")
+	}
+	if q.ancestry.Earliest > q.ancestry.Descendent.Slot {
+		return q.ancestry, errors.Wrap(ErrInvalidQuery, "descendent slot must come after earliest slot")
+	}
+	return q.ancestry, nil
+}
--- a/beacon-chain/db/filters/filter_test.go
+++ b/beacon-chain/db/filters/filter_test.go
@@ -5,6 +5,7 @@ import (

 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v5/testing/assert"
+	"github.com/prysmaticlabs/prysm/v5/testing/require"
 )

 func TestQueryFilter_ChainsCorrectly(t *testing.T) {
@@ -28,3 +29,64 @@ func TestQueryFilter_ChainsCorrectly(t *testing.T) {
 		}
 	}
 }
+
+func TestSimpleSlotRange(t *testing.T) {
+	type tc struct {
+		name        string
+		applFilters []func(*QueryFilter) *QueryFilter
+		isSimple    bool
+		start       primitives.Slot
+		end         primitives.Slot
+	}
+	cases := []tc{
+		{
+			name:        "no filters",
+			applFilters: []func(*QueryFilter) *QueryFilter{},
+			isSimple:    false,
+		},
+		{
+			name: "start slot",
+			applFilters: []func(*QueryFilter) *QueryFilter{
+				func(f *QueryFilter) *QueryFilter {
+					return f.SetStartSlot(3)
+				},
+			},
+			isSimple: false,
+		},
+		{
+			name: "end slot",
+			applFilters: []func(*QueryFilter) *QueryFilter{
+				func(f *QueryFilter) *QueryFilter {
+					return f.SetEndSlot(3)
+				},
+			},
+			isSimple: false,
+		},
+		{
+			name: "end slot",
+			applFilters: []func(*QueryFilter) *QueryFilter{
+				func(f *QueryFilter) *QueryFilter {
+					return f.SetStartSlot(3)
+				},
+				func(f *QueryFilter) *QueryFilter {
+					return f.SetEndSlot(7)
+				},
+			},
+			start:    3,
+			end:      7,
+			isSimple: true,
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			f := NewFilter()
+			for _, filt := range c.applFilters {
+				f = filt(f)
+			}
+			start, end, isSimple := f.SimpleSlotRange()
+			require.Equal(t, c.isSimple, isSimple)
+			require.Equal(t, c.start, start)
+			require.Equal(t, c.end, end)
+		})
+	}
+}
--- a/beacon-chain/db/iface/interface.go
+++ b/beacon-chain/db/iface/interface.go
@@ -101,7 +101,7 @@ type NoHeadAccessDatabase interface {
 	SaveLightClientBootstrap(ctx context.Context, blockRoot []byte, bootstrap interfaces.LightClientBootstrap) error

 	CleanUpDirtyStates(ctx context.Context, slotsPerArchivedPoint primitives.Slot) error
-	DeleteHistoricalDataBeforeSlot(ctx context.Context, slot primitives.Slot) error
+	DeleteHistoricalDataBeforeSlot(ctx context.Context, slot primitives.Slot, batchSize int) (int, error)
 }

 // HeadAccessDatabase defines a struct with access to reading chain head data.
@@ -110,6 +110,7 @@ type HeadAccessDatabase interface {

 	// Block related methods.
 	HeadBlock(ctx context.Context) (interfaces.ReadOnlySignedBeaconBlock, error)
+	HeadBlockRoot() ([32]byte, error)
 	SaveHeadBlockRoot(ctx context.Context, blockRoot [32]byte) error

 	// Genesis operations.
--- a/beacon-chain/db/kv/archived_point.go
+++ b/beacon-chain/db/kv/archived_point.go
@@ -35,7 +35,7 @@ func (s *Store) LastArchivedRoot(ctx context.Context) [32]byte {
 		_, blockRoot = bkt.Cursor().Last()
 		return nil
 	}); err != nil { // This view never returns an error, but we'll handle anyway for sanity.
-		panic(err)
+		panic(err) // lint:nopanic -- View never returns an error.
 	}

 	return bytesutil.ToBytes32(blockRoot)
@@ -53,7 +53,7 @@ func (s *Store) ArchivedPointRoot(ctx context.Context, slot primitives.Slot) [32
 		blockRoot = bucket.Get(bytesutil.SlotToBytesBigEndian(slot))
 		return nil
 	}); err != nil { // This view never returns an error, but we'll handle anyway for sanity.
-		panic(err)
+		panic(err) // lint:nopanic -- View never returns an error.
 	}

 	return bytesutil.ToBytes32(blockRoot)
@@ -69,7 +69,7 @@ func (s *Store) HasArchivedPoint(ctx context.Context, slot primitives.Slot) bool
 		exists = iBucket.Get(bytesutil.SlotToBytesBigEndian(slot)) != nil
 		return nil
 	}); err != nil { // This view never returns an error, but we'll handle anyway for sanity.
-		panic(err)
+		panic(err) // lint:nopanic -- View never returns an error.
 	}
 	return exists
 }
--- a/beacon-chain/db/kv/blocks.go
+++ b/beacon-chain/db/kv/blocks.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"slices"

 	"github.com/ethereum/go-ethereum/common"
 	"github.com/golang/snappy"
@@ -30,22 +31,32 @@ var errInvalidSlotRange = errors.New("invalid end slot and start slot provided")
 func (s *Store) Block(ctx context.Context, blockRoot [32]byte) (interfaces.ReadOnlySignedBeaconBlock, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.Block")
 	defer span.End()
-	// Return block from cache if it exists.
+	blk, err := s.getBlock(ctx, blockRoot, nil)
+	if errors.Is(err, ErrNotFound) {
+		return nil, nil
+	}
+	return blk, err
+}
+
+func (s *Store) getBlock(ctx context.Context, blockRoot [32]byte, tx *bolt.Tx) (interfaces.ReadOnlySignedBeaconBlock, error) {
 	if v, ok := s.blockCache.Get(string(blockRoot[:])); v != nil && ok {
 		return v.(interfaces.ReadOnlySignedBeaconBlock), nil
 	}
-	var blk interfaces.ReadOnlySignedBeaconBlock
-	err := s.db.View(func(tx *bolt.Tx) error {
-		bkt := tx.Bucket(blocksBucket)
-		enc := bkt.Get(blockRoot[:])
-		if enc == nil {
-			return nil
-		}
+	// This method allows the caller to pass in its tx if one is already open.
+	// Or if a nil value is used, a transaction will be managed intenally.
+	if tx == nil {
 		var err error
-		blk, err = unmarshalBlock(ctx, enc)
-		return err
-	})
-	return blk, err
+		tx, err = s.db.Begin(false)
+		if err != nil {
+			return nil, err
+		}
+		defer func() {
+			if err := tx.Rollback(); err != nil {
+				log.WithError(err).Error("could not rollback read-only getBlock transaction")
+			}
+		}()
+	}
+	return unmarshalBlock(ctx, tx.Bucket(blocksBucket).Get(blockRoot[:]))
 }

 // OriginCheckpointBlockRoot returns the value written to the db in SaveOriginCheckpointBlockRoot
@@ -70,6 +81,21 @@ func (s *Store) OriginCheckpointBlockRoot(ctx context.Context) ([32]byte, error)
 	return root, err
 }

+// HeadBlockRoot returns the latest canonical block root in the Ethereum Beacon Chain.
+func (s *Store) HeadBlockRoot() ([32]byte, error) {
+	var root [32]byte
+	err := s.db.View(func(tx *bolt.Tx) error {
+		bkt := tx.Bucket(blocksBucket)
+		headRoot := bkt.Get(headBlockRootKey)
+		if len(headRoot) == 0 {
+			return errors.New("no head block root found")
+		}
+		copy(root[:], headRoot)
+		return nil
+	})
+	return root, err
+}
+
 // HeadBlock returns the latest canonical block in the Ethereum Beacon Chain.
 func (s *Store) HeadBlock(ctx context.Context) (interfaces.ReadOnlySignedBeaconBlock, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.HeadBlock")
@@ -92,13 +118,95 @@ func (s *Store) HeadBlock(ctx context.Context) (interfaces.ReadOnlySignedBeaconB
 	return headBlock, err
 }

+// blocksAncestryQuery returns all blocks *before* the descendent block;
+// that is: inclusive of q.Earliest, exclusive of q.Descendent.Slot.
+func (s *Store) blocksAncestryQuery(ctx context.Context, q filters.AncestryQuery) ([]interfaces.ReadOnlySignedBeaconBlock, [][32]byte, error) {
+	// Save resources if no blocks will be found by the query.
+	if q.Span() < 1 {
+		return nil, nil, filters.ErrInvalidQuery
+	}
+
+	blocks := make([]interfaces.ReadOnlySignedBeaconBlock, 0, q.Span())
+	roots := make([][32]byte, 0, q.Span())
+	// Handle edge case where start and end are equal; slotRootsInRange would see end < start and err.
+	// So, just grab the descendent in its own tx and stop there.
+	if q.Span() == 1 {
+		err := s.db.View(func(tx *bolt.Tx) error {
+			descendent, err := s.getBlock(ctx, q.Descendent.Root, tx)
+			if err != nil {
+				return errors.Wrap(err, "descendent block not in db")
+			}
+			blocks = append(blocks, descendent)
+			roots = append(roots, q.Descendent.Root)
+			return nil
+		})
+		return blocks, roots, err
+	}
+
+	// stop before the descendent slot since it is determined by the query
+	sr, err := s.slotRootsInRange(ctx, q.Earliest, q.Descendent.Slot-1, -1)
+	if err != nil {
+		return nil, nil, err
+	}
+	err = s.db.View(func(tx *bolt.Tx) error {
+		descendent, err := s.getBlock(ctx, q.Descendent.Root, tx)
+		if err != nil {
+			return errors.Wrap(err, "descendent block not in db")
+		}
+		proot := descendent.Block().ParentRoot()
+		lowest := descendent.Block().Slot()
+		blocks = append(blocks, descendent)
+		roots = append(roots, q.Descendent.Root)
+		// slotRootsInRange returns the roots in descending order
+		for _, prev := range sr {
+			if prev.slot < q.Earliest {
+				return nil
+			}
+			if prev.slot >= lowest {
+				continue
+			}
+			if prev.root == proot {
+				p, err := s.getBlock(ctx, prev.root, tx)
+				if err != nil {
+					return err
+				}
+				roots = append(roots, prev.root)
+				blocks = append(blocks, p)
+				proot = p.Block().ParentRoot()
+				lowest = p.Block().Slot()
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+	slices.Reverse(roots)
+	slices.Reverse(blocks)
+
+	return blocks, roots, err
+}
+
 // Blocks retrieves a list of beacon blocks and its respective roots by filter criteria.
 func (s *Store) Blocks(ctx context.Context, f *filters.QueryFilter) ([]interfaces.ReadOnlySignedBeaconBlock, [][32]byte, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.Blocks")
 	defer span.End()
+
+	if q, err := f.GetAncestryQuery(); err == nil {
+		return s.blocksAncestryQuery(ctx, q)
+	} else {
+		if !errors.Is(err, filters.ErrNotSet) {
+			return nil, nil, err
+		}
+	}
+
 	blocks := make([]interfaces.ReadOnlySignedBeaconBlock, 0)
 	blockRoots := make([][32]byte, 0)

+	if start, end, isSimple := f.SimpleSlotRange(); isSimple {
+		return s.blocksForSlotRange(ctx, start, end)
+	}
+
 	err := s.db.View(func(tx *bolt.Tx) error {
 		bkt := tx.Bucket(blocksBucket)

@@ -121,6 +229,69 @@ func (s *Store) Blocks(ctx context.Context, f *filters.QueryFilter) ([]interface
 	return blocks, blockRoots, err
 }

+// cleanupMissingBlockIndices cleans up the slot->root mapping, and the parent root index pointing
+// from each of these blocks to each of their children. Since we don't have the blocks themselves,
+// we don't know their parent root to efficiently clean the index going the other direction.
+func (s *Store) cleanupMissingBlockIndices(ctx context.Context, badBlocks []slotRoot) {
+	errs := make([]error, 0)
+	err := s.db.Update(func(tx *bolt.Tx) error {
+		for _, sr := range badBlocks {
+			log.WithField("root", fmt.Sprintf("%#x", sr.root)).WithField("slot", sr.slot).Warn("Cleaning up indices for missing block")
+			if err := s.deleteSlotIndexEntry(tx, sr.slot, sr.root); err != nil {
+				errs = append(errs, errors.Wrapf(err, "failed to clean up slot index entry for root %#x and slot %d", sr.root, sr.slot))
+			}
+			if err := tx.Bucket(blockParentRootIndicesBucket).Delete(sr.root[:]); err != nil {
+				errs = append(errs, errors.Wrapf(err, "failed to clean up block parent index for root %#x", sr.root))
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		errs = append(errs, err)
+	}
+	for _, err := range errs {
+		log.WithError(err).Error("Failed to clean up indices for missing block")
+	}
+}
+
+// blocksForSlotRange gets all blocks and roots for a given slot range.
+// This function uses the slot->root index, which can contain multiple entries for the same slot
+// in case of forks. It will return all blocks for the given slot range, and the roots of those blocks.
+// The [i]th element of the blocks slice corresponds to the [i]th element of the roots slice.
+// If a block is not found, it will be added to a slice of missing blocks, which will have their indices cleaned
+// in a separate Update transaction before the method returns. This is done to compensate for a previous bug where
+// block deletions left danging index entries.
+func (s *Store) blocksForSlotRange(ctx context.Context, startSlot, endSlot primitives.Slot) ([]interfaces.ReadOnlySignedBeaconBlock, [][32]byte, error) {
+	slotRootPairs, err := s.slotRootsInRange(ctx, startSlot, endSlot, -1) // set batch size to zero to retrieve all
+	if err != nil {
+		return nil, nil, err
+	}
+	slices.Reverse(slotRootPairs)
+	badBlocks := make([]slotRoot, 0)
+	defer func() { s.cleanupMissingBlockIndices(ctx, badBlocks) }()
+	roots := make([][32]byte, 0, len(slotRootPairs))
+	blks := make([]interfaces.ReadOnlySignedBeaconBlock, 0, len(slotRootPairs))
+	err = s.db.View(func(tx *bolt.Tx) error {
+		for _, sr := range slotRootPairs {
+			blk, err := s.getBlock(ctx, sr.root, tx)
+			if err != nil {
+				if errors.Is(err, ErrNotFound) {
+					badBlocks = append(badBlocks, sr)
+					continue
+				}
+				return err
+			}
+			roots = append(roots, sr.root)
+			blks = append(blks, blk)
+		}
+		return nil
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+	return blks, roots, nil
+}
+
 // BlockRoots retrieves a list of beacon block roots by filter criteria. If the caller
 // requires both the blocks and the block roots for a certain filter they should instead
 // use the Blocks function rather than use BlockRoots. During periods of non finality
@@ -160,7 +331,7 @@ func (s *Store) HasBlock(ctx context.Context, blockRoot [32]byte) bool {
 		exists = bkt.Get(blockRoot[:]) != nil
 		return nil
 	}); err != nil { // This view never returns an error, but we'll handle anyway for sanity.
-		panic(err)
+		panic(err) // lint:nopanic -- View never returns an error.
 	}
 	return exists
 }
@@ -227,6 +398,21 @@ func (s *Store) DeleteBlock(ctx context.Context, root [32]byte) error {
 			return ErrDeleteJustifiedAndFinalized
 		}

+		// Look up the block to find its slot; needed to remove the slot index entry.
+		blk, err := s.getBlock(ctx, root, tx)
+		if err != nil {
+			// getBlock can return ErrNotFound, in which case we won't even try to delete it.
+			if errors.Is(err, ErrNotFound) {
+				return nil
+			}
+			return err
+		}
+		if err := s.deleteSlotIndexEntry(tx, blk.Block().Slot(), root); err != nil {
+			return err
+		}
+		if err := s.deleteMatchingParentIndex(tx, blk.Block().ParentRoot(), root); err != nil {
+			return err
+		}
 		if err := s.deleteBlock(tx, root[:]); err != nil {
 			return err
 		}
@@ -245,77 +431,82 @@ func (s *Store) DeleteBlock(ctx context.Context, root [32]byte) error {
 // - blockRootValidatorHashesBucket
 // - blockSlotIndicesBucket
 // - stateSlotIndicesBucket
-func (s *Store) DeleteHistoricalDataBeforeSlot(ctx context.Context, cutoffSlot primitives.Slot) error {
+func (s *Store) DeleteHistoricalDataBeforeSlot(ctx context.Context, cutoffSlot primitives.Slot, batchSize int) (int, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.DeleteHistoricalDataBeforeSlot")
 	defer span.End()

 	// Collect slot/root pairs to perform deletions in a separate read only transaction.
-	var (
-		roots [][]byte
-		slts  []primitives.Slot
-	)
-	err := s.db.View(func(tx *bolt.Tx) error {
-		var err error
-		roots, slts, err = blockRootsBySlotRange(ctx, tx.Bucket(blockSlotIndicesBucket), primitives.Slot(0), cutoffSlot, nil, nil, nil)
-		if err != nil {
-			return errors.Wrap(err, "could not retrieve block roots")
-		}
-		return nil
-	})
+	slotRoots, err := s.slotRootsInRange(ctx, primitives.Slot(0), cutoffSlot, batchSize)
 	if err != nil {
-		return errors.Wrap(err, "could not retrieve block roots and slots")
+		return 0, err
+	}
+
+	// Return early if there's nothing to delete.
+	if len(slotRoots) == 0 {
+		return 0, nil
 	}

 	// Perform all deletions in a single transaction for atomicity
-	return s.db.Update(func(tx *bolt.Tx) error {
-		for _, root := range roots {
+	var numSlotsDeleted int
+	err = s.db.Update(func(tx *bolt.Tx) error {
+		for _, sr := range slotRoots {
+			// Return if context is cancelled or deadline is exceeded.
+			if ctx.Err() != nil {
+				//nolint:nilerr
+				return nil
+			}
+
 			// Delete block
-			if err = s.deleteBlock(tx, root); err != nil {
+			if err = s.deleteBlock(tx, sr.root[:]); err != nil {
 				return err
 			}

 			// Delete finalized block roots index
-			if err = tx.Bucket(finalizedBlockRootsIndexBucket).Delete(root); err != nil {
+			if err = tx.Bucket(finalizedBlockRootsIndexBucket).Delete(sr.root[:]); err != nil {
 				return errors.Wrap(err, "could not delete finalized block root index")
 			}

 			// Delete state
-			if err = tx.Bucket(stateBucket).Delete(root); err != nil {
+			if err = tx.Bucket(stateBucket).Delete(sr.root[:]); err != nil {
 				return errors.Wrap(err, "could not delete state")
 			}

 			// Delete state summary
-			if err = tx.Bucket(stateSummaryBucket).Delete(root); err != nil {
+			if err = tx.Bucket(stateSummaryBucket).Delete(sr.root[:]); err != nil {
 				return errors.Wrap(err, "could not delete state summary")
 			}

 			// Delete validator entries
-			if err = s.deleteValidatorHashes(tx, root); err != nil {
+			if err = s.deleteValidatorHashes(tx, sr.root[:]); err != nil {
 				return errors.Wrap(err, "could not delete validators")
 			}
+
+			numSlotsDeleted++
 		}

-		for _, slot := range slts {
+		for _, sr := range slotRoots {
 			// Delete slot indices
-			if err = tx.Bucket(blockSlotIndicesBucket).Delete(bytesutil.SlotToBytesBigEndian(slot)); err != nil {
+			if err = tx.Bucket(blockSlotIndicesBucket).Delete(bytesutil.SlotToBytesBigEndian(sr.slot)); err != nil {
 				return errors.Wrap(err, "could not delete block slot index")
 			}
-			if err = tx.Bucket(stateSlotIndicesBucket).Delete(bytesutil.SlotToBytesBigEndian(slot)); err != nil {
+			if err = tx.Bucket(stateSlotIndicesBucket).Delete(bytesutil.SlotToBytesBigEndian(sr.slot)); err != nil {
 				return errors.Wrap(err, "could not delete state slot index")
 			}
 		}

 		// Delete all caches after we have deleted everything from buckets.
 		// This is done after the buckets are deleted to avoid any issues in case of transaction rollback.
-		for _, root := range roots {
+		for _, sr := range slotRoots {
 			// Delete block from cache
-			s.blockCache.Del(string(root))
+			s.blockCache.Del(string(sr.root[:]))
 			// Delete state summary from cache
-			s.stateSummaryCache.delete([32]byte(root))
+			s.stateSummaryCache.delete(sr.root)
 		}

 		return nil
 	})
+
+	return numSlotsDeleted, err
 }

 // SaveBlock to the db.
@@ -336,7 +527,7 @@ func (s *Store) SaveBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 // if a `saveBlindedBeaconBlocks` key exists in the database. Otherwise, we check if the last
 // blocked stored to check if it is blinded, and then write that `saveBlindedBeaconBlocks` key
 // to the DB for future checks.
-func (s *Store) shouldSaveBlinded(ctx context.Context) (bool, error) {
+func (s *Store) shouldSaveBlinded() (bool, error) {
 	var saveBlinded bool
 	if err := s.db.View(func(tx *bolt.Tx) error {
 		metadataBkt := tx.Bucket(chainMetadataBucket)
@@ -398,7 +589,7 @@ func prepareBlockBatch(blks []blocks.ROBlock, shouldBlind bool) ([]blockBatchEnt
 }

 func (s *Store) SaveROBlocks(ctx context.Context, blks []blocks.ROBlock, cache bool) error {
-	shouldBlind, err := s.shouldSaveBlinded(ctx)
+	shouldBlind, err := s.shouldSaveBlinded()
 	if err != nil {
 		return err
 	}
@@ -669,6 +860,68 @@ func (s *Store) SaveRegistrationsByValidatorIDs(ctx context.Context, ids []primi
 	})
 }

+type slotRoot struct {
+	slot primitives.Slot
+	root [32]byte
+}
+
+// slotRootsInRange returns slot and block root pairs of length min(batchSize, end-slot)
+// If batchSize < 0, the limit check will be skipped entirely.
+func (s *Store) slotRootsInRange(ctx context.Context, start, end primitives.Slot, batchSize int) ([]slotRoot, error) {
+	_, span := trace.StartSpan(ctx, "BeaconDB.slotRootsInRange")
+	defer span.End()
+	if end < start {
+		return nil, errInvalidSlotRange
+	}
+
+	var pairs []slotRoot
+	key := bytesutil.SlotToBytesBigEndian(end)
+
+	edge := false // used to detect whether we are at the very beginning or end of the index
+	err := s.db.View(func(tx *bolt.Tx) error {
+		bkt := tx.Bucket(blockSlotIndicesBucket)
+		c := bkt.Cursor()
+		for k, v := c.Seek(key); ; /* rely on internal checks to exit */ k, v = c.Prev() {
+			if len(k) == 0 && len(v) == 0 {
+				// The `edge`` variable and this `if` deal with 2 edge cases:
+				// - Seeking past the end of the bucket (the `end` param is higher than the highest slot).
+				// - Seeking before the beginning of the bucket (the `start` param is lower than the lowest slot).
+				// In both of these cases k,v will be nil and we can handle the same way using `edge` to
+				// - continue to the next iteration. If the following Prev() key/value is nil, Prev has gone past the beginning.
+				// - Otherwise, iterate as usual.
+				if edge {
+					return nil
+				}
+				edge = true
+				continue
+			}
+			edge = false
+			slot := bytesutil.BytesToSlotBigEndian(k)
+			if slot > end {
+				continue // Seek will seek to the next key *after* the given one if not present
+			}
+			if slot < start {
+				return nil
+			}
+			roots, err := splitRoots(v)
+			if err != nil {
+				return errors.Wrapf(err, "corrupt value %v in block slot index for slot=%d", v, slot)
+			}
+			for _, r := range roots {
+				pairs = append(pairs, slotRoot{slot: slot, root: r})
+			}
+			if batchSize < 0 {
+				continue
+			}
+			if len(pairs) >= batchSize {
+				return nil // allows code to easily cap the number of items pruned
+			}
+		}
+	})
+
+	return pairs, err
+}
+
 // blockRootsByFilter retrieves the block roots given the filter criteria.
 func blockRootsByFilter(ctx context.Context, tx *bolt.Tx, f *filters.QueryFilter) ([][]byte, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.blockRootsByFilter")
@@ -689,7 +942,7 @@ func blockRootsByFilter(ctx context.Context, tx *bolt.Tx, f *filters.QueryFilter

 	// We retrieve block roots that match a filter criteria of slot ranges, if specified.
 	filtersMap := f.Filters()
-	rootsBySlotRange, _, err := blockRootsBySlotRange(
+	rootsBySlotRange, err := blockRootsBySlotRange(
 		ctx,
 		tx.Bucket(blockSlotIndicesBucket),
 		filtersMap[filters.StartSlot],
@@ -734,13 +987,13 @@ func blockRootsBySlotRange(
 	ctx context.Context,
 	bkt *bolt.Bucket,
 	startSlotEncoded, endSlotEncoded, startEpochEncoded, endEpochEncoded, slotStepEncoded interface{},
-) ([][]byte, []primitives.Slot, error) {
+) ([][]byte, error) {
 	_, span := trace.StartSpan(ctx, "BeaconDB.blockRootsBySlotRange")
 	defer span.End()

 	// Return nothing when all slot parameters are missing
 	if startSlotEncoded == nil && endSlotEncoded == nil && startEpochEncoded == nil && endEpochEncoded == nil {
-		return [][]byte{}, nil, nil
+		return [][]byte{}, nil
 	}

 	var startSlot, endSlot primitives.Slot
@@ -761,11 +1014,11 @@ func blockRootsBySlotRange(
 	if startEpochOk && endEpochOk {
 		startSlot, err = slots.EpochStart(startEpoch)
 		if err != nil {
-			return nil, nil, err
+			return nil, err
 		}
 		endSlot, err = slots.EpochStart(endEpoch)
 		if err != nil {
-			return nil, nil, err
+			return nil, err
 		}
 		endSlot = endSlot + params.BeaconConfig().SlotsPerEpoch - 1
 	}
@@ -776,11 +1029,10 @@ func blockRootsBySlotRange(
 		return key != nil && bytes.Compare(key, max) <= 0
 	}
 	if endSlot < startSlot {
-		return nil, nil, errInvalidSlotRange
+		return nil, errInvalidSlotRange
 	}
 	rootsRange := endSlot.SubSlot(startSlot).Div(step)
 	roots := make([][]byte, 0, rootsRange)
-	var slts []primitives.Slot
 	c := bkt.Cursor()
 	for k, v := c.Seek(min); conditional(k, max); k, v = c.Next() {
 		slot := bytesutil.BytesToSlotBigEndian(k)
@@ -795,9 +1047,8 @@ func blockRootsBySlotRange(
 			splitRoots = append(splitRoots, v[i:i+32])
 		}
 		roots = append(roots, splitRoots...)
-		slts = append(slts, slot)
 	}
-	return roots, slts, nil
+	return roots, nil
 }

 // blockRootsBySlot retrieves the block roots by slot
@@ -853,6 +1104,9 @@ func createBlockIndicesFromFilters(ctx context.Context, f *filters.QueryFilter)

 // unmarshal block from marshaled proto beacon block bytes to versioned beacon block struct type.
 func unmarshalBlock(_ context.Context, enc []byte) (interfaces.ReadOnlySignedBeaconBlock, error) {
+	if len(enc) == 0 {
+		return nil, errors.Wrap(ErrNotFound, "empty block bytes in db")
+	}
 	var err error
 	enc, err = snappy.Decode(nil, enc)
 	if err != nil {
@@ -1004,6 +1258,47 @@ func (s *Store) deleteBlock(tx *bolt.Tx, root []byte) error {
 	return nil
 }

+func (s *Store) deleteMatchingParentIndex(tx *bolt.Tx, parent, child [32]byte) error {
+	bkt := tx.Bucket(blockParentRootIndicesBucket)
+	if err := deleteRootIndexEntry(bkt, parent[:], child); err != nil {
+		return errors.Wrap(err, "could not delete parent root index entry")
+	}
+	return nil
+}
+
+func (s *Store) deleteSlotIndexEntry(tx *bolt.Tx, slot primitives.Slot, root [32]byte) error {
+	key := bytesutil.SlotToBytesBigEndian(slot)
+	bkt := tx.Bucket(blockSlotIndicesBucket)
+	if err := deleteRootIndexEntry(bkt, key, root); err != nil {
+		return errors.Wrap(err, "could not delete slot index entry")
+	}
+	return nil
+}
+
+func deleteRootIndexEntry(bkt *bolt.Bucket, key []byte, root [32]byte) error {
+	packed := bkt.Get(key)
+	if len(packed) == 0 {
+		return nil
+	}
+	updated, err := removeRoot(packed, root)
+	if err != nil {
+		return err
+	}
+	// Don't update the value if the root was not found.
+	if bytes.Equal(updated, packed) {
+		return nil
+	}
+	// If there are no other roots in the key, just delete it.
+	if len(updated) == 0 {
+		if err := bkt.Delete(key); err != nil {
+			return err
+		}
+		return nil
+	}
+	// Update the key with the root removed.
+	return bkt.Put(key, updated)
+}
+
 func (s *Store) deleteValidatorHashes(tx *bolt.Tx, root []byte) error {
 	ok, err := s.isStateValidatorMigrationOver()
 	if err != nil {
--- a/beacon-chain/db/kv/blocks_test.go
+++ b/beacon-chain/db/kv/blocks_test.go
@@ -24,9 +24,11 @@ import (
 	"google.golang.org/protobuf/proto"
 )

+type testNewBlockFunc func(primitives.Slot, []byte) (interfaces.ReadOnlySignedBeaconBlock, error)
+
 var blockTests = []struct {
 	name     string
-	newBlock func(primitives.Slot, []byte) (interfaces.ReadOnlySignedBeaconBlock, error)
+	newBlock testNewBlockFunc
 }{
 	{
 		name: "phase0",
@@ -196,9 +198,13 @@ func TestStore_BlocksCRUD(t *testing.T) {
 			blockRoot, err := blk.Block().HashTreeRoot()
 			require.NoError(t, err)

+			_, err = db.getBlock(ctx, blockRoot, nil)
+			require.ErrorIs(t, err, ErrNotFound)
 			retrievedBlock, err := db.Block(ctx, blockRoot)
 			require.NoError(t, err)
 			assert.DeepEqual(t, nil, retrievedBlock, "Expected nil block")
+			_, err = db.getBlock(ctx, blockRoot, nil)
+			require.ErrorIs(t, err, ErrNotFound)

 			require.NoError(t, db.SaveBlock(ctx, blk))
 			assert.Equal(t, true, db.HasBlock(ctx, blockRoot), "Expected block to exist in the db")
@@ -214,10 +220,34 @@ func TestStore_BlocksCRUD(t *testing.T) {
 			retrievedPb, err := retrievedBlock.Proto()
 			require.NoError(t, err)
 			assert.Equal(t, true, proto.Equal(wantedPb, retrievedPb), "Wanted: %v, received: %v", wanted, retrievedBlock)
+			// Check that the block is in the slot->block index
+			found, roots, err := db.BlockRootsBySlot(ctx, blk.Block().Slot())
+			require.NoError(t, err)
+			require.Equal(t, true, found)
+			require.Equal(t, 1, len(roots))
+			require.Equal(t, blockRoot, roots[0])
+			// Delete the block, then check that it is no longer in the index.
+
+			parent := blk.Block().ParentRoot()
+			testCheckParentIndices(t, db.db, parent, true)
+			require.NoError(t, db.DeleteBlock(ctx, blockRoot))
+			require.NoError(t, err)
+			testCheckParentIndices(t, db.db, parent, false)
+			found, roots, err = db.BlockRootsBySlot(ctx, blk.Block().Slot())
+			require.NoError(t, err)
+			require.Equal(t, false, found)
+			require.Equal(t, 0, len(roots))
 		})
 	}
 }

+func testCheckParentIndices(t *testing.T, db *bolt.DB, parent [32]byte, expected bool) {
+	require.NoError(t, db.View(func(tx *bolt.Tx) error {
+		require.Equal(t, expected, tx.Bucket(blockParentRootIndicesBucket).Get(parent[:]) != nil)
+		return nil
+	}))
+}
+
 func TestStore_BlocksHandleZeroCase(t *testing.T) {
 	for _, tt := range blockTests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -359,184 +389,221 @@ func TestStore_DeleteFinalizedBlock(t *testing.T) {

 func TestStore_HistoricalDataBeforeSlot(t *testing.T) {
 	slotsPerEpoch := uint64(params.BeaconConfig().SlotsPerEpoch)
-	db := setupDB(t)
 	ctx := context.Background()

-	// Save genesis block root
-	require.NoError(t, db.SaveGenesisBlockRoot(ctx, genesisBlockRoot))
+	tests := []struct {
+		name             string
+		batchSize        int
+		numOfEpochs      uint64
+		deleteBeforeSlot uint64
+	}{
+		{
+			name:             "batchSize less than delete range",
+			batchSize:        10,
+			numOfEpochs:      4,
+			deleteBeforeSlot: 25,
+		},
+		{
+			name:             "batchSize greater than delete range",
+			batchSize:        30,
+			numOfEpochs:      4,
+			deleteBeforeSlot: 15,
+		},
+	}

-	// Create and save blocks for 4 epochs
-	blks := makeBlocks(t, 0, slotsPerEpoch*4, genesisBlockRoot)
-	require.NoError(t, db.SaveBlocks(ctx, blks))
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			db := setupDB(t)
+			// Save genesis block root
+			require.NoError(t, db.SaveGenesisBlockRoot(ctx, genesisBlockRoot))

-	// Mark state validator migration as complete
-	err := db.db.Update(func(tx *bolt.Tx) error {
-		return tx.Bucket(migrationsBucket).Put(migrationStateValidatorsKey, migrationCompleted)
-	})
-	require.NoError(t, err)
+			// Create and save blocks for given epochs
+			blks := makeBlocks(t, 0, slotsPerEpoch*tt.numOfEpochs, genesisBlockRoot)
+			require.NoError(t, db.SaveBlocks(ctx, blks))

-	migrated, err := db.isStateValidatorMigrationOver()
-	require.NoError(t, err)
-	require.Equal(t, true, migrated)
+			// Mark state validator migration as complete
+			err := db.db.Update(func(tx *bolt.Tx) error {
+				return tx.Bucket(migrationsBucket).Put(migrationStateValidatorsKey, migrationCompleted)
+			})
+			require.NoError(t, err)

-	// Create state summaries and states for each block
-	ss := make([]*ethpb.StateSummary, len(blks))
-	states := make([]state.BeaconState, len(blks))
+			migrated, err := db.isStateValidatorMigrationOver()
+			require.NoError(t, err)
+			require.Equal(t, true, migrated)

-	for i, blk := range blks {
-		slot := blk.Block().Slot()
-		r, err := blk.Block().HashTreeRoot()
-		require.NoError(t, err)
+			// Create state summaries and states for each block
+			ss := make([]*ethpb.StateSummary, len(blks))
+			states := make([]state.BeaconState, len(blks))

-		// Create and save state summary
-		ss[i] = &ethpb.StateSummary{
-			Slot: slot,
-			Root: r[:],
-		}
+			for i, blk := range blks {
+				slot := blk.Block().Slot()
+				r, err := blk.Block().HashTreeRoot()
+				require.NoError(t, err)

-		// Create and save state with validator entries
-		vals := make([]*ethpb.Validator, 2)
-		for j := range vals {
-			vals[j] = &ethpb.Validator{
-				PublicKey:             bytesutil.PadTo([]byte{byte(i*j + 1)}, 48),
-				WithdrawalCredentials: bytesutil.PadTo([]byte{byte(i*j + 2)}, 32),
+				// Create and save state summary
+				ss[i] = &ethpb.StateSummary{
+					Slot: slot,
+					Root: r[:],
+				}
+
+				// Create and save state with validator entries
+				vals := make([]*ethpb.Validator, 2)
+				for j := range vals {
+					vals[j] = &ethpb.Validator{
+						PublicKey:             bytesutil.PadTo([]byte{byte(i*j + 1)}, 48),
+						WithdrawalCredentials: bytesutil.PadTo([]byte{byte(i*j + 2)}, 32),
+					}
+				}
+
+				st, err := util.NewBeaconState(func(state *ethpb.BeaconState) error {
+					state.Validators = vals
+					state.Slot = slot
+					return nil
+				})
+				require.NoError(t, err)
+				require.NoError(t, db.SaveState(ctx, st, r))
+				states[i] = st
+
+				// Verify validator entries are saved to db
+				valsActual, err := db.validatorEntries(ctx, r)
+				require.NoError(t, err)
+				for j, val := range valsActual {
+					require.DeepEqual(t, vals[j], val)
+				}
 			}
-		}
+			require.NoError(t, db.SaveStateSummaries(ctx, ss))

-		st, err := util.NewBeaconState(func(state *ethpb.BeaconState) error {
-			state.Validators = vals
-			state.Slot = slot
-			return nil
-		})
-		require.NoError(t, err)
-		require.NoError(t, db.SaveState(ctx, st, r))
-		states[i] = st
-
-		// Verify validator entries are saved to db
-		valsActual, err := db.validatorEntries(ctx, r)
-		require.NoError(t, err)
-		for j, val := range valsActual {
-			require.DeepEqual(t, vals[j], val)
-		}
-	}
-	require.NoError(t, db.SaveStateSummaries(ctx, ss))
-
-	// Verify slot indices exist before deletion
-	err = db.db.View(func(tx *bolt.Tx) error {
-		blockSlotBkt := tx.Bucket(blockSlotIndicesBucket)
-		stateSlotBkt := tx.Bucket(stateSlotIndicesBucket)
-
-		for i := uint64(0); i < slotsPerEpoch; i++ {
-			slot := bytesutil.SlotToBytesBigEndian(primitives.Slot(i + 1))
-			assert.NotNil(t, blockSlotBkt.Get(slot), "Expected block slot index to exist")
-			assert.NotNil(t, stateSlotBkt.Get(slot), "Expected state slot index to exist", i)
-		}
-		return nil
-	})
-	require.NoError(t, err)
-
-	// Delete data before slot at epoch 1
-	require.NoError(t, db.DeleteHistoricalDataBeforeSlot(ctx, primitives.Slot(slotsPerEpoch)))
-
-	// Verify blocks from epoch 0 are deleted
-	for i := uint64(0); i < slotsPerEpoch; i++ {
-		root, err := blks[i].Block().HashTreeRoot()
-		require.NoError(t, err)
-
-		// Check block is deleted
-		retrievedBlocks, err := db.BlocksBySlot(ctx, primitives.Slot(i))
-		require.NoError(t, err)
-		assert.Equal(t, 0, len(retrievedBlocks))
-
-		// Verify block does not exist
-		assert.Equal(t, false, db.HasBlock(ctx, root))
-
-		// Verify block parent root does not exist
-		err = db.db.View(func(tx *bolt.Tx) error {
-			require.Equal(t, 0, len(tx.Bucket(blockParentRootIndicesBucket).Get(root[:])))
-			return nil
-		})
-		require.NoError(t, err)
-
-		// Verify state is deleted
-		hasState := db.HasState(ctx, root)
-		assert.Equal(t, false, hasState)
-
-		// Verify state summary is deleted
-		hasSummary := db.HasStateSummary(ctx, root)
-		assert.Equal(t, false, hasSummary)
-
-		// Verify validator hashes for block roots are deleted
-		err = db.db.View(func(tx *bolt.Tx) error {
-			assert.Equal(t, 0, len(tx.Bucket(blockRootValidatorHashesBucket).Get(root[:])))
-			return nil
-		})
-		require.NoError(t, err)
-	}
-
-	// Verify slot indices are deleted
-	err = db.db.View(func(tx *bolt.Tx) error {
-		blockSlotBkt := tx.Bucket(blockSlotIndicesBucket)
-		stateSlotBkt := tx.Bucket(stateSlotIndicesBucket)
-
-		for i := uint64(0); i < slotsPerEpoch; i++ {
-			slot := bytesutil.SlotToBytesBigEndian(primitives.Slot(i + 1))
-			assert.Equal(t, 0, len(blockSlotBkt.Get(slot)), fmt.Sprintf("Expected block slot index to be deleted, slot: %d", slot))
-			assert.Equal(t, 0, len(stateSlotBkt.Get(slot)), fmt.Sprintf("Expected state slot index to be deleted, slot: %d", slot))
-		}
-		return nil
-	})
-	require.NoError(t, err)
-
-	// Verify blocks from epochs 1-3 still exist
-	for i := slotsPerEpoch; i < slotsPerEpoch*4; i++ {
-		root, err := blks[i].Block().HashTreeRoot()
-		require.NoError(t, err)
-
-		// Verify block exists
-		assert.Equal(t, true, db.HasBlock(ctx, root))
-
-		// Verify remaining block parent root exists, except last slot since we store parent roots of each block.
-		if i < slotsPerEpoch*4-1 {
+			// Verify slot indices exist before deletion
 			err = db.db.View(func(tx *bolt.Tx) error {
-				require.NotNil(t, tx.Bucket(blockParentRootIndicesBucket).Get(root[:]), fmt.Sprintf("Expected block parent index to be deleted, slot: %d", i))
+				blockSlotBkt := tx.Bucket(blockSlotIndicesBucket)
+				stateSlotBkt := tx.Bucket(stateSlotIndicesBucket)
+
+				for i := uint64(0); i < uint64(tt.deleteBeforeSlot); i++ {
+					slot := bytesutil.SlotToBytesBigEndian(primitives.Slot(i + 1))
+					assert.NotNil(t, blockSlotBkt.Get(slot), "Expected block slot index to exist")
+					assert.NotNil(t, stateSlotBkt.Get(slot), "Expected state slot index to exist", i)
+				}
 				return nil
 			})
 			require.NoError(t, err)
-		}

-		// Verify state exists
-		hasState := db.HasState(ctx, root)
-		assert.Equal(t, true, hasState)
+			// Delete data before slot
+			slotsDeleted, err := db.DeleteHistoricalDataBeforeSlot(ctx, primitives.Slot(tt.deleteBeforeSlot), tt.batchSize)
+			require.NoError(t, err)

-		// Verify state summary exists
-		hasSummary := db.HasStateSummary(ctx, root)
-		assert.Equal(t, true, hasSummary)
+			var startSlotDeleted, endSlotDeleted uint64
+			if tt.batchSize >= int(tt.deleteBeforeSlot) {
+				startSlotDeleted = 1
+				endSlotDeleted = tt.deleteBeforeSlot
+			} else {
+				startSlotDeleted = tt.deleteBeforeSlot - uint64(tt.batchSize) + 1
+				endSlotDeleted = tt.deleteBeforeSlot
+			}

-		// Verify slot indices still exist
-		err = db.db.View(func(tx *bolt.Tx) error {
-			blockSlotBkt := tx.Bucket(blockSlotIndicesBucket)
-			stateSlotBkt := tx.Bucket(stateSlotIndicesBucket)
+			require.Equal(t, endSlotDeleted-startSlotDeleted+1, uint64(slotsDeleted))

-			slot := bytesutil.SlotToBytesBigEndian(primitives.Slot(i + 1))
-			assert.NotNil(t, blockSlotBkt.Get(slot), "Expected block slot index to exist")
-			assert.NotNil(t, stateSlotBkt.Get(slot), "Expected state slot index to exist")
-			return nil
+			// Verify blocks before given slot/batch are deleted
+			for i := startSlotDeleted; i < endSlotDeleted; i++ {
+				root, err := blks[i].Block().HashTreeRoot()
+				require.NoError(t, err)
+
+				// Check block is deleted
+				retrievedBlocks, err := db.BlocksBySlot(ctx, primitives.Slot(i))
+				require.NoError(t, err)
+				assert.Equal(t, 0, len(retrievedBlocks), fmt.Sprintf("Expected %d blocks, got %d for slot %d", 0, len(retrievedBlocks), i))
+
+				// Verify block does not exist
+				assert.Equal(t, false, db.HasBlock(ctx, root), fmt.Sprintf("Expected block index to not exist for slot %d", i))
+
+				// Verify block parent root does not exist
+				err = db.db.View(func(tx *bolt.Tx) error {
+					require.Equal(t, 0, len(tx.Bucket(blockParentRootIndicesBucket).Get(root[:])))
+					return nil
+				})
+				require.NoError(t, err)
+
+				// Verify state is deleted
+				hasState := db.HasState(ctx, root)
+				assert.Equal(t, false, hasState)
+
+				// Verify state summary is deleted
+				hasSummary := db.HasStateSummary(ctx, root)
+				assert.Equal(t, false, hasSummary)
+
+				// Verify validator hashes for block roots are deleted
+				err = db.db.View(func(tx *bolt.Tx) error {
+					assert.Equal(t, 0, len(tx.Bucket(blockRootValidatorHashesBucket).Get(root[:])))
+					return nil
+				})
+				require.NoError(t, err)
+			}
+
+			// Verify slot indices are deleted
+			err = db.db.View(func(tx *bolt.Tx) error {
+				blockSlotBkt := tx.Bucket(blockSlotIndicesBucket)
+				stateSlotBkt := tx.Bucket(stateSlotIndicesBucket)
+
+				for i := startSlotDeleted; i < endSlotDeleted; i++ {
+					slot := bytesutil.SlotToBytesBigEndian(primitives.Slot(i + 1))
+					assert.Equal(t, 0, len(blockSlotBkt.Get(slot)), fmt.Sprintf("Expected block slot index to be deleted, slot: %d", slot))
+					assert.Equal(t, 0, len(stateSlotBkt.Get(slot)), fmt.Sprintf("Expected state slot index to be deleted, slot: %d", slot))
+				}
+				return nil
+			})
+			require.NoError(t, err)
+
+			// Verify blocks from expectedLastDeletedSlot till numEpochs still exist
+			for i := endSlotDeleted; i < slotsPerEpoch*tt.numOfEpochs; i++ {
+				root, err := blks[i].Block().HashTreeRoot()
+				require.NoError(t, err)
+
+				// Verify block exists
+				assert.Equal(t, true, db.HasBlock(ctx, root))
+
+				// Verify remaining block parent root exists, except last slot since we store parent roots of each block.
+				if i < slotsPerEpoch*tt.numOfEpochs-1 {
+					err = db.db.View(func(tx *bolt.Tx) error {
+						require.NotNil(t, tx.Bucket(blockParentRootIndicesBucket).Get(root[:]), fmt.Sprintf("Expected block parent index to be deleted, slot: %d", i))
+						return nil
+					})
+					require.NoError(t, err)
+				}
+
+				// Verify state exists
+				hasState := db.HasState(ctx, root)
+				assert.Equal(t, true, hasState)
+
+				// Verify state summary exists
+				hasSummary := db.HasStateSummary(ctx, root)
+				assert.Equal(t, true, hasSummary)
+
+				// Verify slot indices still exist
+				err = db.db.View(func(tx *bolt.Tx) error {
+					blockSlotBkt := tx.Bucket(blockSlotIndicesBucket)
+					stateSlotBkt := tx.Bucket(stateSlotIndicesBucket)
+
+					slot := bytesutil.SlotToBytesBigEndian(primitives.Slot(i + 1))
+					assert.NotNil(t, blockSlotBkt.Get(slot), "Expected block slot index to exist")
+					assert.NotNil(t, stateSlotBkt.Get(slot), "Expected state slot index to exist")
+					return nil
+				})
+				require.NoError(t, err)
+
+				// Verify validator entries still exist
+				valsActual, err := db.validatorEntries(ctx, root)
+				require.NoError(t, err)
+				assert.NotNil(t, valsActual)
+
+				// Verify remaining validator hashes for block roots exists
+				err = db.db.View(func(tx *bolt.Tx) error {
+					assert.NotNil(t, tx.Bucket(blockRootValidatorHashesBucket).Get(root[:]))
+					return nil
+				})
+				require.NoError(t, err)
+			}
 		})
-		require.NoError(t, err)
-
-		// Verify validator entries still exist
-		valsActual, err := db.validatorEntries(ctx, root)
-		require.NoError(t, err)
-		assert.NotNil(t, valsActual)
-
-		// Verify remaining validator hashes for block roots exists
-		err = db.db.View(func(tx *bolt.Tx) error {
-			assert.NotNil(t, tx.Bucket(blockRootValidatorHashesBucket).Get(root[:]))
-			return nil
-		})
-		require.NoError(t, err)
 	}
+
 }

 func TestStore_GenesisBlock(t *testing.T) {
@@ -677,6 +744,120 @@ func TestStore_Blocks_FiltersCorrectly(t *testing.T) {
 	}
 }

+func testBlockChain(t *testing.T, nb testNewBlockFunc, slots []primitives.Slot, parent []byte) []interfaces.ReadOnlySignedBeaconBlock {
+	if len(parent) < 32 {
+		var zero [32]byte
+		copy(parent, zero[:])
+	}
+	chain := make([]interfaces.ReadOnlySignedBeaconBlock, 0, len(slots))
+	for _, slot := range slots {
+		pr := make([]byte, 32)
+		copy(pr, parent)
+		b, err := nb(slot, pr)
+		require.NoError(t, err)
+		chain = append(chain, b)
+		npr, err := b.Block().HashTreeRoot()
+		parent = npr[:]
+		require.NoError(t, err)
+	}
+	return chain
+}
+
+func testSlotSlice(start, end primitives.Slot) []primitives.Slot {
+	end += 1 // add 1 to make the range inclusive
+	slots := make([]primitives.Slot, 0, end-start)
+	for ; start < end; start++ {
+		slots = append(slots, start)
+	}
+	return slots
+}
+
+func TestCleanupMissingBlockIndices(t *testing.T) {
+	for _, tt := range blockTests {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx := context.Background()
+			db := setupDB(t)
+			chain := testBlockChain(t, tt.newBlock, testSlotSlice(1, 10), nil)
+			require.NoError(t, db.SaveBlocks(ctx, chain))
+			corrupt, err := blocks.NewROBlock(chain[5])
+			require.NoError(t, err)
+			cr := corrupt.Root()
+			require.NoError(t, db.db.Update(func(tx *bolt.Tx) error {
+				return tx.Bucket(blocksBucket).Delete(cr[:])
+			}))
+			// Need to also delete it from the cache!!
+			db.blockCache.Del(string(cr[:]))
+			res, roots, err := db.Blocks(ctx, filters.NewFilter().SetEndSlot(10).SetStartSlot(1))
+			require.NoError(t, err)
+			require.Equal(t, 9, len(roots))
+			require.Equal(t, len(res), len(roots))
+			require.NoError(t, db.db.View(func(tx *bolt.Tx) error {
+				encSlot := bytesutil.SlotToBytesBigEndian(corrupt.Block().Slot())
+				// make sure slot->root index is cleaned up
+				require.Equal(t, 0, len(tx.Bucket(blockSlotIndicesBucket).Get(encSlot)))
+				require.Equal(t, 0, len(tx.Bucket(blockParentRootIndicesBucket).Get(cr[:])))
+				return nil
+			}))
+		})
+	}
+}
+
+func TestCleanupMissingForkedBlockIndices(t *testing.T) {
+	for _, tt := range blockTests[0:1] {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx := context.Background()
+			db := setupDB(t)
+
+			chain := testBlockChain(t, tt.newBlock, testSlotSlice(1, 10), nil)
+			require.NoError(t, db.SaveBlocks(ctx, chain))
+
+			// forkChain should skip the slot at skipBlock, and have the same parent
+			skipBlockParent := chain[4].Block().ParentRoot()
+			// It should start at the same slot as missingBlock, which comes one slot after the skip slot,
+			// so there are 2 blocks in that slot
+			missingBlock, err := blocks.NewROBlock(chain[5])
+			require.NoError(t, err)
+			// missingBlock will be deleted in the main chain, but there will be a block at that slot in the fork chain
+			forkChain := testBlockChain(t, tt.newBlock, testSlotSlice(missingBlock.Block().Slot(), 10), skipBlockParent[:])
+			require.NoError(t, db.SaveBlocks(ctx, forkChain))
+			forkChainStart, err := blocks.NewROBlock(forkChain[0])
+			require.NoError(t, err)
+
+			encMissingSlot := bytesutil.SlotToBytesBigEndian(missingBlock.Block().Slot())
+			require.NoError(t, db.db.View(func(tx *bolt.Tx) error {
+				require.Equal(t, 32, len(tx.Bucket(blockParentRootIndicesBucket).Get(missingBlock.RootSlice())))
+				// There are 2 block roots packed in this slot, so it is 64 bytes long
+				require.Equal(t, 64, len(tx.Bucket(blockSlotIndicesBucket).Get(encMissingSlot)))
+				// skipBlockParent should also have 2 entries and be 64 bytes, since the forkChain is based on the same parent as the skip block
+				childRoots := tx.Bucket(blockParentRootIndicesBucket).Get(skipBlockParent[:])
+				require.Equal(t, 64, len(childRoots))
+				return nil
+			}))
+
+			require.NoError(t, db.db.Update(func(tx *bolt.Tx) error {
+				return tx.Bucket(blocksBucket).Delete(missingBlock.RootSlice())
+			}))
+			// Need to also delete it from the cache!!
+			db.blockCache.Del(string(missingBlock.RootSlice()))
+
+			// Blocks should give us blocks from all chains.
+			res, roots, err := db.Blocks(ctx, filters.NewFilter().SetEndSlot(10).SetStartSlot(1))
+			require.NoError(t, err)
+			require.Equal(t, (len(chain)-1)+len(forkChain), len(roots))
+			require.Equal(t, len(res), len(roots))
+			require.NoError(t, db.db.View(func(tx *bolt.Tx) error {
+				// There should now be 32 bytes in this index - one root from the forked chain
+				slotIdxVal := tx.Bucket(blockSlotIndicesBucket).Get(encMissingSlot)
+				require.Equal(t, forkChainStart.Root(), [32]byte(slotIdxVal))
+				require.Equal(t, 0, len(tx.Bucket(blockParentRootIndicesBucket).Get(missingBlock.RootSlice())))
+				forkChildRoot := tx.Bucket(blockParentRootIndicesBucket).Get(skipBlockParent[:])
+				require.Equal(t, 64, len(forkChildRoot))
+				return nil
+			}))
+		})
+	}
+}
+
 func TestStore_Blocks_VerifyBlockRoots(t *testing.T) {
 	for _, tt := range blockTests {
 		t.Run(tt.name, func(t *testing.T) {
--- a/beacon-chain/db/kv/deposit_contract.go
+++ b/beacon-chain/db/kv/deposit_contract.go
@@ -20,7 +20,7 @@ func (s *Store) DepositContractAddress(ctx context.Context) ([]byte, error) {
 		addr = chainInfo.Get(depositContractAddressKey)
 		return nil
 	}); err != nil { // This view never returns an error, but we'll handle anyway for sanity.
-		panic(err)
+		panic(err) // lint:nopanic -- View never returns an error.
 	}
 	return addr, nil
 }
--- a/beacon-chain/db/kv/state.go
+++ b/beacon-chain/db/kv/state.go
@@ -407,7 +407,7 @@ func (s *Store) HasState(ctx context.Context, blockRoot [32]byte) bool {
 		return nil
 	})
 	if err != nil {
-		panic(err)
+		panic(err) // lint:nopanic -- View never returns an error.
 	}
 	return hasState
 }
@@ -820,30 +820,25 @@ func (s *Store) slotByBlockRoot(ctx context.Context, tx *bolt.Tx, blockRoot []by
 			// no need to construct the validator entries as it is not used here.
 			s, err := s.unmarshalState(ctx, enc, nil)
 			if err != nil {
-				return 0, err
+				return 0, errors.Wrap(err, "could not unmarshal state")
 			}
 			if s == nil || s.IsNil() {
 				return 0, errors.New("state can't be nil")
 			}
 			return s.Slot(), nil
 		}
-		b := &ethpb.SignedBeaconBlock{}
-		err := decode(ctx, enc, b)
+		b, err := unmarshalBlock(ctx, enc)
 		if err != nil {
+			return 0, errors.Wrap(err, "could not unmarshal block")
+		}
+		if err := blocks.BeaconBlockIsNil(b); err != nil {
 			return 0, err
 		}
-		wsb, err := blocks.NewSignedBeaconBlock(b)
-		if err != nil {
-			return 0, err
-		}
-		if err := blocks.BeaconBlockIsNil(wsb); err != nil {
-			return 0, err
-		}
-		return b.Block.Slot, nil
+		return b.Block().Slot(), nil
 	}
 	stateSummary := &ethpb.StateSummary{}
 	if err := decode(ctx, enc, stateSummary); err != nil {
-		return 0, err
+		return 0, errors.Wrap(err, "could not unmarshal state summary")
 	}
 	return stateSummary.Slot, nil
 }
--- a/beacon-chain/db/kv/state_test.go
+++ b/beacon-chain/db/kv/state_test.go
@@ -5,7 +5,6 @@ import (
 	"crypto/rand"
 	"encoding/binary"
 	mathRand "math/rand"
-
 	"strconv"
 	"testing"
 	"time"
@@ -1070,6 +1069,31 @@ func TestBellatrixState_CanDelete(t *testing.T) {
 	require.Equal(t, state.ReadOnlyBeaconState(nil), savedS, "Unsaved state should've been nil")
 }

+func TestBellatrixState_CanDeleteWithBlock(t *testing.T) {
+	db := setupDB(t)
+
+	b := util.NewBeaconBlockBellatrix()
+	b.Block.Slot = 100
+	r, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	wsb, err := blocks.NewSignedBeaconBlock(b)
+	require.NoError(t, err)
+	require.NoError(t, db.SaveBlock(context.Background(), wsb))
+
+	require.Equal(t, false, db.HasState(context.Background(), r))
+
+	st, _ := util.DeterministicGenesisStateBellatrix(t, 1)
+	require.NoError(t, st.SetSlot(100))
+
+	require.NoError(t, db.SaveState(context.Background(), st, r))
+	require.Equal(t, true, db.HasState(context.Background(), r))
+
+	require.NoError(t, db.DeleteState(context.Background(), r))
+	savedS, err := db.State(context.Background(), r)
+	require.NoError(t, err)
+	require.Equal(t, state.ReadOnlyBeaconState(nil), savedS, "Unsaved state should've been nil")
+}
+
 func TestDenebState_CanSaveRetrieve(t *testing.T) {
 	db := setupDB(t)

--- a/beacon-chain/db/kv/utils.go
+++ b/beacon-chain/db/kv/utils.go
@@ -114,3 +114,27 @@ func splitRoots(b []byte) ([][32]byte, error) {
 	}
 	return rl, nil
 }
+
+func removeRoot(roots []byte, root [32]byte) ([]byte, error) {
+	if len(roots) == 0 {
+		return []byte{}, nil
+	}
+	if len(roots) == 32 && bytes.Equal(roots, root[:]) {
+		return []byte{}, nil
+	}
+	if len(roots)%32 != 0 {
+		return nil, errors.Wrapf(errMisalignedRootList, "root list len=%d", len(roots))
+	}
+
+	search := root[:]
+	for i := 0; i <= len(roots)-32; i += 32 {
+		if bytes.Equal(roots[i:i+32], search) {
+			result := make([]byte, len(roots)-32)
+			copy(result, roots[:i])
+			copy(result[i:], roots[i+32:])
+			return result, nil
+		}
+	}
+
+	return roots, nil
+}
--- a/beacon-chain/db/kv/utils_test.go
+++ b/beacon-chain/db/kv/utils_test.go
@@ -1,6 +1,7 @@
 package kv

 import (
+	"bytes"
 	"context"
 	"crypto/rand"
 	"testing"
@@ -195,3 +196,85 @@ func TestSplitRoots(t *testing.T) {
 		})
 	}
 }
+
+func tPad(p ...[]byte) []byte {
+	r := make([]byte, 32*len(p))
+	for i, b := range p {
+		copy(r[i*32:], b)
+	}
+	return r
+}
+
+func TestRemoveRoot(t *testing.T) {
+	cases := []struct {
+		name   string
+		roots  []byte
+		root   [32]byte
+		expect []byte
+		err    error
+	}{
+		{
+			name:   "empty",
+			roots:  []byte{},
+			root:   [32]byte{0xde, 0xad, 0xbe, 0xef},
+			expect: []byte{},
+		},
+		{
+			name:   "single",
+			roots:  tPad([]byte{0xde, 0xad, 0xbe, 0xef}),
+			root:   [32]byte{0xde, 0xad, 0xbe, 0xef},
+			expect: []byte{},
+		},
+		{
+			name:   "single, different",
+			roots:  tPad([]byte{0xde, 0xad, 0xbe, 0xef}),
+			root:   [32]byte{0xde, 0xad, 0xbe, 0xee},
+			expect: tPad([]byte{0xde, 0xad, 0xbe, 0xef}),
+		},
+		{
+			name:   "multi",
+			roots:  tPad([]byte{0xde, 0xad, 0xbe, 0xef}, []byte{0xac, 0x1d, 0xfa, 0xce}),
+			root:   [32]byte{0xac, 0x1d, 0xfa, 0xce},
+			expect: tPad([]byte{0xde, 0xad, 0xbe, 0xef}),
+		},
+		{
+			name:   "multi, reordered",
+			roots:  tPad([]byte{0xac, 0x1d, 0xfa, 0xce}, []byte{0xde, 0xad, 0xbe, 0xef}),
+			root:   [32]byte{0xac, 0x1d, 0xfa, 0xce},
+			expect: tPad([]byte{0xde, 0xad, 0xbe, 0xef}),
+		},
+		{
+			name:   "multi, 3",
+			roots:  tPad([]byte{0xac, 0x1d, 0xfa, 0xce}, []byte{0xbe, 0xef, 0xca, 0xb5}, []byte{0xde, 0xad, 0xbe, 0xef}),
+			root:   [32]byte{0xac, 0x1d, 0xfa, 0xce},
+			expect: tPad([]byte{0xbe, 0xef, 0xca, 0xb5}, []byte{0xde, 0xad, 0xbe, 0xef}),
+		},
+		{
+			name:   "multi, different",
+			roots:  tPad([]byte{0xde, 0xad, 0xbe, 0xef}, []byte{0xac, 0x1d, 0xfa, 0xce}),
+			root:   [32]byte{0xac, 0x1d, 0xbe, 0xa7},
+			expect: tPad([]byte{0xde, 0xad, 0xbe, 0xef}, []byte{0xac, 0x1d, 0xfa, 0xce}),
+		},
+		{
+			name:  "misaligned",
+			roots: make([]byte, 61),
+			root:  [32]byte{0xac, 0x1d, 0xbe, 0xa7},
+			err:   errMisalignedRootList,
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			before := make([]byte, len(c.roots))
+			copy(before, c.roots)
+			r, err := removeRoot(c.roots, c.root)
+			if c.err != nil {
+				require.ErrorIs(t, err, c.err)
+				return
+			}
+			require.NoError(t, err)
+			require.Equal(t, len(c.expect), len(r))
+			require.Equal(t, true, bytes.Equal(c.expect, r))
+			require.Equal(t, true, bytes.Equal(before, c.roots))
+		})
+	}
+}
--- a/beacon-chain/db/kv/validated_checkpoint.go
+++ b/beacon-chain/db/kv/validated_checkpoint.go
@@ -1,8 +1,10 @@
 package kv

 import (
+	"bytes"
 	"context"

+	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing/trace"
 	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
 	bolt "go.etcd.io/bbolt"
@@ -19,7 +21,17 @@ func (s *Store) LastValidatedCheckpoint(ctx context.Context) (*ethpb.Checkpoint,
 		if enc == nil {
 			var finErr error
 			checkpoint, finErr = s.FinalizedCheckpoint(ctx)
-			return finErr
+			if finErr != nil {
+				return finErr
+			}
+			if bytes.Equal(checkpoint.Root, params.BeaconConfig().ZeroHash[:]) {
+				bkt = tx.Bucket(blocksBucket)
+				r := bkt.Get(genesisBlockRootKey)
+				if r != nil {
+					checkpoint.Root = r
+				}
+			}
+			return nil
 		}
 		checkpoint = &ethpb.Checkpoint{}
 		return decode(ctx, enc, checkpoint)
--- a/beacon-chain/db/pruner/pruner.go
+++ b/beacon-chain/db/pruner/pruner.go
@@ -16,6 +16,15 @@ import (

 var log = logrus.WithField("prefix", "db-pruner")

+const (
+	// defaultPrunableBatchSize is the number of slots that can be pruned at once.
+	defaultPrunableBatchSize = 32
+	// defaultPruningWindow is the duration of one pruning window.
+	defaultPruningWindow = time.Second * 3
+	// defaultNumBatchesToPrune is the number of batches to prune in one pruning window.
+	defaultNumBatchesToPrune = 15
+)
+
 type ServiceOption func(*Service)

 // WithRetentionPeriod allows the user to specify a different data retention period than the spec default.
@@ -143,14 +152,17 @@ func (p *Service) prune(slot primitives.Slot) error {
 	}).Debug("Pruning chain data")

 	tt := time.Now()
-	if err := p.db.DeleteHistoricalDataBeforeSlot(p.ctx, pruneUpto); err != nil {
-		return errors.Wrapf(err, "could not delete upto slot %d", pruneUpto)
+	numBatches, err := p.pruneBatches(pruneUpto)
+	if err != nil {
+		return errors.Wrap(err, "failed to prune batches")
 	}

 	log.WithFields(logrus.Fields{
 		"prunedUpto":  pruneUpto,
 		"duration":    time.Since(tt),
 		"currentSlot": slot,
+		"batchSize":   defaultPrunableBatchSize,
+		"numBatches":  numBatches,
 	}).Debug("Successfully pruned chain data")

 	// Update pruning checkpoint.
@@ -159,6 +171,33 @@ func (p *Service) prune(slot primitives.Slot) error {
 	return nil
 }

+func (p *Service) pruneBatches(pruneUpto primitives.Slot) (int, error) {
+	ctx, cancel := context.WithTimeout(p.ctx, defaultPruningWindow)
+	defer cancel()
+
+	numBatches := 0
+	for {
+		select {
+		case <-ctx.Done():
+			return numBatches, nil
+		default:
+			for i := 0; i < defaultNumBatchesToPrune; i++ {
+				slotsDeleted, err := p.db.DeleteHistoricalDataBeforeSlot(ctx, pruneUpto, defaultPrunableBatchSize)
+				if err != nil {
+					return 0, errors.Wrapf(err, "could not delete upto slot %d", pruneUpto)
+				}
+
+				// Return if there's nothing to delete.
+				if slotsDeleted == 0 {
+					return numBatches, nil
+				}
+
+				numBatches++
+			}
+		}
+	}
+}
+
 // pruneStartSlotFunc returns the function to determine the start slot to start pruning.
 func pruneStartSlotFunc(retentionEpochs primitives.Epoch) func(primitives.Slot) primitives.Slot {
 	return func(current primitives.Slot) primitives.Slot {
--- a/beacon-chain/db/slasherkv/slasher_test.go
+++ b/beacon-chain/db/slasherkv/slasher_test.go
@@ -587,7 +587,7 @@ func BenchmarkHighestAttestations(b *testing.B) {
 	beaconDB := setupDB(b)
 	require.NoError(b, beaconDB.SaveAttestationRecordsForValidators(ctx, atts))

-	allIndices := make([]primitives.ValidatorIndex, valsPerAtt*count)
+	allIndices := make([]primitives.ValidatorIndex, 0, valsPerAtt*count)
 	for i := 0; i < count; i++ {
 		indicesForAtt := make([]primitives.ValidatorIndex, valsPerAtt)
 		for r := 0; r < valsPerAtt; r++ {
--- a/Show More
+++ b/Show More