removing error package alias

**What type of PR is this?**
Other

**What does this PR do? Why is it needed?**

**Which issues(s) does this PR fix?**

Fixes #

**Other notes for review**

a node that is in syncing or optimistic status isn't fully ready yet. we
don't have a is ready endpoint, but I think having the gRPC match more
closely to
[/eth/v1/node/health](https://ethereum.github.io/beacon-APIs/?urls.primaryName=dev#/Node/getHealth)
would be good. This endpoint is only used internally as far as I can
tell.

this is prerequisite to https://github.com/OffchainLabs/prysm/pull/16215

tested via grpcurl against a syncing hoodi node

**Acknowledgements**

- [x] I have read
[CONTRIBUTING.md](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md).
- [x] I have included a uniquely named [changelog fragment
file](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md#maintaining-changelogmd).
- [x] I have added a description with sufficient context for reviewers
to understand this PR.
- [x] I have tested that my changes work as expected and I added a
testing plan to the PR description (if applicable).

api/grpc/BUILD.bazel

@@ -3,13 +3,16 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = [
+        "grpc_connection_provider.go",
         "grpcutils.go",
         "log.go",
+        "mock_grpc_provider.go",
         "parameters.go",
     ],
     importpath = "github.com/OffchainLabs/prysm/v7/api/grpc",
     visibility = ["//visibility:public"],
     deps = [
+        "@com_github_pkg_errors//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
         "@org_golang_google_grpc//:go_default_library",
         "@org_golang_google_grpc//metadata:go_default_library",
@@ -18,12 +21,17 @@ go_library(
 
 go_test(
     name = "go_default_test",
-    srcs = ["grpcutils_test.go"],
+    srcs = [
+        "grpc_connection_provider_test.go",
+        "grpcutils_test.go",
+    ],
     embed = [":go_default_library"],
     deps = [
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
         "@com_github_sirupsen_logrus//hooks/test:go_default_library",
+        "@org_golang_google_grpc//:go_default_library",
+        "@org_golang_google_grpc//credentials/insecure:go_default_library",
         "@org_golang_google_grpc//metadata:go_default_library",
     ],
 )

api/grpc/grpc_connection_provider.go

@@ -0,0 +1,173 @@
+package grpc
+
+import (
+	"context"
+	"strings"
+	"sync"
+
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"google.golang.org/grpc"
+)
+
+// GrpcConnectionProvider manages gRPC connections for failover support.
+// It allows switching between different beacon node endpoints when the current one becomes unavailable.
+// Only one connection is maintained at a time - when switching hosts, the old connection is closed.
+type GrpcConnectionProvider interface {
+	// CurrentConn returns the currently active gRPC connection.
+	// The connection is created lazily on first call.
+	// Returns nil if the provider has been closed.
+	CurrentConn() *grpc.ClientConn
+	// CurrentHost returns the address of the currently active endpoint.
+	CurrentHost() string
+	// Hosts returns all configured endpoint addresses.
+	Hosts() []string
+	// SwitchHost switches to the endpoint at the given index.
+	// The new connection is created lazily on next CurrentConn() call.
+	SwitchHost(index int) error
+	// Close closes the current connection.
+	Close()
+}
+
+type grpcConnectionProvider struct {
+	// Immutable after construction - no lock needed for reads
+	endpoints []string
+	ctx       context.Context
+	dialOpts  []grpc.DialOption
+
+	// Current connection state (protected by mutex)
+	currentIndex uint64
+	conn         *grpc.ClientConn
+
+	mu     sync.Mutex
+	closed bool
+}
+
+// NewGrpcConnectionProvider creates a new connection provider that manages gRPC connections.
+// The endpoint parameter can be a comma-separated list of addresses (e.g., "host1:4000,host2:4000").
+// Only one connection is maintained at a time, created lazily on first use.
+func NewGrpcConnectionProvider(
+	ctx context.Context,
+	endpoint string,
+	dialOpts []grpc.DialOption,
+) (GrpcConnectionProvider, error) {
+	endpoints := parseEndpoints(endpoint)
+	if len(endpoints) == 0 {
+		return nil, errors.New("no gRPC endpoints provided")
+	}
+
+	log.WithFields(logrus.Fields{
+		"endpoints": endpoints,
+		"count":     len(endpoints),
+	}).Info("Initialized gRPC connection provider")
+
+	return &grpcConnectionProvider{
+		endpoints: endpoints,
+		ctx:       ctx,
+		dialOpts:  dialOpts,
+	}, nil
+}
+
+// parseEndpoints splits a comma-separated endpoint string into individual endpoints.
+func parseEndpoints(endpoint string) []string {
+	if endpoint == "" {
+		return nil
+	}
+	endpoints := make([]string, 0, 1)
+	for p := range strings.SplitSeq(endpoint, ",") {
+		if p = strings.TrimSpace(p); p != "" {
+			endpoints = append(endpoints, p)
+		}
+	}
+	return endpoints
+}
+
+func (p *grpcConnectionProvider) CurrentConn() *grpc.ClientConn {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if p.closed {
+		return nil
+	}
+
+	// Return existing connection if available
+	if p.conn != nil {
+		return p.conn
+	}
+
+	// Create connection lazily
+	ep := p.endpoints[p.currentIndex]
+	conn, err := grpc.DialContext(p.ctx, ep, p.dialOpts...)
+	if err != nil {
+		log.WithError(err).WithField("endpoint", ep).Error("Failed to create gRPC connection")
+		return nil
+	}
+
+	p.conn = conn
+	log.WithField("endpoint", ep).Debug("Created gRPC connection")
+	return conn
+}
+
+func (p *grpcConnectionProvider) CurrentHost() string {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	return p.endpoints[p.currentIndex]
+}
+
+func (p *grpcConnectionProvider) Hosts() []string {
+	// Return a copy to maintain immutability
+	hosts := make([]string, len(p.endpoints))
+	copy(hosts, p.endpoints)
+	return hosts
+}
+
+func (p *grpcConnectionProvider) SwitchHost(index int) error {
+	if index < 0 || index >= len(p.endpoints) {
+		return errors.Errorf("invalid host index %d, must be between 0 and %d", index, len(p.endpoints)-1)
+	}
+
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if uint64(index) == p.currentIndex {
+		return nil // Already on this host
+	}
+
+	oldHost := p.endpoints[p.currentIndex]
+	oldConn := p.conn
+
+	p.conn = nil // Clear immediately - new connection created lazily
+	p.currentIndex = uint64(index)
+
+	// Close old connection asynchronously to avoid blocking the caller
+	if oldConn != nil {
+		go func() {
+			if err := oldConn.Close(); err != nil {
+				log.WithError(err).WithField("endpoint", oldHost).Debug("Failed to close previous connection")
+			}
+		}()
+	}
+
+	log.WithFields(logrus.Fields{
+		"previousHost": oldHost,
+		"newHost":      p.endpoints[index],
+	}).Debug("Switched gRPC endpoint")
+	return nil
+}
+
+func (p *grpcConnectionProvider) Close() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if p.closed {
+		return
+	}
+	p.closed = true
+
+	if p.conn != nil {
+		if err := p.conn.Close(); err != nil {
+			log.WithError(err).WithField("endpoint", p.endpoints[p.currentIndex]).Debug("Failed to close gRPC connection")
+		}
+		p.conn = nil
+	}
+}

api/grpc/grpc_connection_provider_test.go

@@ -0,0 +1,207 @@
+package grpc
+
+import (
+	"context"
+	"net"
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v7/testing/assert"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+)
+
+func TestParseEndpoints(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected []string
+	}{
+		{"single endpoint", "localhost:4000", []string{"localhost:4000"}},
+		{"multiple endpoints", "host1:4000,host2:4000,host3:4000", []string{"host1:4000", "host2:4000", "host3:4000"}},
+		{"endpoints with spaces", "host1:4000, host2:4000 , host3:4000", []string{"host1:4000", "host2:4000", "host3:4000"}},
+		{"empty string", "", nil},
+		{"only commas", ",,,", []string{}},
+		{"trailing comma", "host1:4000,host2:4000,", []string{"host1:4000", "host2:4000"}},
+		{"leading comma", ",host1:4000,host2:4000", []string{"host1:4000", "host2:4000"}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parseEndpoints(tt.input)
+			if !reflect.DeepEqual(tt.expected, got) {
+				t.Errorf("parseEndpoints(%q) = %v, want %v", tt.input, got, tt.expected)
+			}
+		})
+	}
+}
+
+func TestNewGrpcConnectionProvider_Errors(t *testing.T) {
+	t.Run("no endpoints", func(t *testing.T) {
+		dialOpts := []grpc.DialOption{grpc.WithTransportCredentials(insecure.NewCredentials())}
+		_, err := NewGrpcConnectionProvider(context.Background(), "", dialOpts)
+		require.ErrorContains(t, "no gRPC endpoints provided", err)
+	})
+}
+
+func TestGrpcConnectionProvider_LazyConnection(t *testing.T) {
+	// Start only one server but configure provider with two endpoints
+	lis, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+	server := grpc.NewServer()
+	go func() { _ = server.Serve(lis) }()
+	defer server.Stop()
+
+	validAddr := lis.Addr().String()
+	invalidAddr := "127.0.0.1:1" // Port 1 is unlikely to be listening
+
+	// Provider should succeed even though second endpoint is invalid (lazy connections)
+	endpoint := validAddr + "," + invalidAddr
+	ctx := context.Background()
+	dialOpts := []grpc.DialOption{grpc.WithTransportCredentials(insecure.NewCredentials())}
+	provider, err := NewGrpcConnectionProvider(ctx, endpoint, dialOpts)
+	require.NoError(t, err, "Provider creation should succeed with lazy connections")
+	defer func() { provider.Close() }()
+
+	// First endpoint should work
+	conn := provider.CurrentConn()
+	assert.NotNil(t, conn, "First connection should be created lazily")
+}
+
+func TestGrpcConnectionProvider_SingleConnectionModel(t *testing.T) {
+	// Create provider with 3 endpoints
+	var addrs []string
+	var servers []*grpc.Server
+
+	for range 3 {
+		lis, err := net.Listen("tcp", "127.0.0.1:0")
+		require.NoError(t, err)
+		server := grpc.NewServer()
+		go func() { _ = server.Serve(lis) }()
+		addrs = append(addrs, lis.Addr().String())
+		servers = append(servers, server)
+	}
+	defer func() {
+		for _, s := range servers {
+			s.Stop()
+		}
+	}()
+
+	endpoint := strings.Join(addrs, ",")
+	ctx := context.Background()
+	dialOpts := []grpc.DialOption{grpc.WithTransportCredentials(insecure.NewCredentials())}
+	provider, err := NewGrpcConnectionProvider(ctx, endpoint, dialOpts)
+	require.NoError(t, err)
+	defer func() { provider.Close() }()
+
+	// Access the internal state to verify single connection behavior
+	p := provider.(*grpcConnectionProvider)
+
+	// Initially no connection
+	p.mu.Lock()
+	assert.Equal(t, (*grpc.ClientConn)(nil), p.conn, "Connection should be nil before access")
+	p.mu.Unlock()
+
+	// Access connection - should create one
+	conn0 := provider.CurrentConn()
+	assert.NotNil(t, conn0)
+
+	p.mu.Lock()
+	assert.NotNil(t, p.conn, "Connection should be created after CurrentConn()")
+	firstConn := p.conn
+	p.mu.Unlock()
+
+	// Call CurrentConn again - should return same connection
+	conn0Again := provider.CurrentConn()
+	assert.Equal(t, conn0, conn0Again, "Should return same connection")
+
+	// Switch to different host - old connection should be closed, new one created lazily
+	require.NoError(t, provider.SwitchHost(1))
+
+	p.mu.Lock()
+	assert.Equal(t, (*grpc.ClientConn)(nil), p.conn, "Connection should be nil after SwitchHost (lazy)")
+	p.mu.Unlock()
+
+	// Get new connection
+	conn1 := provider.CurrentConn()
+	assert.NotNil(t, conn1)
+	assert.NotEqual(t, firstConn, conn1, "Should be a different connection after switching hosts")
+}
+
+// testProvider creates a provider with n test servers and returns cleanup function.
+func testProvider(t *testing.T, n int) (GrpcConnectionProvider, []string, func()) {
+	var addrs []string
+	var cleanups []func()
+
+	for range n {
+		lis, err := net.Listen("tcp", "127.0.0.1:0")
+		require.NoError(t, err)
+		server := grpc.NewServer()
+		go func() { _ = server.Serve(lis) }()
+		addrs = append(addrs, lis.Addr().String())
+		cleanups = append(cleanups, server.Stop)
+	}
+
+	endpoint := strings.Join(addrs, ",")
+
+	ctx := context.Background()
+	dialOpts := []grpc.DialOption{grpc.WithTransportCredentials(insecure.NewCredentials())}
+	provider, err := NewGrpcConnectionProvider(ctx, endpoint, dialOpts)
+	require.NoError(t, err)
+
+	cleanup := func() {
+		provider.Close()
+		for _, c := range cleanups {
+			c()
+		}
+	}
+	return provider, addrs, cleanup
+}
+
+func TestGrpcConnectionProvider(t *testing.T) {
+	provider, addrs, cleanup := testProvider(t, 3)
+	defer cleanup()
+
+	t.Run("initial state", func(t *testing.T) {
+		assert.Equal(t, 3, len(provider.Hosts()))
+		assert.Equal(t, addrs[0], provider.CurrentHost())
+		assert.NotNil(t, provider.CurrentConn())
+	})
+
+	t.Run("SwitchHost", func(t *testing.T) {
+		require.NoError(t, provider.SwitchHost(1))
+		assert.Equal(t, addrs[1], provider.CurrentHost())
+		assert.NotNil(t, provider.CurrentConn()) // New connection created lazily
+		require.NoError(t, provider.SwitchHost(0))
+		assert.Equal(t, addrs[0], provider.CurrentHost())
+		require.ErrorContains(t, "invalid host index", provider.SwitchHost(-1))
+		require.ErrorContains(t, "invalid host index", provider.SwitchHost(3))
+	})
+
+	t.Run("SwitchHost circular", func(t *testing.T) {
+		// Test round-robin style switching using SwitchHost with manual index
+		indices := []int{1, 2, 0, 1} // Simulate circular switching
+		for i, idx := range indices {
+			require.NoError(t, provider.SwitchHost(idx))
+			assert.Equal(t, addrs[idx], provider.CurrentHost(), "iteration %d", i)
+		}
+	})
+
+	t.Run("Hosts returns copy", func(t *testing.T) {
+		hosts := provider.Hosts()
+		original := hosts[0]
+		hosts[0] = "modified"
+		assert.Equal(t, original, provider.Hosts()[0])
+	})
+}
+
+func TestGrpcConnectionProvider_Close(t *testing.T) {
+	provider, _, cleanup := testProvider(t, 1)
+	defer cleanup()
+
+	assert.NotNil(t, provider.CurrentConn())
+	provider.Close()
+	assert.Equal(t, (*grpc.ClientConn)(nil), provider.CurrentConn())
+	provider.Close() // Double close is safe
+}

api/grpc/mock_grpc_provider.go

@@ -0,0 +1,20 @@
+package grpc
+
+import "google.golang.org/grpc"
+
+// MockGrpcProvider implements GrpcConnectionProvider for testing.
+type MockGrpcProvider struct {
+	MockConn  *grpc.ClientConn
+	MockHosts []string
+}
+
+func (m *MockGrpcProvider) CurrentConn() *grpc.ClientConn { return m.MockConn }
+func (m *MockGrpcProvider) CurrentHost() string {
+	if len(m.MockHosts) > 0 {
+		return m.MockHosts[0]
+	}
+	return ""
+}
+func (m *MockGrpcProvider) Hosts() []string      { return m.MockHosts }
+func (m *MockGrpcProvider) SwitchHost(int) error { return nil }
+func (m *MockGrpcProvider) Close()               {}

api/rest/BUILD.bazel

@@ -0,0 +1,34 @@
+load("@prysm//tools/go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "log.go",
+        "mock_rest_provider.go",
+        "rest_connection_provider.go",
+        "rest_handler.go",
+    ],
+    importpath = "github.com/OffchainLabs/prysm/v7/api/rest",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//api:go_default_library",
+        "//api/apiutil:go_default_library",
+        "//api/client:go_default_library",
+        "//config/params:go_default_library",
+        "//network/httputil:go_default_library",
+        "//runtime/version:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
+        "@com_github_sirupsen_logrus//:go_default_library",
+        "@io_opentelemetry_go_contrib_instrumentation_net_http_otelhttp//:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["rest_connection_provider_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "//testing/assert:go_default_library",
+        "//testing/require:go_default_library",
+    ],
+)

api/rest/log.go

@@ -0,0 +1,9 @@
+// Code generated by hack/gen-logs.sh; DO NOT EDIT.
+// This file is created and regenerated automatically. Anything added here might get removed.
+package rest
+
+import "github.com/sirupsen/logrus"
+
+// The prefix for logs from this package will be the text after the last slash in the package path.
+// If you wish to change this, you should add your desired name in the runtime/logging/logrus-prefixed-formatter/prefix-replacement.go file.
+var log = logrus.WithField("package", "api/rest")

api/rest/mock_rest_provider.go

@@ -0,0 +1,49 @@
+package rest
+
+import (
+	"bytes"
+	"context"
+	"net/http"
+)
+
+// MockRestProvider implements RestConnectionProvider for testing.
+type MockRestProvider struct {
+	MockClient  *http.Client
+	MockHandler RestHandler
+	MockHosts   []string
+	HostIndex   int
+}
+
+func (m *MockRestProvider) HttpClient() *http.Client { return m.MockClient }
+func (m *MockRestProvider) RestHandler() RestHandler { return m.MockHandler }
+func (m *MockRestProvider) CurrentHost() string {
+	if len(m.MockHosts) > 0 {
+		return m.MockHosts[m.HostIndex%len(m.MockHosts)]
+	}
+	return ""
+}
+func (m *MockRestProvider) Hosts() []string            { return m.MockHosts }
+func (m *MockRestProvider) SwitchHost(index int) error { m.HostIndex = index; return nil }
+
+// MockRestHandler implements RestHandler for testing.
+type MockRestHandler struct {
+	MockHost   string
+	MockClient *http.Client
+}
+
+func (m *MockRestHandler) Get(_ context.Context, _ string, _ any) error { return nil }
+func (m *MockRestHandler) GetStatusCode(_ context.Context, _ string) (int, error) {
+	return http.StatusOK, nil
+}
+func (m *MockRestHandler) GetSSZ(_ context.Context, _ string) ([]byte, http.Header, error) {
+	return nil, nil, nil
+}
+func (m *MockRestHandler) Post(_ context.Context, _ string, _ map[string]string, _ *bytes.Buffer, _ any) error {
+	return nil
+}
+func (m *MockRestHandler) PostSSZ(_ context.Context, _ string, _ map[string]string, _ *bytes.Buffer) ([]byte, http.Header, error) {
+	return nil, nil, nil
+}
+func (m *MockRestHandler) HttpClient() *http.Client { return m.MockClient }
+func (m *MockRestHandler) Host() string             { return m.MockHost }
+func (m *MockRestHandler) SwitchHost(host string)   { m.MockHost = host }

api/rest/rest_connection_provider.go

@@ -0,0 +1,158 @@
+package rest
+
+import (
+	"net/http"
+	"strings"
+	"sync/atomic"
+	"time"
+
+	"github.com/OffchainLabs/prysm/v7/api/client"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
+)
+
+// RestConnectionProvider manages HTTP client configuration for REST API with failover support.
+// It allows switching between different beacon node REST endpoints when the current one becomes unavailable.
+type RestConnectionProvider interface {
+	// HttpClient returns the configured HTTP client with headers, timeout, and optional tracing.
+	HttpClient() *http.Client
+	// RestHandler returns the REST handler for making API requests.
+	RestHandler() RestHandler
+	// CurrentHost returns the current REST API endpoint URL.
+	CurrentHost() string
+	// Hosts returns all configured REST API endpoint URLs.
+	Hosts() []string
+	// SwitchHost switches to the endpoint at the given index.
+	SwitchHost(index int) error
+}
+
+// RestConnectionProviderOption is a functional option for configuring the REST connection provider.
+type RestConnectionProviderOption func(*restConnectionProvider)
+
+// WithHttpTimeout sets the HTTP client timeout.
+func WithHttpTimeout(timeout time.Duration) RestConnectionProviderOption {
+	return func(p *restConnectionProvider) {
+		p.timeout = timeout
+	}
+}
+
+// WithHttpHeaders sets custom HTTP headers to include in all requests.
+func WithHttpHeaders(headers map[string][]string) RestConnectionProviderOption {
+	return func(p *restConnectionProvider) {
+		p.headers = headers
+	}
+}
+
+// WithTracing enables OpenTelemetry tracing for HTTP requests.
+func WithTracing() RestConnectionProviderOption {
+	return func(p *restConnectionProvider) {
+		p.enableTracing = true
+	}
+}
+
+type restConnectionProvider struct {
+	endpoints     []string
+	httpClient    *http.Client
+	restHandler   RestHandler
+	currentIndex  atomic.Uint64
+	timeout       time.Duration
+	headers       map[string][]string
+	enableTracing bool
+}
+
+// NewRestConnectionProvider creates a new REST connection provider that manages HTTP client configuration.
+// The endpoint parameter can be a comma-separated list of URLs (e.g., "http://host1:3500,http://host2:3500").
+func NewRestConnectionProvider(endpoint string, opts ...RestConnectionProviderOption) (RestConnectionProvider, error) {
+	endpoints := parseEndpoints(endpoint)
+	if len(endpoints) == 0 {
+		return nil, errors.New("no REST API endpoints provided")
+	}
+
+	p := &restConnectionProvider{
+		endpoints: endpoints,
+	}
+
+	for _, opt := range opts {
+		opt(p)
+	}
+
+	// Build the HTTP transport chain
+	var transport http.RoundTripper = http.DefaultTransport
+
+	// Add custom headers if configured
+	if len(p.headers) > 0 {
+		transport = client.NewCustomHeadersTransport(transport, p.headers)
+	}
+
+	// Add tracing if enabled
+	if p.enableTracing {
+		transport = otelhttp.NewTransport(transport)
+	}
+
+	p.httpClient = &http.Client{
+		Timeout:   p.timeout,
+		Transport: transport,
+	}
+
+	// Create the REST handler with the HTTP client and initial host
+	p.restHandler = newRestHandler(*p.httpClient, endpoints[0])
+
+	log.WithFields(logrus.Fields{
+		"endpoints": endpoints,
+		"count":     len(endpoints),
+	}).Info("Initialized REST connection provider")
+
+	return p, nil
+}
+
+// parseEndpoints splits a comma-separated endpoint string into individual endpoints.
+func parseEndpoints(endpoint string) []string {
+	if endpoint == "" {
+		return nil
+	}
+	endpoints := make([]string, 0, 1)
+	for p := range strings.SplitSeq(endpoint, ",") {
+		if p = strings.TrimSpace(p); p != "" {
+			endpoints = append(endpoints, p)
+		}
+	}
+	return endpoints
+}
+
+func (p *restConnectionProvider) HttpClient() *http.Client {
+	return p.httpClient
+}
+
+func (p *restConnectionProvider) RestHandler() RestHandler {
+	return p.restHandler
+}
+
+func (p *restConnectionProvider) CurrentHost() string {
+	return p.endpoints[p.currentIndex.Load()]
+}
+
+func (p *restConnectionProvider) Hosts() []string {
+	// Return a copy to maintain immutability
+	hosts := make([]string, len(p.endpoints))
+	copy(hosts, p.endpoints)
+	return hosts
+}
+
+func (p *restConnectionProvider) SwitchHost(index int) error {
+	if index < 0 || index >= len(p.endpoints) {
+		return errors.Errorf("invalid host index %d, must be between 0 and %d", index, len(p.endpoints)-1)
+	}
+
+	oldIdx := p.currentIndex.Load()
+	p.currentIndex.Store(uint64(index))
+
+	// Update the rest handler's host
+	p.restHandler.SwitchHost(p.endpoints[index])
+
+	log.WithFields(logrus.Fields{
+		"previousHost": p.endpoints[oldIdx],
+		"newHost":      p.endpoints[index],
+	}).Debug("Switched REST endpoint")
+	return nil
+}

api/rest/rest_connection_provider_test.go

@@ -0,0 +1,80 @@
+package rest
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v7/testing/assert"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+)
+
+func TestParseEndpoints(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected []string
+	}{
+		{"single endpoint", "http://localhost:3500", []string{"http://localhost:3500"}},
+		{"multiple endpoints", "http://host1:3500,http://host2:3500,http://host3:3500", []string{"http://host1:3500", "http://host2:3500", "http://host3:3500"}},
+		{"endpoints with spaces", "http://host1:3500, http://host2:3500 , http://host3:3500", []string{"http://host1:3500", "http://host2:3500", "http://host3:3500"}},
+		{"empty string", "", nil},
+		{"only commas", ",,,", []string{}},
+		{"trailing comma", "http://host1:3500,http://host2:3500,", []string{"http://host1:3500", "http://host2:3500"}},
+		{"leading comma", ",http://host1:3500,http://host2:3500", []string{"http://host1:3500", "http://host2:3500"}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parseEndpoints(tt.input)
+			if !reflect.DeepEqual(tt.expected, got) {
+				t.Errorf("parseEndpoints(%q) = %v, want %v", tt.input, got, tt.expected)
+			}
+		})
+	}
+}
+
+func TestNewRestConnectionProvider_Errors(t *testing.T) {
+	t.Run("no endpoints", func(t *testing.T) {
+		_, err := NewRestConnectionProvider("")
+		require.ErrorContains(t, "no REST API endpoints provided", err)
+	})
+}
+
+func TestRestConnectionProvider(t *testing.T) {
+	provider, err := NewRestConnectionProvider("http://host1:3500,http://host2:3500,http://host3:3500")
+	require.NoError(t, err)
+
+	t.Run("initial state", func(t *testing.T) {
+		assert.Equal(t, 3, len(provider.Hosts()))
+		assert.Equal(t, "http://host1:3500", provider.CurrentHost())
+		assert.NotNil(t, provider.HttpClient())
+	})
+
+	t.Run("SwitchHost", func(t *testing.T) {
+		require.NoError(t, provider.SwitchHost(1))
+		assert.Equal(t, "http://host2:3500", provider.CurrentHost())
+		require.NoError(t, provider.SwitchHost(0))
+		assert.Equal(t, "http://host1:3500", provider.CurrentHost())
+		require.ErrorContains(t, "invalid host index", provider.SwitchHost(-1))
+		require.ErrorContains(t, "invalid host index", provider.SwitchHost(3))
+	})
+
+	t.Run("Hosts returns copy", func(t *testing.T) {
+		hosts := provider.Hosts()
+		original := hosts[0]
+		hosts[0] = "modified"
+		assert.Equal(t, original, provider.Hosts()[0])
+	})
+}
+
+func TestRestConnectionProvider_WithOptions(t *testing.T) {
+	headers := map[string][]string{"Authorization": {"Bearer token"}}
+	provider, err := NewRestConnectionProvider(
+		"http://localhost:3500",
+		WithHttpHeaders(headers),
+		WithHttpTimeout(30000000000), // 30 seconds in nanoseconds
+		WithTracing(),
+	)
+	require.NoError(t, err)
+	assert.NotNil(t, provider.HttpClient())
+	assert.Equal(t, "http://localhost:3500", provider.CurrentHost())
+}

api/rest/rest_handler.go

@@ -1,4 +1,4 @@
-package beacon_api
+package rest
 
 import (
 	"bytes"
@@ -21,6 +21,7 @@ import (
 
 type reqOption func(*http.Request)
 
+// RestHandler defines the interface for making REST API requests.
 type RestHandler interface {
 	Get(ctx context.Context, endpoint string, resp any) error
 	GetStatusCode(ctx context.Context, endpoint string) (int, error)
@@ -29,29 +30,34 @@ type RestHandler interface {
 	PostSSZ(ctx context.Context, endpoint string, headers map[string]string, data *bytes.Buffer) ([]byte, http.Header, error)
 	HttpClient() *http.Client
 	Host() string
-	SetHost(host string)
+	SwitchHost(host string)
 }
 
-type BeaconApiRestHandler struct {
+type restHandler struct {
 	client       http.Client
 	host         string
 	reqOverrides []reqOption
 }
 
-// NewBeaconApiRestHandler returns a RestHandler
-func NewBeaconApiRestHandler(client http.Client, host string) RestHandler {
-	brh := &BeaconApiRestHandler{
+// newRestHandler returns a RestHandler (internal use)
+func newRestHandler(client http.Client, host string) RestHandler {
+	return NewRestHandler(client, host)
+}
+
+// NewRestHandler returns a RestHandler
+func NewRestHandler(client http.Client, host string) RestHandler {
+	rh := &restHandler{
 		client: client,
 		host:   host,
 	}
-	brh.appendAcceptOverride()
-	return brh
+	rh.appendAcceptOverride()
+	return rh
 }
 
 // appendAcceptOverride enables the Accept header to be customized at runtime via an environment variable.
 // This is specified as an env var because it is a niche option that prysm may use for performance testing or debugging
 // bug which users are unlikely to need. Using an env var keeps the set of user-facing flags cleaner.
-func (c *BeaconApiRestHandler) appendAcceptOverride() {
+func (c *restHandler) appendAcceptOverride() {
 	if accept := os.Getenv(params.EnvNameOverrideAccept); accept != "" {
 		c.reqOverrides = append(c.reqOverrides, func(req *http.Request) {
 			req.Header.Set("Accept", accept)
@@ -60,18 +66,18 @@ func (c *BeaconApiRestHandler) appendAcceptOverride() {
 }
 
 // HttpClient returns the underlying HTTP client of the handler
-func (c *BeaconApiRestHandler) HttpClient() *http.Client {
+func (c *restHandler) HttpClient() *http.Client {
 	return &c.client
 }
 
 // Host returns the underlying HTTP host
-func (c *BeaconApiRestHandler) Host() string {
+func (c *restHandler) Host() string {
 	return c.host
 }
 
 // Get sends a GET request and decodes the response body as a JSON object into the passed in object.
 // If an HTTP error is returned, the body is decoded as a DefaultJsonError JSON object and returned as the first return value.
-func (c *BeaconApiRestHandler) Get(ctx context.Context, endpoint string, resp any) error {
+func (c *restHandler) Get(ctx context.Context, endpoint string, resp any) error {
 	url := c.host + endpoint
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
 	if err != nil {
@@ -94,7 +100,7 @@ func (c *BeaconApiRestHandler) Get(ctx context.Context, endpoint string, resp an
 // GetStatusCode sends a GET request and returns only the HTTP status code.
 // This is useful for endpoints like /eth/v1/node/health that communicate status via HTTP codes
 // (200 = ready, 206 = syncing, 503 = unavailable) rather than response bodies.
-func (c *BeaconApiRestHandler) GetStatusCode(ctx context.Context, endpoint string) (int, error) {
+func (c *restHandler) GetStatusCode(ctx context.Context, endpoint string) (int, error) {
 	url := c.host + endpoint
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
 	if err != nil {
@@ -113,7 +119,7 @@ func (c *BeaconApiRestHandler) GetStatusCode(ctx context.Context, endpoint strin
 	return httpResp.StatusCode, nil
 }
 
-func (c *BeaconApiRestHandler) GetSSZ(ctx context.Context, endpoint string) ([]byte, http.Header, error) {
+func (c *restHandler) GetSSZ(ctx context.Context, endpoint string) ([]byte, http.Header, error) {
 	url := c.host + endpoint
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
 	if err != nil {
@@ -168,7 +174,7 @@ func (c *BeaconApiRestHandler) GetSSZ(ctx context.Context, endpoint string) ([]b
 
 // Post sends a POST request and decodes the response body as a JSON object into the passed in object.
 // If an HTTP error is returned, the body is decoded as a DefaultJsonError JSON object and returned as the first return value.
-func (c *BeaconApiRestHandler) Post(
+func (c *restHandler) Post(
 	ctx context.Context,
 	apiEndpoint string,
 	headers map[string]string,
@@ -204,7 +210,7 @@ func (c *BeaconApiRestHandler) Post(
 }
 
 // PostSSZ sends a POST request and prefers an SSZ (application/octet-stream) response body.
-func (c *BeaconApiRestHandler) PostSSZ(
+func (c *restHandler) PostSSZ(
 	ctx context.Context,
 	apiEndpoint string,
 	headers map[string]string,
@@ -305,6 +311,6 @@ func decodeResp(httpResp *http.Response, resp any) error {
 	return nil
 }
 
-func (c *BeaconApiRestHandler) SetHost(host string) {
+func (c *restHandler) SwitchHost(host string) {
 	c.host = host
 }

beacon-chain/rpc/prysm/v1alpha1/node/BUILD.bazel

@@ -48,6 +48,7 @@ go_test(
         "@com_github_ethereum_go_ethereum//crypto:go_default_library",
         "@com_github_ethereum_go_ethereum//p2p/enode:go_default_library",
         "@org_golang_google_grpc//:go_default_library",
+        "@org_golang_google_grpc//metadata:go_default_library",
         "@org_golang_google_grpc//reflection:go_default_library",
         "@org_golang_google_protobuf//types/known/emptypb:go_default_library",
         "@org_golang_google_protobuf//types/known/timestamppb:go_default_library",

beacon-chain/rpc/prysm/v1alpha1/node/server.go

@@ -35,18 +35,19 @@ import (
 // providing RPC endpoints for verifying a beacon node's sync status, genesis and
 // version information, and services the node implements and runs.
 type Server struct {
-	LogsStreamer         logs.Streamer
-	StreamLogsBufferSize int
-	SyncChecker          sync.Checker
-	Server               *grpc.Server
-	BeaconDB             db.ReadOnlyDatabase
-	PeersFetcher         p2p.PeersProvider
-	PeerManager          p2p.PeerManager
-	GenesisTimeFetcher   blockchain.TimeFetcher
-	GenesisFetcher       blockchain.GenesisFetcher
-	POWChainInfoFetcher  execution.ChainInfoFetcher
-	BeaconMonitoringHost string
-	BeaconMonitoringPort int
+	LogsStreamer          logs.Streamer
+	StreamLogsBufferSize  int
+	SyncChecker           sync.Checker
+	Server                *grpc.Server
+	BeaconDB              db.ReadOnlyDatabase
+	PeersFetcher          p2p.PeersProvider
+	PeerManager           p2p.PeerManager
+	GenesisTimeFetcher    blockchain.TimeFetcher
+	GenesisFetcher        blockchain.GenesisFetcher
+	POWChainInfoFetcher   execution.ChainInfoFetcher
+	BeaconMonitoringHost  string
+	BeaconMonitoringPort  int
+	OptimisticModeFetcher blockchain.OptimisticModeFetcher
 }
 
 // Deprecated: The gRPC API will remain the default and fully supported through v8 (expected in 2026) but will be eventually removed in favor of REST API.
@@ -61,21 +62,28 @@ func (ns *Server) GetHealth(ctx context.Context, request *ethpb.HealthRequest) (
 	ctx, cancel := context.WithTimeout(ctx, timeoutDuration)
 	defer cancel() // Important to avoid a context leak
 
-	if ns.SyncChecker.Synced() {
+	// Check optimistic status - validators should not participate when optimistic
+	isOptimistic, err := ns.OptimisticModeFetcher.IsOptimistic(ctx)
+	if err != nil {
+		return &empty.Empty{}, status.Errorf(codes.Internal, "Could not check optimistic status: %v", err)
+	}
+
+	if ns.SyncChecker.Synced() && !isOptimistic {
 		return &empty.Empty{}, nil
 	}
 	if ns.SyncChecker.Syncing() || ns.SyncChecker.Initialized() {
-		if request.SyncingStatus != 0 {
-			// override the 200 success with the provided request status
-			if err := grpc.SetHeader(ctx, metadata.Pairs("x-http-code", strconv.FormatUint(request.SyncingStatus, 10))); err != nil {
-				return &empty.Empty{}, status.Errorf(codes.Internal, "Could not set custom success code header: %v", err)
-			}
-			return &empty.Empty{}, nil
-		}
+		// Set header for REST API clients (via gRPC-gateway)
 		if err := grpc.SetHeader(ctx, metadata.Pairs("x-http-code", strconv.FormatUint(http.StatusPartialContent, 10))); err != nil {
-			return &empty.Empty{}, status.Errorf(codes.Internal, "Could not set custom success code header: %v", err)
+			return &empty.Empty{}, status.Errorf(codes.Internal, "Could not set status code header: %v", err)
 		}
-		return &empty.Empty{}, nil
+		return &empty.Empty{}, status.Error(codes.Unavailable, "node is syncing")
+	}
+	if isOptimistic {
+		// Set header for REST API clients (via gRPC-gateway)
+		if err := grpc.SetHeader(ctx, metadata.Pairs("x-http-code", strconv.FormatUint(http.StatusPartialContent, 10))); err != nil {
+			return &empty.Empty{}, status.Errorf(codes.Internal, "Could not set status code header: %v", err)
+		}
+		return &empty.Empty{}, status.Error(codes.Unavailable, "node is optimistic")
 	}
 	return &empty.Empty{}, status.Errorf(codes.Unavailable, "service unavailable")
 }

beacon-chain/rpc/prysm/v1alpha1/node/server_test.go

@@ -2,6 +2,7 @@ package node
 
 import (
 	"errors"
+	"maps"
 	"testing"
 	"time"
 
@@ -21,6 +22,7 @@ import (
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/reflection"
 	"google.golang.org/protobuf/types/known/emptypb"
 	"google.golang.org/protobuf/types/known/timestamppb"
@@ -187,32 +189,71 @@ func TestNodeServer_GetETH1ConnectionStatus(t *testing.T) {
 	assert.Equal(t, errStr, res.CurrentConnectionError)
 }
 
+// mockServerTransportStream implements grpc.ServerTransportStream for testing
+type mockServerTransportStream struct {
+	headers map[string][]string
+}
+
+func (m *mockServerTransportStream) Method() string { return "" }
+func (m *mockServerTransportStream) SetHeader(md metadata.MD) error {
+	maps.Copy(m.headers, md)
+	return nil
+}
+func (m *mockServerTransportStream) SendHeader(metadata.MD) error { return nil }
+func (m *mockServerTransportStream) SetTrailer(metadata.MD) error { return nil }
+
 func TestNodeServer_GetHealth(t *testing.T) {
 	tests := []struct {
 		name         string
 		input        *mockSync.Sync
-		customStatus uint64
+		isOptimistic bool
 		wantedErr    string
 	}{
 		{
-			name:  "happy path",
-			input: &mockSync.Sync{IsSyncing: false, IsSynced: true},
+			name:         "happy path - synced and not optimistic",
+			input:        &mockSync.Sync{IsSyncing: false, IsSynced: true},
+			isOptimistic: false,
 		},
 		{
-			name:      "syncing",
-			input:     &mockSync.Sync{IsSyncing: false},
-			wantedErr: "service unavailable",
+			name:         "returns error when not synced and not syncing",
+			input:        &mockSync.Sync{IsSyncing: false, IsSynced: false},
+			isOptimistic: false,
+			wantedErr:    "service unavailable",
+		},
+		{
+			name:         "returns error when syncing",
+			input:        &mockSync.Sync{IsSyncing: true, IsSynced: false},
+			isOptimistic: false,
+			wantedErr:    "node is syncing",
+		},
+		{
+			name:         "returns error when synced but optimistic",
+			input:        &mockSync.Sync{IsSyncing: false, IsSynced: true},
+			isOptimistic: true,
+			wantedErr:    "node is optimistic",
+		},
+		{
+			name:         "returns error when syncing and optimistic",
+			input:        &mockSync.Sync{IsSyncing: true, IsSynced: false},
+			isOptimistic: true,
+			wantedErr:    "node is syncing",
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			server := grpc.NewServer()
 			ns := &Server{
-				SyncChecker: tt.input,
+				SyncChecker:           tt.input,
+				OptimisticModeFetcher: &mock.ChainService{Optimistic: tt.isOptimistic},
 			}
 			ethpb.RegisterNodeServer(server, ns)
 			reflection.Register(server)
-			_, err := ns.GetHealth(t.Context(), &ethpb.HealthRequest{SyncingStatus: tt.customStatus})
+
+			// Create context with mock transport stream so grpc.SetHeader works
+			stream := &mockServerTransportStream{headers: make(map[string][]string)}
+			ctx := grpc.NewContextWithServerTransportStream(t.Context(), stream)
+
+			_, err := ns.GetHealth(ctx, &ethpb.HealthRequest{})
 			if tt.wantedErr == "" {
 				require.NoError(t, err)
 				return

beacon-chain/rpc/service.go

@@ -259,18 +259,19 @@ func NewService(ctx context.Context, cfg *Config) *Service {
 	}
 	s.validatorServer = validatorServer
 	nodeServer := &nodev1alpha1.Server{
-		LogsStreamer:         logs.NewStreamServer(),
-		StreamLogsBufferSize: 1000, // Enough to handle bursts of beacon node logs for gRPC streaming.
-		BeaconDB:             s.cfg.BeaconDB,
-		Server:               s.grpcServer,
-		SyncChecker:          s.cfg.SyncService,
-		GenesisTimeFetcher:   s.cfg.GenesisTimeFetcher,
-		PeersFetcher:         s.cfg.PeersFetcher,
-		PeerManager:          s.cfg.PeerManager,
-		GenesisFetcher:       s.cfg.GenesisFetcher,
-		POWChainInfoFetcher:  s.cfg.ExecutionChainInfoFetcher,
-		BeaconMonitoringHost: s.cfg.BeaconMonitoringHost,
-		BeaconMonitoringPort: s.cfg.BeaconMonitoringPort,
+		LogsStreamer:          logs.NewStreamServer(),
+		StreamLogsBufferSize:  1000, // Enough to handle bursts of beacon node logs for gRPC streaming.
+		BeaconDB:              s.cfg.BeaconDB,
+		Server:                s.grpcServer,
+		SyncChecker:           s.cfg.SyncService,
+		GenesisTimeFetcher:    s.cfg.GenesisTimeFetcher,
+		PeersFetcher:          s.cfg.PeersFetcher,
+		PeerManager:           s.cfg.PeerManager,
+		GenesisFetcher:        s.cfg.GenesisFetcher,
+		POWChainInfoFetcher:   s.cfg.ExecutionChainInfoFetcher,
+		BeaconMonitoringHost:  s.cfg.BeaconMonitoringHost,
+		BeaconMonitoringPort:  s.cfg.BeaconMonitoringPort,
+		OptimisticModeFetcher: s.cfg.OptimisticModeFetcher,
 	}
 	beaconChainServer := &beaconv1alpha1.Server{
 		Ctx:                         s.ctx,

changelog/fernantho_connect-merkle-proofs-with-endpoint.md

@@ -0,0 +1,6 @@
+### Added
+
+- Added new proofCollector type to ssz-query
+
+### Ignored
+- Added testing covering the production of Merkle proof from Phase0 beacon state and benchmarked against real Hoodi beacon state (Fulu version)

changelog/james-prysm_grpc-fallback.md

@@ -0,0 +1,7 @@
+### Changed
+
+- gRPC fallback now matches rest api implementation and will also check and connect to only synced nodes.
+
+### Removed
+
+- gRPC resolver for load balancing, the new implementation matches rest api's so we should remove the resolver so it's handled the same way for consistency.

changelog/james-prysm_update-health-endpoint.md

@@ -0,0 +1,3 @@
+### Changed
+
+- gRPC health endpoint will now return an error on syncing or optimistic status showing that it's unavailable.

encoding/bytesutil/integers.go

@@ -163,3 +163,18 @@ func Uint256ToSSZBytes(num string) ([]byte, error) {
 	}
 	return PadTo(ReverseByteOrder(uint256.Bytes()), 32), nil
 }
+
+// PutLittleEndian writes an unsigned integer value in little-endian format.
+// Supports sizes 1, 2, 4, or 8 bytes for uint8/16/32/64 respectively.
+func PutLittleEndian(dst []byte, val uint64, size int) {
+	switch size {
+	case 1:
+		dst[0] = byte(val)
+	case 2:
+		binary.LittleEndian.PutUint16(dst, uint16(val))
+	case 4:
+		binary.LittleEndian.PutUint32(dst, uint32(val))
+	case 8:
+		binary.LittleEndian.PutUint64(dst, val)
+	}
+}

encoding/ssz/query/BUILD.bazel

@@ -9,7 +9,9 @@ go_library(
         "container.go",
         "generalized_index.go",
         "list.go",
+        "merkle_proof.go",
         "path.go",
+        "proof_collector.go",
         "query.go",
         "ssz_info.go",
         "ssz_object.go",
@@ -20,7 +22,12 @@ go_library(
     importpath = "github.com/OffchainLabs/prysm/v7/encoding/ssz/query",
     visibility = ["//visibility:public"],
     deps = [
+        "//container/trie:go_default_library",
+        "//crypto/hash/htr:go_default_library",
+        "//encoding/bytesutil:go_default_library",
         "//encoding/ssz:go_default_library",
+        "//math:go_default_library",
+        "@com_github_prysmaticlabs_fastssz//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
     ],
 )
@@ -29,15 +36,24 @@ go_test(
     name = "go_default_test",
     srcs = [
         "generalized_index_test.go",
+        "merkle_proof_test.go",
         "path_test.go",
+        "proof_collector_test.go",
         "query_test.go",
         "tag_parser_test.go",
     ],
+    embed = [":go_default_library"],
     deps = [
-        ":go_default_library",
+        "//beacon-chain/state/stateutil:go_default_library",
+        "//consensus-types/blocks:go_default_library",
+        "//consensus-types/primitives:go_default_library",
+        "//encoding/ssz:go_default_library",
         "//encoding/ssz/query/testutil:go_default_library",
+        "//proto/prysm/v1alpha1:go_default_library",
         "//proto/ssz_query/testing:go_default_library",
         "//testing/require:go_default_library",
+        "//testing/util:go_default_library",
+        "@com_github_prysmaticlabs_fastssz//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
     ],
 )

encoding/ssz/query/merkle_proof.go

@@ -0,0 +1,34 @@
+package query
+
+import (
+	"fmt"
+	"reflect"
+
+	fastssz "github.com/prysmaticlabs/fastssz"
+)
+
+// Prove is the entrypoint to generate an SSZ Merkle proof for the given generalized index.
+// Parameters:
+// - gindex: the generalized index of the node to prove inclusion for.
+// Returns:
+// - fastssz.Proof: the Merkle proof containing the leaf, index, and sibling hashes.
+// - error: any error encountered during proof generation.
+func (info *SszInfo) Prove(gindex uint64) (*fastssz.Proof, error) {
+	if info == nil {
+		return nil, fmt.Errorf("nil SszInfo")
+	}
+
+	collector := newProofCollector()
+	collector.addTarget(gindex)
+
+	// info.source is guaranteed to be valid and dereferenced by AnalyzeObject
+	v := reflect.ValueOf(info.source).Elem()
+
+	// Start the merkleization and proof collection process.
+	// In SSZ generalized indices, the root is always at index 1.
+	if _, err := collector.merkleize(info, v, 1); err != nil {
+		return nil, err
+	}
+
+	return collector.toProof()
+}

encoding/ssz/query/merkle_proof_test.go

@@ -0,0 +1,163 @@
+package query_test
+
+import (
+	"testing"
+
+	"github.com/OffchainLabs/go-bitfield"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v7/encoding/ssz/query"
+	eth "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+	"github.com/OffchainLabs/prysm/v7/testing/util"
+	ssz "github.com/prysmaticlabs/fastssz"
+)
+
+func TestProve_FixedTestContainer(t *testing.T) {
+	obj := createFixedTestContainer()
+
+	tests := []string{
+		".field_uint32",
+		".nested.value2",
+		".vector_field[3]",
+		".bitvector64_field",
+		".trailing_field",
+	}
+
+	for _, tc := range tests {
+		t.Run(tc, func(t *testing.T) {
+			proveAndVerify(t, obj, tc)
+		})
+	}
+}
+
+func TestProve_VariableTestContainer(t *testing.T) {
+	obj := createVariableTestContainer()
+
+	tests := []string{
+		".leading_field",
+		".field_list_uint64[2]",
+		"len(field_list_uint64)",
+		".nested.nested_list_field[1]",
+		".variable_container_list[0].inner_1.field_list_uint64[1]",
+	}
+
+	for _, tc := range tests {
+		t.Run(tc, func(t *testing.T) {
+			proveAndVerify(t, obj, tc)
+		})
+	}
+}
+
+func TestProve_BeaconBlock(t *testing.T) {
+	randaoReveal := make([]byte, 96)
+	for i := range randaoReveal {
+		randaoReveal[i] = 0x42
+	}
+	root32 := make([]byte, 32)
+	for i := range root32 {
+		root32[i] = 0x24
+	}
+	sig := make([]byte, 96)
+	for i := range sig {
+		sig[i] = 0x99
+	}
+
+	att := &eth.Attestation{
+		AggregationBits: bitfield.Bitlist{0x01},
+		Data: &eth.AttestationData{
+			Slot:            1,
+			CommitteeIndex:  1,
+			BeaconBlockRoot: root32,
+			Source: &eth.Checkpoint{
+				Epoch: 1,
+				Root:  root32,
+			},
+			Target: &eth.Checkpoint{
+				Epoch: 1,
+				Root:  root32,
+			},
+		},
+		Signature: sig,
+	}
+
+	b := util.NewBeaconBlock()
+	b.Block.Slot = 123
+	b.Block.Body.RandaoReveal = randaoReveal
+	b.Block.Body.Attestations = []*eth.Attestation{att}
+
+	sb, err := blocks.NewSignedBeaconBlock(b)
+	require.NoError(t, err)
+
+	protoBlock, err := sb.Block().Proto()
+	require.NoError(t, err)
+
+	obj, ok := protoBlock.(query.SSZObject)
+	require.Equal(t, true, ok, "block proto does not implement query.SSZObject")
+
+	tests := []string{
+		".slot",
+		".body.randao_reveal",
+		".body.attestations[0].data.slot",
+		"len(body.attestations)",
+	}
+
+	for _, tc := range tests {
+		t.Run(tc, func(t *testing.T) {
+			proveAndVerify(t, obj, tc)
+		})
+	}
+}
+
+func TestProve_BeaconState(t *testing.T) {
+	st, _ := util.DeterministicGenesisState(t, 16)
+	require.NoError(t, st.SetSlot(primitives.Slot(42)))
+
+	sszObj, ok := st.ToProtoUnsafe().(query.SSZObject)
+	require.Equal(t, true, ok, "state proto does not implement query.SSZObject")
+
+	tests := []string{
+		".slot",
+		".latest_block_header",
+		".validators[0].effective_balance",
+		"len(validators)",
+	}
+
+	for _, tc := range tests {
+		t.Run(tc, func(t *testing.T) {
+			proveAndVerify(t, sszObj, tc)
+		})
+	}
+}
+
+// proveAndVerify helper to analyze an object, generate a merkle proof for the given path,
+// and verify the proof against the object's root.
+func proveAndVerify(t *testing.T, obj query.SSZObject, pathStr string) {
+	t.Helper()
+
+	info, err := query.AnalyzeObject(obj)
+	require.NoError(t, err)
+
+	path, err := query.ParsePath(pathStr)
+	require.NoError(t, err)
+
+	gi, err := query.GetGeneralizedIndexFromPath(info, path)
+	require.NoError(t, err)
+
+	proof, err := info.Prove(gi)
+	require.NoError(t, err)
+	require.Equal(t, int(gi), proof.Index)
+
+	root, err := obj.HashTreeRoot()
+	require.NoError(t, err)
+
+	ok, err := ssz.VerifyProof(root[:], proof)
+	require.NoError(t, err)
+	require.Equal(t, true, ok, "merkle proof verification failed")
+
+	require.Equal(t, 32, len(proof.Leaf))
+	for i, h := range proof.Hashes {
+		require.Equal(t, 32, len(h), "proof hash %d is not 32 bytes", i)
+	}
+
+}

encoding/ssz/query/proof_collector.go

@@ -0,0 +1,672 @@
+package query
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"math/bits"
+	"reflect"
+	"runtime"
+	"slices"
+	"sync"
+
+	"github.com/OffchainLabs/go-bitfield"
+	"github.com/OffchainLabs/prysm/v7/container/trie"
+	"github.com/OffchainLabs/prysm/v7/crypto/hash/htr"
+	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
+	ssz "github.com/OffchainLabs/prysm/v7/encoding/ssz"
+	"github.com/OffchainLabs/prysm/v7/math"
+	fastssz "github.com/prysmaticlabs/fastssz"
+)
+
+// proofCollector collects sibling hashes and leaves needed for Merkle proofs.
+//
+// Multiproof-ready design:
+// - requiredSiblings/requiredLeaves store which gindices we want to collect (registered before merkleization).
+// - siblings/leaves store the actual collected hashes.
+//
+// Concurrency:
+// - required* maps are read-only during merkleization.
+// - siblings/leaves writes are protected by mutex.
+type proofCollector struct {
+	sync.Mutex
+
+	// Required gindices (registered before merkleization)
+	requiredSiblings map[uint64]struct{}
+	requiredLeaves   map[uint64]struct{}
+
+	// Collected hashes
+	siblings map[uint64][32]byte
+	leaves   map[uint64][32]byte
+}
+
+func newProofCollector() *proofCollector {
+	return &proofCollector{
+		requiredSiblings: make(map[uint64]struct{}),
+		requiredLeaves:   make(map[uint64]struct{}),
+		siblings:         make(map[uint64][32]byte),
+		leaves:           make(map[uint64][32]byte),
+	}
+}
+
+func (pc *proofCollector) reset() {
+	pc.Lock()
+	defer pc.Unlock()
+
+	pc.requiredSiblings = make(map[uint64]struct{})
+	pc.requiredLeaves = make(map[uint64]struct{})
+	pc.siblings = make(map[uint64][32]byte)
+	pc.leaves = make(map[uint64][32]byte)
+}
+
+// addTarget register the target leaf and its required sibling nodes for proof construction.
+// Registration should happen before merkleization begins.
+func (pc *proofCollector) addTarget(gindex uint64) {
+	pc.Lock()
+	defer pc.Unlock()
+
+	pc.requiredLeaves[gindex] = struct{}{}
+
+	// Walk from the target leaf up to (but not including) the root (gindex=1).
+	// At each step, register the sibling node required to prove inclusion.
+	nodeGindex := gindex
+	for nodeGindex > 1 {
+		siblingGindex := nodeGindex ^ 1 // flip the last bit: left<->right sibling
+		pc.requiredSiblings[siblingGindex] = struct{}{}
+
+		// Move to parent
+		nodeGindex /= 2
+	}
+}
+
+// toProof converts the collected siblings and leaves into a fastssz.Proof structure.
+// Current behavior expects a single target leaf (single proof).
+func (pc *proofCollector) toProof() (*fastssz.Proof, error) {
+	pc.Lock()
+	defer pc.Unlock()
+
+	proof := &fastssz.Proof{}
+	if len(pc.leaves) == 0 {
+		return nil, errors.New("no leaves collected: add target leaves before merkleization")
+	}
+
+	leafGindices := make([]uint64, 0, len(pc.leaves))
+	for g := range pc.leaves {
+		leafGindices = append(leafGindices, g)
+	}
+	slices.Sort(leafGindices)
+
+	// single proof resides in leafGindices[0]
+	targetGindex := leafGindices[0]
+	proofIndex, err := math.Int(targetGindex)
+	if err != nil {
+		return nil, fmt.Errorf("gindex %d overflows int: %w", targetGindex, err)
+	}
+	proof.Index = proofIndex
+
+	// store the leaf
+	leaf := pc.leaves[targetGindex]
+	leafBuf := make([]byte, 32)
+	copy(leafBuf, leaf[:])
+	proof.Leaf = leafBuf
+
+	// Walk from target up to root, collecting siblings.
+	steps := bits.Len64(targetGindex) - 1
+	proof.Hashes = make([][]byte, 0, steps)
+
+	for targetGindex > 1 {
+		sib := targetGindex ^ 1
+		h, ok := pc.siblings[sib]
+		if !ok {
+			return nil, fmt.Errorf("missing sibling hash for gindex %d", sib)
+		}
+		proof.Hashes = append(proof.Hashes, h[:])
+		targetGindex /= 2
+	}
+
+	return proof, nil
+}
+
+// collectLeaf checks if the given gindex is a required leaf for the proof,
+// and if so, stores the provided leaf hash in the collector.
+func (pc *proofCollector) collectLeaf(gindex uint64, leaf [32]byte) {
+	if _, ok := pc.requiredLeaves[gindex]; !ok {
+		return
+	}
+	pc.Lock()
+	pc.leaves[gindex] = leaf
+	pc.Unlock()
+}
+
+// collectSibling stores the hash for a sibling node identified by gindex.
+// It only stores the hash if gindex was pre-registered via addTarget (present in requiredSiblings).
+// Writes to the collected siblings map are protected by the collector mutex.
+func (pc *proofCollector) collectSibling(gindex uint64, hash [32]byte) {
+	if _, ok := pc.requiredSiblings[gindex]; !ok {
+		return
+	}
+	pc.Lock()
+	pc.siblings[gindex] = hash
+	pc.Unlock()
+}
+
+// Merkleizers and proof collection methods
+
+// merkleize recursively traverses an SSZ info and computes the Merkle root of the subtree.
+//
+// Proof collection:
+//   - During traversal it calls collectLeaf/collectSibling with the SSZ generalized indices (gindices)
+//     of visited nodes.
+//   - The collector only stores hashes for gindices that were pre-registered via addTarget
+//     (requiredLeaves/requiredSiblings). This makes the traversal multiproof-ready: you can register
+//     multiple targets before calling merkleize.
+//
+// SSZ types handled: basic types, containers, lists, vectors, bitlists, and bitvectors.
+//
+// Parameters:
+// - info: SSZ type metadata for the current value.
+// - v: reflect.Value of the current value.
+// - currentGindex: generalized index of the current subtree root.
+//
+// Returns:
+// - [32]byte: Merkle root of the current subtree.
+// - error: any error encountered during traversal/merkleization.
+func (pc *proofCollector) merkleize(info *SszInfo, v reflect.Value, currentGindex uint64) ([32]byte, error) {
+	if info.sszType.isBasic() {
+		return pc.merkleizeBasicType(info.sszType, v, currentGindex)
+	}
+	switch info.sszType {
+	case Container:
+		return pc.merkleizeContainer(info, v, currentGindex)
+	case List:
+		return pc.merkleizeList(info, v, currentGindex)
+	case Vector:
+		return pc.merkleizeVector(info, v, currentGindex)
+	case Bitlist:
+		return pc.merkleizeBitlist(info, v, currentGindex)
+	case Bitvector:
+		return pc.merkleizeBitvector(info, v, currentGindex)
+	default:
+		return [32]byte{}, fmt.Errorf("unsupported SSZ type: %v", info.sszType)
+	}
+}
+
+// merkleizeBasicType serializes a basic SSZ value into a 32-byte leaf chunk (little-endian, zero-padded).
+//
+// Proof collection:
+// - It calls collectLeaf(currentGindex, leaf) and stores the leaf if currentGindex was pre-registered via addTarget.
+//
+// Parameters:
+// - t: the SSZType (basic).
+// - v: the reflect.Value of the basic value.
+// - currentGindex: the generalized index (gindex) of this leaf.
+//
+// Returns:
+// - [32]byte: the 32-byte SSZ leaf chunk.
+// - error: if the SSZType is not a supported basic type.
+func (pc *proofCollector) merkleizeBasicType(t SSZType, v reflect.Value, currentGindex uint64) ([32]byte, error) {
+	var leaf [32]byte
+
+	// Serialize the value into a 32-byte chunk (little-endian, zero-padded)
+	switch t {
+	case Uint8:
+		leaf[0] = uint8(v.Uint())
+	case Uint16:
+		binary.LittleEndian.PutUint16(leaf[:2], uint16(v.Uint()))
+	case Uint32:
+		binary.LittleEndian.PutUint32(leaf[:4], uint32(v.Uint()))
+	case Uint64:
+		binary.LittleEndian.PutUint64(leaf[:8], v.Uint())
+	case Boolean:
+		if v.Bool() {
+			leaf[0] = 1
+		}
+	default:
+		return [32]byte{}, fmt.Errorf("unexpected basic type: %v", t)
+	}
+
+	pc.collectLeaf(currentGindex, leaf)
+
+	return leaf, nil
+}
+
+// merkleizeContainer computes the Merkle root of an SSZ container by:
+//  1. Merkleizing each field into a 32-byte subtree root
+//  2. Merkleizing the field roots into the container root (padding to the next power-of-2)
+//
+// Generalized indices (gindices): depth = ssz.Depth(uint64(N)) and field i has gindex = (currentGindex << depth) + uint64(i).
+// Proof collection: merkleize() computes each field root, merkleizeVectorAndCollect collects required siblings, and collectLeaf stores the container root if registered.
+//
+// Parameters:
+// - info: SSZ type metadata for the container.
+// - v: reflect.Value of the container value.
+// - currentGindex: generalized index (gindex) of the container root.
+//
+// Returns:
+// - [32]byte: Merkle root of the container.
+// - error: any error encountered while merkleizing fields.
+func (pc *proofCollector) merkleizeContainer(info *SszInfo, v reflect.Value, currentGindex uint64) ([32]byte, error) {
+	// If the container root itself is the target, compute directly and return early.
+	// This avoids full subtree merkleization when we only need the root.
+	if _, ok := pc.requiredLeaves[currentGindex]; ok {
+		root, err := info.HashTreeRoot()
+		if err != nil {
+			return [32]byte{}, err
+		}
+		pc.collectLeaf(currentGindex, root)
+		return root, nil
+	}
+
+	ci, err := info.ContainerInfo()
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	v = dereferencePointer(v)
+
+	// Calculate depth: how many levels from container root to field leaves
+	numFields := len(ci.order)
+	depth := ssz.Depth(uint64(numFields))
+
+	// Step 1: Compute HTR for each subtree (field)
+	fieldRoots := make([][32]byte, numFields)
+
+	for i, name := range ci.order {
+		fieldInfo := ci.fields[name]
+		fieldVal := v.FieldByName(fieldInfo.goFieldName)
+
+		// Field i's gindex: shift currentGindex left by depth, then OR with field index
+		fieldGindex := currentGindex<<depth + uint64(i)
+
+		htr, err := pc.merkleize(fieldInfo.sszInfo, fieldVal, fieldGindex)
+		if err != nil {
+			return [32]byte{}, fmt.Errorf("field %s: %w", name, err)
+		}
+		fieldRoots[i] = htr
+	}
+
+	// Step 2: Merkleize the field hashes into the container root,
+	// collecting sibling hashes if target is within this subtree
+	root := pc.merkleizeVectorAndCollect(fieldRoots, currentGindex, uint64(depth))
+
+	return root, nil
+}
+
+// merkleizeVectorBody computes the Merkle root of the "data" subtree for vector-like SSZ types
+// (vectors and the data-part of lists/bitlists).
+//
+// Generalized indices (gindices): depth = ssz.Depth(limit); leafBase = subtreeRootGindex << depth; element/chunk i gindex = leafBase + uint64(i).
+// Proof collection: merkleize() is called for composite elements; merkleizeVectorAndCollect collects required siblings at this layer.
+// Padding: merkleizeVectorAndCollect uses trie.ZeroHashes as needed.
+//
+// Parameters:
+// - elemInfo: SSZ type metadata for the element.
+// - v: reflect.Value of the vector/list data.
+// - length: number of actual elements present.
+// - limit: virtual leaf capacity used for padding/Depth (fixed length for vectors, limit for lists).
+// - subtreeRootGindex: gindex of the data subtree root.
+//
+// Returns:
+// - [32]byte: Merkle root of the data subtree.
+// - error: any error encountered while merkleizing composite elements.
+func (pc *proofCollector) merkleizeVectorBody(elemInfo *SszInfo, v reflect.Value, length int, limit uint64, subtreeRootGindex uint64) ([32]byte, error) {
+	depth := uint64(ssz.Depth(limit))
+
+	var chunks [][32]byte
+	if elemInfo.sszType.isBasic() {
+		// Serialize basic elements and pack into 32-byte chunks using ssz.PackByChunk.
+		elemSize, err := math.Int(itemLength(elemInfo))
+		if err != nil {
+			return [32]byte{}, fmt.Errorf("element size %d overflows int: %w", itemLength(elemInfo), err)
+		}
+		serialized := make([][]byte, length)
+		// Single contiguous allocation for all element data
+		allData := make([]byte, length*elemSize)
+		for i := range length {
+			buf := allData[i*elemSize : (i+1)*elemSize]
+			elem := v.Index(i)
+			if elemInfo.sszType == Boolean && elem.Bool() {
+				buf[0] = 1
+			} else {
+				bytesutil.PutLittleEndian(buf, elem.Uint(), elemSize)
+			}
+			serialized[i] = buf
+		}
+		chunks, err = ssz.PackByChunk(serialized)
+		if err != nil {
+			return [32]byte{}, err
+		}
+	} else {
+		// Composite elements: compute each element root (no padding here; merkleizeVectorAndCollect pads).
+		chunks = make([][32]byte, length)
+
+		// Fall back to per-element merkleization with proper gindices for proof collection.
+		// Parallel execution
+		workerCount := min(runtime.GOMAXPROCS(0), length)
+
+		jobs := make(chan int, workerCount*16)
+		errCh := make(chan error, 1) // only need the first error
+		stopCh := make(chan struct{})
+		var stopOnce sync.Once
+		var wg sync.WaitGroup
+
+		worker := func() {
+			defer wg.Done()
+			for idx := range jobs {
+				select {
+				case <-stopCh:
+					return
+				default:
+				}
+
+				elemGindex := subtreeRootGindex<<depth + uint64(idx)
+				htr, err := pc.merkleize(elemInfo, v.Index(idx), elemGindex)
+				if err != nil {
+					stopOnce.Do(func() { close(stopCh) })
+					select {
+					case errCh <- fmt.Errorf("index %d: %w", idx, err):
+					default:
+					}
+					return
+				}
+				chunks[idx] = htr
+			}
+		}
+
+		wg.Add(workerCount)
+		for range workerCount {
+			go worker()
+		}
+
+		// Enqueue jobs; stop early if any worker reports an error.
+	enqueue:
+		for i := range length {
+			select {
+			case <-stopCh:
+				break enqueue
+			case jobs <- i:
+			}
+		}
+		close(jobs)
+
+		wg.Wait()
+
+		select {
+		case err := <-errCh:
+			return [32]byte{}, err
+		default:
+		}
+	}
+
+	root := pc.merkleizeVectorAndCollect(chunks, subtreeRootGindex, depth)
+	return root, nil
+}
+
+// merkleizeVector computes the Merkle root of an SSZ vector (fixed-length).
+//
+// Generalized indices (gindices): currentGindex is the gindex of the vector root; element/chunk gindices are derived
+// inside merkleizeVectorBody using leafBase = currentGindex << ssz.Depth(leaves).
+//
+// Proof collection: merkleizeVectorBody performs element/chunk merkleization and collects required siblings at the
+// vector layer; collectLeaf stores the vector root if currentGindex was registered via addTarget.
+//
+// Parameters:
+// - info: SSZ type metadata for the vector.
+// - v: reflect.Value of the vector value.
+// - currentGindex: generalized index (gindex) of the vector root.
+//
+// Returns:
+// - [32]byte: Merkle root of the vector.
+// - error: any error encountered while merkleizing composite elements.
+func (pc *proofCollector) merkleizeVector(info *SszInfo, v reflect.Value, currentGindex uint64) ([32]byte, error) {
+	vi, err := info.VectorInfo()
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	length, err := math.Int(vi.Length())
+	if err != nil {
+		return [32]byte{}, fmt.Errorf("vector length %d overflows int: %w", vi.Length(), err)
+	}
+	elemInfo := vi.element
+
+	// Determine the virtual leaf capacity for the vector.
+	leaves, err := getChunkCount(info)
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	root, err := pc.merkleizeVectorBody(elemInfo, v, length, leaves, currentGindex)
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	// If the vector root itself is the target
+	pc.collectLeaf(currentGindex, root)
+
+	return root, nil
+}
+
+// merkleizeList computes the Merkle root of an SSZ list by merkleizing its data subtree and mixing in the length.
+//
+// Generalized indices (gindices): dataRoot is the left child of the list root (dataRootGindex = currentGindex*2); the length mixin is the right child (currentGindex*2+1).
+// Proof collection: merkleizeVectorBody computes the data root (collecting required siblings in the data subtree), and mixinLengthAndCollect collects required siblings at the length-mixin level; collectLeaf stores the list root if registered.
+//
+// Parameters:
+// - info: SSZ type metadata for the list.
+// - v: reflect.Value of the list value.
+// - currentGindex: generalized index (gindex) of the list root.
+//
+// Returns:
+// - [32]byte: Merkle root of the list.
+// - error: any error encountered while merkleizing the data subtree.
+func (pc *proofCollector) merkleizeList(info *SszInfo, v reflect.Value, currentGindex uint64) ([32]byte, error) {
+	li, err := info.ListInfo()
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	length := v.Len()
+	elemInfo := li.element
+
+	chunks := make([][32]byte, 2)
+	// Compute the length hash (little-endian uint256)
+	binary.LittleEndian.PutUint64(chunks[1][:8], uint64(length))
+
+	// Data subtree root is the left child of the list root.
+	dataRootGindex := currentGindex * 2
+
+	// Compute virtual leaf capacity for the data subtree.
+	leaves, err := getChunkCount(info)
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	chunks[0], err = pc.merkleizeVectorBody(elemInfo, v, length, leaves, dataRootGindex)
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	// Handle the length mixin level (and proof bookkeeping at this level).
+	// Compute the final list root: hash(dataRoot || lengthHash)
+	root := pc.mixinLengthAndCollect(currentGindex, chunks)
+
+	// If the list root itself is the target
+	pc.collectLeaf(currentGindex, root)
+
+	return root, nil
+}
+
+// merkleizeBitvectorBody computes the Merkle root of a bitvector-like byte sequence by packing it into 32-byte chunks
+// and merkleizing those chunks as a fixed-capacity vector (padding with trie.ZeroHashes as needed).
+//
+// Generalized indices (gindices): depth = ssz.Depth(chunkLimit); leafBase = subtreeRootGindex << depth; chunk i uses gindex = leafBase + uint64(i).
+// Proof collection: merkleizeVectorAndCollect collects required sibling hashes at the chunk-merkleization layer.
+//
+// Parameters:
+// - data: raw byte sequence representing the bitvector payload.
+// - chunkLimit: fixed/limit number of 32-byte chunks (used for padding/Depth).
+// - subtreeRootGindex: gindex of the bitvector data subtree root.
+//
+// Returns:
+// - [32]byte: Merkle root of the bitvector data subtree.
+// - error: any error encountered while packing data into chunks.
+func (pc *proofCollector) merkleizeBitvectorBody(data []byte, chunkLimit uint64, subtreeRootGindex uint64) ([32]byte, error) {
+	depth := ssz.Depth(chunkLimit)
+	chunks, err := ssz.PackByChunk([][]byte{data})
+	if err != nil {
+		return [32]byte{}, err
+	}
+	root := pc.merkleizeVectorAndCollect(chunks, subtreeRootGindex, uint64(depth))
+	return root, nil
+}
+
+// merkleizeBitvector computes the Merkle root of a fixed-length SSZ bitvector and collects proof nodes for targets.
+//
+// Parameters:
+// - info: SSZ type metadata for the bitvector.
+// - v: reflect.Value of the bitvector value.
+// - currentGindex: generalized index (gindex) of the bitvector root.
+//
+// Returns:
+// - [32]byte: Merkle root of the bitvector.
+// - error: any error encountered during packing or merkleization.
+func (pc *proofCollector) merkleizeBitvector(info *SszInfo, v reflect.Value, currentGindex uint64) ([32]byte, error) {
+	bitvectorBytes := v.Bytes()
+	if len(bitvectorBytes) == 0 {
+		return [32]byte{}, fmt.Errorf("bitvector field is uninitialized (nil or empty slice)")
+	}
+
+	// Compute virtual leaf capacity for the bitvector.
+	numChunks, err := getChunkCount(info)
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	root, err := pc.merkleizeBitvectorBody(bitvectorBytes, numChunks, currentGindex)
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	pc.collectLeaf(currentGindex, root)
+
+	return root, nil
+}
+
+// merkleizeBitlist computes the Merkle root of an SSZ bitlist by merkleizing its data chunks and mixing in the bit length.
+//
+// Generalized indices (gindices): dataRoot is the left child (dataRootGindex = currentGindex*2) and the length mixin is the right child (currentGindex*2+1).
+// Proof collection: merkleizeBitvectorBody computes the data root (collecting required siblings under dataRootGindex), and mixinLengthAndCollect collects required siblings at the length-mixin level; collectLeaf stores the bitlist root if registered.
+//
+// Parameters:
+// - info: SSZ type metadata for the bitlist.
+// - v: reflect.Value of the bitlist value.
+// - currentGindex: generalized index (gindex) of the bitlist root.
+//
+// Returns:
+// - [32]byte: Merkle root of the bitlist.
+// - error: any error encountered while merkleizing the data subtree.
+func (pc *proofCollector) merkleizeBitlist(info *SszInfo, v reflect.Value, currentGindex uint64) ([32]byte, error) {
+	bi, err := info.BitlistInfo()
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	bitlistBytes := v.Bytes()
+
+	// Use go-bitfield to get bytes with termination bit cleared
+	bl := bitfield.Bitlist(bitlistBytes)
+	data := bl.BytesNoTrim()
+
+	// Get the bit length from bitlistInfo
+	bitLength := bi.Length()
+
+	// Get the chunk limit from getChunkCount
+	limitChunks, err := getChunkCount(info)
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	chunks := make([][32]byte, 2)
+	// Compute the length hash (little-endian uint256)
+	binary.LittleEndian.PutUint64(chunks[1][:8], uint64(bitLength))
+
+	dataRootGindex := currentGindex * 2
+	chunks[0], err = pc.merkleizeBitvectorBody(data, limitChunks, dataRootGindex)
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	// Handle the length mixin level (and proof bookkeeping at this level).
+	root := pc.mixinLengthAndCollect(currentGindex, chunks)
+
+	pc.collectLeaf(currentGindex, root)
+
+	return root, nil
+}
+
+// merkleizeVectorAndCollect merkleizes a slice of 32-byte leaf nodes into a subtree root, padding to a virtual size of 2^depth.
+//
+// Generalized indices (gindices): at layer i (0-based), nodes have gindices levelBase = subtreeGeneralizedIndex << (depth-i) and node gindex = levelBase + idx.
+// Proof collection: for each layer it calls collectSibling(nodeGindex, nodeHash) and stores only those gindices registered via addTarget.
+//
+// Parameters:
+// - elements: leaf-level hashes (may be shorter than 2^depth; padding is applied with trie.ZeroHashes).
+// - subtreeGeneralizedIndex: gindex of the subtree root.
+// - depth: number of merkleization layers from subtree root to leaves.
+//
+// Returns:
+// - [32]byte: Merkle root of the subtree.
+func (pc *proofCollector) merkleizeVectorAndCollect(elements [][32]byte, subtreeGeneralizedIndex uint64, depth uint64) [32]byte {
+	// Return zerohash at depth
+	if len(elements) == 0 {
+		return trie.ZeroHashes[depth]
+	}
+	for i := range depth {
+		layerLen := len(elements)
+		oddNodeLength := layerLen%2 == 1
+		if oddNodeLength {
+			zerohash := trie.ZeroHashes[i]
+			elements = append(elements, zerohash)
+		}
+
+		levelBaseGindex := subtreeGeneralizedIndex << (depth - i)
+		for idx := range elements {
+			gindex := levelBaseGindex + uint64(idx)
+			pc.collectSibling(gindex, elements[idx])
+			pc.collectLeaf(gindex, elements[idx])
+		}
+
+		elements = htr.VectorizedSha256(elements)
+	}
+	return elements[0]
+}
+
+// mixinLengthAndCollect computes the final mix-in root for list/bitlist values:
+//
+//	root = hash(dataRoot, lengthHash)
+//
+// where chunks[0] is dataRoot and chunks[1] is the 32-byte length hash.
+//
+// Generalized indices (gindices): dataRoot is the left child (dataRootGindex = currentGindex*2) and lengthHash is the right child (lengthHashGindex = currentGindex*2+1).
+// Proof collection: it calls collectSibling/collectLeaf for both child gindices; the collector stores them only if they were registered via addTarget.
+//
+// Parameters:
+// - currentGindex: gindex of the parent node (list/bitlist root).
+// - chunks: two 32-byte nodes: [dataRoot, lengthHash].
+//
+// Returns:
+// - [32]byte: mixed-in Merkle root (or zero value on hashing error).
+// - error: any error encountered during hashing.
+func (pc *proofCollector) mixinLengthAndCollect(currentGindex uint64, chunks [][32]byte) [32]byte {
+	dataRoot, lengthHash := chunks[0], chunks[1]
+	dataRootGindex, lengthHashGindex := currentGindex*2, currentGindex*2+1
+
+	pc.collectSibling(dataRootGindex, dataRoot)
+	pc.collectSibling(lengthHashGindex, lengthHash)
+
+	pc.collectLeaf(dataRootGindex, dataRoot)
+	pc.collectLeaf(lengthHashGindex, lengthHash)
+
+	return ssz.MixInLength(dataRoot, lengthHash[:])
+}

encoding/ssz/query/proof_collector_test.go

@@ -0,0 +1,531 @@
+package query
+
+import (
+	"crypto/sha256"
+	"encoding/binary"
+	"reflect"
+	"slices"
+	"testing"
+
+	"github.com/OffchainLabs/go-bitfield"
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/state/stateutil"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
+	ssz "github.com/OffchainLabs/prysm/v7/encoding/ssz"
+	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
+	sszquerypb "github.com/OffchainLabs/prysm/v7/proto/ssz_query/testing"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+)
+
+func TestProofCollector_New(t *testing.T) {
+	pc := newProofCollector()
+
+	require.NotNil(t, pc)
+	require.Equal(t, 0, len(pc.requiredSiblings))
+	require.Equal(t, 0, len(pc.requiredLeaves))
+	require.Equal(t, 0, len(pc.siblings))
+	require.Equal(t, 0, len(pc.leaves))
+}
+
+func TestProofCollector_Reset(t *testing.T) {
+	pc := newProofCollector()
+	pc.requiredSiblings[3] = struct{}{}
+	pc.requiredLeaves[5] = struct{}{}
+	pc.siblings[3] = [32]byte{1}
+	pc.leaves[5] = [32]byte{2}
+
+	pc.reset()
+
+	require.Equal(t, 0, len(pc.requiredSiblings))
+	require.Equal(t, 0, len(pc.requiredLeaves))
+	require.Equal(t, 0, len(pc.siblings))
+	require.Equal(t, 0, len(pc.leaves))
+}
+
+func TestProofCollector_AddTarget(t *testing.T) {
+	pc := newProofCollector()
+	pc.addTarget(5)
+
+	_, hasLeaf := pc.requiredLeaves[5]
+	_, hasSibling4 := pc.requiredSiblings[4]
+	_, hasSibling3 := pc.requiredSiblings[3]
+	_, hasSibling1 := pc.requiredSiblings[1] // GI 1 is the root
+
+	require.Equal(t, true, hasLeaf)
+	require.Equal(t, true, hasSibling4)
+	require.Equal(t, true, hasSibling3)
+	require.Equal(t, false, hasSibling1)
+}
+
+func TestProofCollector_ToProof(t *testing.T) {
+	pc := newProofCollector()
+	pc.addTarget(5)
+
+	leaf := [32]byte{9}
+	sibling4 := [32]byte{4}
+	sibling3 := [32]byte{3}
+
+	pc.collectLeaf(5, leaf)
+	pc.collectSibling(4, sibling4)
+	pc.collectSibling(3, sibling3)
+
+	proof, err := pc.toProof()
+	require.NoError(t, err)
+
+	require.Equal(t, 5, proof.Index)
+	require.DeepEqual(t, leaf[:], proof.Leaf)
+	require.Equal(t, 2, len(proof.Hashes))
+	require.DeepEqual(t, sibling4[:], proof.Hashes[0])
+	require.DeepEqual(t, sibling3[:], proof.Hashes[1])
+}
+
+func TestProofCollector_ToProof_NoLeaves(t *testing.T) {
+	pc := newProofCollector()
+	_, err := pc.toProof()
+	require.NotNil(t, err)
+}
+
+func TestProofCollector_CollectLeaf(t *testing.T) {
+	pc := newProofCollector()
+	leaf := [32]byte{7}
+
+	pc.collectLeaf(10, leaf)
+	require.Equal(t, 0, len(pc.leaves))
+
+	pc.addTarget(10)
+	pc.collectLeaf(10, leaf)
+	stored, ok := pc.leaves[10]
+	require.Equal(t, true, ok)
+	require.Equal(t, leaf, stored)
+}
+
+func TestProofCollector_CollectSibling(t *testing.T) {
+	pc := newProofCollector()
+	hash := [32]byte{5}
+
+	pc.collectSibling(4, hash)
+	require.Equal(t, 0, len(pc.siblings))
+
+	pc.addTarget(5)
+	pc.collectSibling(4, hash)
+	stored, ok := pc.siblings[4]
+	require.Equal(t, true, ok)
+	require.Equal(t, hash, stored)
+}
+
+func TestProofCollector_Merkleize_BasicTypes(t *testing.T) {
+	testCases := []struct {
+		name     string
+		sszType  SSZType
+		value    any
+		expected [32]byte
+	}{
+		{
+			name:    "uint8",
+			sszType: Uint8,
+			value:   uint8(0x11),
+			expected: func() [32]byte {
+				var leaf [32]byte
+				leaf[0] = 0x11
+				return leaf
+			}(),
+		},
+		{
+			name:    "uint16",
+			sszType: Uint16,
+			value:   uint16(0x2211),
+			expected: func() [32]byte {
+				var leaf [32]byte
+				binary.LittleEndian.PutUint16(leaf[:2], 0x2211)
+				return leaf
+			}(),
+		},
+		{
+			name:    "uint32",
+			sszType: Uint32,
+			value:   uint32(0x44332211),
+			expected: func() [32]byte {
+				var leaf [32]byte
+				binary.LittleEndian.PutUint32(leaf[:4], 0x44332211)
+				return leaf
+			}(),
+		},
+		{
+			name:    "uint64",
+			sszType: Uint64,
+			value:   uint64(0x8877665544332211),
+			expected: func() [32]byte {
+				var leaf [32]byte
+				binary.LittleEndian.PutUint64(leaf[:8], 0x8877665544332211)
+				return leaf
+			}(),
+		},
+		{
+			name:    "bool",
+			sszType: Boolean,
+			value:   true,
+			expected: func() [32]byte {
+				var leaf [32]byte
+				leaf[0] = 1
+				return leaf
+			}(),
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			pc := newProofCollector()
+			gindex := uint64(3)
+			pc.addTarget(gindex)
+
+			leaf, err := pc.merkleizeBasicType(tc.sszType, reflect.ValueOf(tc.value), gindex)
+			require.NoError(t, err)
+			require.Equal(t, tc.expected, leaf)
+
+			stored, ok := pc.leaves[gindex]
+			require.Equal(t, true, ok)
+			require.Equal(t, tc.expected, stored)
+		})
+	}
+}
+
+func TestProofCollector_Merkleize_Container(t *testing.T) {
+	container := makeFixedTestContainer()
+
+	info, err := AnalyzeObject(container)
+	require.NoError(t, err)
+
+	pc := newProofCollector()
+	pc.addTarget(1)
+
+	root, err := pc.merkleize(info, reflect.ValueOf(container), 1)
+	require.NoError(t, err)
+
+	expected, err := container.HashTreeRoot()
+	require.NoError(t, err)
+	require.Equal(t, expected, root)
+
+	stored, ok := pc.leaves[1]
+	require.Equal(t, true, ok)
+	require.Equal(t, expected, stored)
+}
+
+func TestProofCollector_Merkleize_Vector(t *testing.T) {
+	container := makeFixedTestContainer()
+	info, err := AnalyzeObject(container)
+	require.NoError(t, err)
+
+	ci, err := info.ContainerInfo()
+	require.NoError(t, err)
+	field := ci.fields["vector_field"]
+
+	pc := newProofCollector()
+	root, err := pc.merkleizeVector(field.sszInfo, reflect.ValueOf(container.VectorField), 1)
+	require.NoError(t, err)
+
+	serialized := make([][]byte, len(container.VectorField))
+	for i, v := range container.VectorField {
+		buf := make([]byte, 8)
+		binary.LittleEndian.PutUint64(buf, v)
+		serialized[i] = buf
+	}
+	chunks, err := ssz.PackByChunk(serialized)
+	require.NoError(t, err)
+	limit, err := getChunkCount(field.sszInfo)
+	require.NoError(t, err)
+	expected := ssz.MerkleizeVector(chunks, limit)
+
+	require.Equal(t, expected, root)
+}
+
+func TestProofCollector_Merkleize_List(t *testing.T) {
+	list := []*sszquerypb.FixedNestedContainer{
+		makeFixedNestedContainer(1),
+		makeFixedNestedContainer(2),
+	}
+	container := makeVariableTestContainer(list, bitfield.NewBitlist(1))
+	info, err := AnalyzeObject(container)
+	require.NoError(t, err)
+
+	ci, err := info.ContainerInfo()
+	require.NoError(t, err)
+	field := ci.fields["field_list_container"]
+
+	pc := newProofCollector()
+	root, err := pc.merkleizeList(field.sszInfo, reflect.ValueOf(list), 1)
+	require.NoError(t, err)
+
+	listInfo, err := field.sszInfo.ListInfo()
+	require.NoError(t, err)
+	expected, err := ssz.MerkleizeListSSZ(list, listInfo.Limit())
+	require.NoError(t, err)
+
+	require.Equal(t, expected, root)
+}
+
+func TestProofCollector_Merkleize_Bitvector(t *testing.T) {
+	container := makeFixedTestContainer()
+	info, err := AnalyzeObject(container)
+	require.NoError(t, err)
+
+	ci, err := info.ContainerInfo()
+	require.NoError(t, err)
+	field := ci.fields["bitvector64_field"]
+
+	pc := newProofCollector()
+	root, err := pc.merkleizeBitvector(field.sszInfo, reflect.ValueOf(container.Bitvector64Field), 1)
+	require.NoError(t, err)
+
+	expected, err := ssz.MerkleizeByteSliceSSZ([]byte(container.Bitvector64Field))
+	require.NoError(t, err)
+	require.Equal(t, expected, root)
+}
+
+func TestProofCollector_Merkleize_Bitlist(t *testing.T) {
+	bitlist := bitfield.NewBitlist(16)
+	bitlist.SetBitAt(3, true)
+	bitlist.SetBitAt(8, true)
+
+	container := makeVariableTestContainer(nil, bitlist)
+	info, err := AnalyzeObject(container)
+	require.NoError(t, err)
+
+	ci, err := info.ContainerInfo()
+	require.NoError(t, err)
+	field := ci.fields["bitlist_field"]
+
+	pc := newProofCollector()
+	root, err := pc.merkleizeBitlist(field.sszInfo, reflect.ValueOf(container.BitlistField), 1)
+	require.NoError(t, err)
+
+	bitlistInfo, err := field.sszInfo.BitlistInfo()
+	require.NoError(t, err)
+	expected, err := ssz.BitlistRoot(bitfield.Bitlist(bitlist), bitlistInfo.Limit())
+	require.NoError(t, err)
+	require.Equal(t, expected, root)
+}
+
+func TestProofCollector_MerkleizeVectorBody_Basic(t *testing.T) {
+	container := makeFixedTestContainer()
+	info, err := AnalyzeObject(container)
+	require.NoError(t, err)
+
+	ci, err := info.ContainerInfo()
+	require.NoError(t, err)
+	field := ci.fields["vector_field"]
+	vectorInfo, err := field.sszInfo.VectorInfo()
+	require.NoError(t, err)
+	length := len(container.VectorField)
+	limit, err := getChunkCount(field.sszInfo)
+	require.NoError(t, err)
+
+	pc := newProofCollector()
+	root, err := pc.merkleizeVectorBody(vectorInfo.element, reflect.ValueOf(container.VectorField), length, limit, 2)
+	require.NoError(t, err)
+
+	serialized := make([][]byte, len(container.VectorField))
+	for i, v := range container.VectorField {
+		buf := make([]byte, 8)
+		binary.LittleEndian.PutUint64(buf, v)
+		serialized[i] = buf
+	}
+	chunks, err := ssz.PackByChunk(serialized)
+	require.NoError(t, err)
+	expected := ssz.MerkleizeVector(chunks, limit)
+
+	require.Equal(t, expected, root)
+}
+
+func TestProofCollector_MerkleizeVectorAndCollect(t *testing.T) {
+	pc := newProofCollector()
+	pc.addTarget(6)
+
+	elements := [][32]byte{{1}, {2}}
+	expected := ssz.MerkleizeVector(slices.Clone(elements), 2)
+	root := pc.merkleizeVectorAndCollect(elements, 3, 1)
+
+	storedLeaf, hasLeaf := pc.leaves[6]
+	storedSibling, hasSibling := pc.siblings[7]
+
+	require.Equal(t, true, hasLeaf)
+	require.Equal(t, true, hasSibling)
+	require.Equal(t, elements[0], storedLeaf)
+	require.Equal(t, elements[1], storedSibling)
+
+	require.Equal(t, expected, root)
+}
+
+func TestProofCollector_MixinLengthAndCollect(t *testing.T) {
+	list := []*sszquerypb.FixedNestedContainer{
+		makeFixedNestedContainer(1),
+		makeFixedNestedContainer(2),
+	}
+	container := makeVariableTestContainer(list, bitfield.NewBitlist(1))
+	info, err := AnalyzeObject(container)
+	require.NoError(t, err)
+
+	ci, err := info.ContainerInfo()
+	require.NoError(t, err)
+	field := ci.fields["field_list_container"]
+
+	// Target gindex 2 (data root) - sibling at gindex 3 (length hash) should be collected
+	pc := newProofCollector()
+	pc.addTarget(2)
+	root, err := pc.merkleizeList(field.sszInfo, reflect.ValueOf(list), 1)
+	require.NoError(t, err)
+
+	listInfo, err := field.sszInfo.ListInfo()
+	require.NoError(t, err)
+	expected, err := ssz.MerkleizeListSSZ(list, listInfo.Limit())
+	require.NoError(t, err)
+	require.Equal(t, expected, root)
+
+	// Verify data root is collected as leaf at gindex 2
+	storedLeaf, hasLeaf := pc.leaves[2]
+	require.Equal(t, true, hasLeaf)
+
+	// Verify length hash is collected as sibling at gindex 3
+	storedSibling, hasSibling := pc.siblings[3]
+	require.Equal(t, true, hasSibling)
+
+	// Verify the root is hash(dataRoot || lengthHash)
+	expectedBuf := append(storedLeaf[:], storedSibling[:]...)
+	expectedRoot := sha256.Sum256(expectedBuf)
+	require.Equal(t, expectedRoot, root)
+}
+
+func BenchmarkOptimizedValidatorRoots(b *testing.B) {
+	validators := make([]*ethpb.Validator, 1000)
+	for i := range validators {
+		validators[i] = makeTestValidator(i)
+	}
+
+	b.ResetTimer()
+	for b.Loop() {
+		_, err := stateutil.OptimizedValidatorRoots(validators)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func BenchmarkProofCollectorMerkleize(b *testing.B) {
+	validators := make([]*ethpb.Validator, 1000)
+	for i := range validators {
+		validators[i] = makeTestValidator(i)
+	}
+
+	info, err := AnalyzeObject(validators[0])
+	require.NoError(b, err)
+
+	b.ResetTimer()
+	for b.Loop() {
+		for _, val := range validators {
+			pc := newProofCollector()
+			v := reflect.ValueOf(val)
+			_, err := pc.merkleize(info, v, 1)
+			if err != nil {
+				b.Fatal(err)
+			}
+		}
+	}
+}
+
+func makeTestValidator(i int) *ethpb.Validator {
+	pubkey := make([]byte, 48)
+	for j := range pubkey {
+		pubkey[j] = byte(i + j)
+	}
+
+	withdrawalCredentials := make([]byte, 32)
+	for j := range withdrawalCredentials {
+		withdrawalCredentials[j] = byte(255 - ((i + j) % 256))
+	}
+
+	return &ethpb.Validator{
+		PublicKey:                  pubkey,
+		WithdrawalCredentials:      withdrawalCredentials,
+		EffectiveBalance:           uint64(32000000000 + i),
+		Slashed:                    i%2 == 0,
+		ActivationEligibilityEpoch: primitives.Epoch(i),
+		ActivationEpoch:            primitives.Epoch(i + 1),
+		ExitEpoch:                  primitives.Epoch(i + 2),
+		WithdrawableEpoch:          primitives.Epoch(i + 3),
+	}
+}
+
+func makeFixedNestedContainer(value uint64) *sszquerypb.FixedNestedContainer {
+	value2 := make([]byte, 32)
+	for i := range value2 {
+		value2[i] = byte(i)
+	}
+	return &sszquerypb.FixedNestedContainer{
+		Value1: value,
+		Value2: value2,
+	}
+}
+
+func makeFixedTestContainer() *sszquerypb.FixedTestContainer {
+	fieldBytes32 := make([]byte, 32)
+	for i := range fieldBytes32 {
+		fieldBytes32[i] = byte(i)
+	}
+
+	vectorField := make([]uint64, 24)
+	for i := range vectorField {
+		vectorField[i] = uint64(i)
+	}
+
+	rows := make([][]byte, 5)
+	for i := range rows {
+		row := make([]byte, 32)
+		for j := range row {
+			row[j] = byte(i) + byte(j)
+		}
+		rows[i] = row
+	}
+
+	bitvector64 := bitfield.NewBitvector64()
+	bitvector64.SetBitAt(1, true)
+	bitvector512 := bitfield.NewBitvector512()
+	bitvector512.SetBitAt(10, true)
+
+	trailing := make([]byte, 56)
+	for i := range trailing {
+		trailing[i] = byte(i)
+	}
+
+	return &sszquerypb.FixedTestContainer{
+		FieldUint32:            1,
+		FieldUint64:            2,
+		FieldBool:              true,
+		FieldBytes32:           fieldBytes32,
+		Nested:                 makeFixedNestedContainer(3),
+		VectorField:            vectorField,
+		TwoDimensionBytesField: rows,
+		Bitvector64Field:       bitvector64,
+		Bitvector512Field:      bitvector512,
+		TrailingField:          trailing,
+	}
+}
+
+func makeVariableTestContainer(list []*sszquerypb.FixedNestedContainer, bitlist bitfield.Bitlist) *sszquerypb.VariableTestContainer {
+	leading := make([]byte, 32)
+	for i := range leading {
+		leading[i] = byte(i)
+	}
+	trailing := make([]byte, 56)
+	for i := range trailing {
+		trailing[i] = byte(255 - i)
+	}
+
+	if bitlist == nil {
+		bitlist = bitfield.NewBitlist(0)
+	}
+
+	return &sszquerypb.VariableTestContainer{
+		LeadingField:       leading,
+		FieldListContainer: list,
+		BitlistField:       bitlist,
+		TrailingField:      trailing,
+	}
+}

encoding/ssz/query/query_test.go

@@ -389,6 +389,7 @@ func TestHashTreeRoot(t *testing.T) {
 			require.NoError(t, err, "HashTreeRoot should not return an error")
 			expectedHashTreeRoot, err := tt.obj.HashTreeRoot()
 			require.NoError(t, err, "HashTreeRoot on original object should not return an error")
+			// Verify the Merkle tree root matches with the SSZ generated HashTreeRoot
 			require.Equal(t, expectedHashTreeRoot, hashTreeRoot, "HashTreeRoot from sszInfo should match original object's HashTreeRoot")
 		})
 	}

testing/validator-mock/validator_client_mock.go

@@ -283,16 +283,16 @@ func (mr *MockValidatorClientMockRecorder) ProposeExit(ctx, in any) *gomock.Call
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "ProposeExit", reflect.TypeOf((*MockValidatorClient)(nil).ProposeExit), ctx, in)
 }
 
-// SetHost mocks base method.
-func (m *MockValidatorClient) SetHost(host string) {
+// SwitchHost mocks base method.
+func (m *MockValidatorClient) SwitchHost(host string) {
 	m.ctrl.T.Helper()
-	m.ctrl.Call(m, "SetHost", host)
+	m.ctrl.Call(m, "SwitchHost", host)
 }
 
-// SetHost indicates an expected call of SetHost.
-func (mr *MockValidatorClientMockRecorder) SetHost(host any) *gomock.Call {
+// SwitchHost indicates an expected call of SwitchHost.
+func (mr *MockValidatorClientMockRecorder) SwitchHost(host any) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "SetHost", reflect.TypeOf((*MockValidatorClient)(nil).SetHost), host)
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "SwitchHost", reflect.TypeOf((*MockValidatorClient)(nil).SwitchHost), host)
 }
 
 // StartEventStream mocks base method.

validator/accounts/BUILD.bazel

@@ -25,6 +25,7 @@ go_library(
     ],
     deps = [
         "//api/grpc:go_default_library",
+        "//api/rest:go_default_library",
         "//beacon-chain/core/blocks:go_default_library",
         "//cmd/validator/flags:go_default_library",
         "//config/fieldparams:go_default_library",

validator/accounts/cli_manager.go

@@ -3,14 +3,13 @@ package accounts
 import (
 	"context"
 	"io"
-	"net/http"
 	"os"
 	"time"
 
 	grpcutil "github.com/OffchainLabs/prysm/v7/api/grpc"
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	"github.com/OffchainLabs/prysm/v7/crypto/bls"
 	"github.com/OffchainLabs/prysm/v7/validator/accounts/wallet"
-	beaconApi "github.com/OffchainLabs/prysm/v7/validator/client/beacon-api"
 	iface "github.com/OffchainLabs/prysm/v7/validator/client/iface"
 	nodeClientFactory "github.com/OffchainLabs/prysm/v7/validator/client/node-client-factory"
 	validatorClientFactory "github.com/OffchainLabs/prysm/v7/validator/client/validator-client-factory"
@@ -77,22 +76,17 @@ func (acm *CLIManager) prepareBeaconClients(ctx context.Context) (*iface.Validat
 	}
 
 	ctx = grpcutil.AppendHeaders(ctx, acm.grpcHeaders)
-	grpcConn, err := grpc.DialContext(ctx, acm.beaconRPCProvider, acm.dialOpts...)
-	if err != nil {
-		return nil, nil, errors.Wrapf(err, "could not dial endpoint %s", acm.beaconRPCProvider)
-	}
-	conn := validatorHelpers.NewNodeConnection(
-		grpcConn,
-		acm.beaconApiEndpoint,
-		validatorHelpers.WithBeaconApiTimeout(acm.beaconApiTimeout),
-	)
 
-	restHandler := beaconApi.NewBeaconApiRestHandler(
-		http.Client{Timeout: acm.beaconApiTimeout},
-		acm.beaconApiEndpoint,
+	conn, err := validatorHelpers.NewNodeConnection(
+		validatorHelpers.WithGRPC(ctx, acm.beaconRPCProvider, acm.dialOpts),
+		validatorHelpers.WithREST(acm.beaconApiEndpoint, rest.WithHttpTimeout(acm.beaconApiTimeout)),
 	)
-	validatorClient := validatorClientFactory.NewValidatorClient(conn, restHandler)
-	nodeClient := nodeClientFactory.NewNodeClient(conn, restHandler)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	validatorClient := validatorClientFactory.NewValidatorClient(conn)
+	nodeClient := nodeClientFactory.NewNodeClient(conn)
 
 	return &validatorClient, &nodeClient, nil
 }

validator/client/BUILD.bazel

@@ -10,7 +10,6 @@ go_library(
         "log.go",
         "log_helpers.go",
         "metrics.go",
-        "multiple_endpoints_grpc_resolver.go",
         "propose.go",
         "registration.go",
         "runner.go",
@@ -29,6 +28,7 @@ go_library(
         "//api/client:go_default_library",
         "//api/client/event:go_default_library",
         "//api/grpc:go_default_library",
+        "//api/rest:go_default_library",
         "//api/server/structs:go_default_library",
         "//async:go_default_library",
         "//async/event:go_default_library",
@@ -58,7 +58,6 @@ go_library(
         "//time/slots:go_default_library",
         "//validator/accounts/iface:go_default_library",
         "//validator/accounts/wallet:go_default_library",
-        "//validator/client/beacon-api:go_default_library",
         "//validator/client/beacon-chain-client-factory:go_default_library",
         "//validator/client/iface:go_default_library",
         "//validator/client/node-client-factory:go_default_library",
@@ -86,13 +85,11 @@ go_library(
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
         "@io_opentelemetry_go_contrib_instrumentation_google_golang_org_grpc_otelgrpc//:go_default_library",
-        "@io_opentelemetry_go_contrib_instrumentation_net_http_otelhttp//:go_default_library",
         "@io_opentelemetry_go_otel_trace//:go_default_library",
         "@org_golang_google_grpc//:go_default_library",
         "@org_golang_google_grpc//codes:go_default_library",
         "@org_golang_google_grpc//credentials:go_default_library",
         "@org_golang_google_grpc//metadata:go_default_library",
-        "@org_golang_google_grpc//resolver:go_default_library",
         "@org_golang_google_grpc//status:go_default_library",
         "@org_golang_google_protobuf//proto:go_default_library",
         "@org_golang_google_protobuf//types/known/emptypb:go_default_library",
@@ -124,6 +121,8 @@ go_test(
     ],
     embed = [":go_default_library"],
     deps = [
+        "//api/grpc:go_default_library",
+        "//api/rest:go_default_library",
         "//api/server/structs:go_default_library",
         "//async/event:go_default_library",
         "//beacon-chain/core/signing:go_default_library",

validator/client/beacon-api/BUILD.bazel

@@ -26,7 +26,6 @@ go_library(
         "propose_exit.go",
         "prysm_beacon_chain_client.go",
         "registration.go",
-        "rest_handler_client.go",
         "state_validators.go",
         "status.go",
         "stream_blocks.go",
@@ -43,6 +42,7 @@ go_library(
         "//api:go_default_library",
         "//api/apiutil:go_default_library",
         "//api/client/event:go_default_library",
+        "//api/rest:go_default_library",
         "//api/server/structs:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
@@ -111,6 +111,7 @@ go_test(
     deps = [
         "//api:go_default_library",
         "//api/apiutil:go_default_library",
+        "//api/rest:go_default_library",
         "//api/server/structs:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
         "//beacon-chain/rpc/eth/shared/testing:go_default_library",

validator/client/beacon-api/beacon_api_beacon_chain_client.go

@@ -5,6 +5,7 @@ import (
 	"reflect"
 	"strconv"
 
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	"github.com/OffchainLabs/prysm/v7/api/server/structs"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
@@ -17,7 +18,7 @@ import (
 
 type beaconApiChainClient struct {
 	fallbackClient          iface.ChainClient
-	jsonRestHandler         RestHandler
+	jsonRestHandler         rest.RestHandler
 	stateValidatorsProvider StateValidatorsProvider
 }
 
@@ -327,7 +328,7 @@ func (c beaconApiChainClient) ValidatorParticipation(ctx context.Context, in *et
 	return nil, errors.New("beaconApiChainClient.ValidatorParticipation is not implemented. To use a fallback client, pass a fallback client as the last argument of NewBeaconApiChainClientWithFallback.")
 }
 
-func NewBeaconApiChainClientWithFallback(jsonRestHandler RestHandler, fallbackClient iface.ChainClient) iface.ChainClient {
+func NewBeaconApiChainClientWithFallback(jsonRestHandler rest.RestHandler, fallbackClient iface.ChainClient) iface.ChainClient {
 	return &beaconApiChainClient{
 		jsonRestHandler:         jsonRestHandler,
 		fallbackClient:          fallbackClient,

validator/client/beacon-api/beacon_api_node_client.go

@@ -5,6 +5,7 @@ import (
 	"net/http"
 	"strconv"
 
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	"github.com/OffchainLabs/prysm/v7/api/server/structs"
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v7/validator/client/iface"
@@ -20,7 +21,7 @@ var (
 
 type beaconApiNodeClient struct {
 	fallbackClient  iface.NodeClient
-	jsonRestHandler RestHandler
+	jsonRestHandler rest.RestHandler
 	genesisProvider GenesisProvider
 }
 
@@ -115,7 +116,7 @@ func (c *beaconApiNodeClient) IsReady(ctx context.Context) bool {
 	return statusCode == http.StatusOK
 }
 
-func NewNodeClientWithFallback(jsonRestHandler RestHandler, fallbackClient iface.NodeClient) iface.NodeClient {
+func NewNodeClientWithFallback(jsonRestHandler rest.RestHandler, fallbackClient iface.NodeClient) iface.NodeClient {
 	b := &beaconApiNodeClient{
 		jsonRestHandler: jsonRestHandler,
 		fallbackClient:  fallbackClient,

validator/client/beacon-api/beacon_api_validator_client.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/OffchainLabs/prysm/v7/api/client/event"
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
 	"github.com/OffchainLabs/prysm/v7/monitoring/tracing/trace"
@@ -22,13 +23,13 @@ type beaconApiValidatorClient struct {
 	genesisProvider         GenesisProvider
 	dutiesProvider          dutiesProvider
 	stateValidatorsProvider StateValidatorsProvider
-	jsonRestHandler         RestHandler
+	jsonRestHandler         rest.RestHandler
 	beaconBlockConverter    BeaconBlockConverter
 	prysmChainClient        iface.PrysmChainClient
 	isEventStreamRunning    bool
 }
 
-func NewBeaconApiValidatorClient(jsonRestHandler RestHandler, opts ...ValidatorClientOpt) iface.ValidatorClient {
+func NewBeaconApiValidatorClient(jsonRestHandler rest.RestHandler, opts ...ValidatorClientOpt) iface.ValidatorClient {
 	c := &beaconApiValidatorClient{
 		genesisProvider:         &beaconApiGenesisProvider{jsonRestHandler: jsonRestHandler},
 		dutiesProvider:          beaconApiDutiesProvider{jsonRestHandler: jsonRestHandler},
@@ -331,6 +332,6 @@ func (c *beaconApiValidatorClient) Host() string {
 	return c.jsonRestHandler.Host()
 }
 
-func (c *beaconApiValidatorClient) SetHost(host string) {
-	c.jsonRestHandler.SetHost(host)
+func (c *beaconApiValidatorClient) SwitchHost(host string) {
+	c.jsonRestHandler.SwitchHost(host)
 }

validator/client/beacon-api/beacon_api_validator_client_test.go

@@ -549,7 +549,7 @@ func TestBeaconApiValidatorClient_Host(t *testing.T) {
 
 	hosts := []string{"http://localhost:8080", "http://localhost:8081"}
 	jsonRestHandler := mock.NewMockJsonRestHandler(ctrl)
-	jsonRestHandler.EXPECT().SetHost(
+	jsonRestHandler.EXPECT().SwitchHost(
 		hosts[0],
 	).Times(1)
 	jsonRestHandler.EXPECT().Host().Return(
@@ -557,17 +557,17 @@ func TestBeaconApiValidatorClient_Host(t *testing.T) {
 	).Times(1)
 
 	validatorClient := beaconApiValidatorClient{jsonRestHandler: jsonRestHandler}
-	validatorClient.SetHost(hosts[0])
+	validatorClient.SwitchHost(hosts[0])
 	host := validatorClient.Host()
 	require.Equal(t, hosts[0], host)
 
-	jsonRestHandler.EXPECT().SetHost(
+	jsonRestHandler.EXPECT().SwitchHost(
 		hosts[1],
 	).Times(1)
 	jsonRestHandler.EXPECT().Host().Return(
 		hosts[1],
 	).Times(1)
-	validatorClient.SetHost(hosts[1])
+	validatorClient.SwitchHost(hosts[1])
 	host = validatorClient.Host()
 	require.Equal(t, hosts[1], host)
 }

validator/client/beacon-api/duties.go

@@ -9,6 +9,7 @@ import (
 	"strconv"
 
 	"github.com/OffchainLabs/prysm/v7/api/apiutil"
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	"github.com/OffchainLabs/prysm/v7/api/server/structs"
 	"github.com/OffchainLabs/prysm/v7/config/params"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
@@ -27,7 +28,7 @@ type dutiesProvider interface {
 }
 
 type beaconApiDutiesProvider struct {
-	jsonRestHandler RestHandler
+	jsonRestHandler rest.RestHandler
 }
 
 type attesterDuty struct {

validator/client/beacon-api/genesis.go

@@ -7,6 +7,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	"github.com/OffchainLabs/prysm/v7/api/server/structs"
 	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
@@ -20,7 +21,7 @@ type GenesisProvider interface {
 }
 
 type beaconApiGenesisProvider struct {
-	jsonRestHandler RestHandler
+	jsonRestHandler rest.RestHandler
 	genesis         *structs.Genesis
 	once            sync.Once
 }

validator/client/beacon-api/mock/json_rest_handler_mock.go

@@ -150,14 +150,14 @@ func (mr *MockRestHandlerMockRecorder) PostSSZ(ctx, endpoint, headers, data any)
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "PostSSZ", reflect.TypeOf((*MockRestHandler)(nil).PostSSZ), ctx, endpoint, headers, data)
 }
 
-// SetHost mocks base method.
-func (m *MockRestHandler) SetHost(host string) {
+// SwitchHost mocks base method.
+func (m *MockRestHandler) SwitchHost(host string) {
 	m.ctrl.T.Helper()
-	m.ctrl.Call(m, "SetHost", host)
+	m.ctrl.Call(m, "SwitchHost", host)
 }
 
-// SetHost indicates an expected call of SetHost.
-func (mr *MockRestHandlerMockRecorder) SetHost(host any) *gomock.Call {
+// SwitchHost indicates an expected call of SwitchHost.
+func (mr *MockRestHandlerMockRecorder) SwitchHost(host any) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "SetHost", reflect.TypeOf((*MockRestHandler)(nil).SetHost), host)
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "SwitchHost", reflect.TypeOf((*MockRestHandler)(nil).SwitchHost), host)
 }

validator/client/beacon-api/prysm_beacon_chain_client.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 
 	"github.com/OffchainLabs/prysm/v7/api/apiutil"
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	"github.com/OffchainLabs/prysm/v7/api/server/structs"
 	validator2 "github.com/OffchainLabs/prysm/v7/consensus-types/validator"
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
@@ -18,7 +19,7 @@ import (
 )
 
 // NewPrysmChainClient returns implementation of iface.PrysmChainClient.
-func NewPrysmChainClient(jsonRestHandler RestHandler, nodeClient iface.NodeClient) iface.PrysmChainClient {
+func NewPrysmChainClient(jsonRestHandler rest.RestHandler, nodeClient iface.NodeClient) iface.PrysmChainClient {
 	return prysmChainClient{
 		jsonRestHandler: jsonRestHandler,
 		nodeClient:      nodeClient,
@@ -26,7 +27,7 @@ func NewPrysmChainClient(jsonRestHandler RestHandler, nodeClient iface.NodeClien
 }
 
 type prysmChainClient struct {
-	jsonRestHandler RestHandler
+	jsonRestHandler rest.RestHandler
 	nodeClient      iface.NodeClient
 }
 

validator/client/beacon-api/rest_handler_client_test.go

@@ -12,13 +12,12 @@ import (
 	"time"
 
 	"github.com/OffchainLabs/prysm/v7/api"
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	"github.com/OffchainLabs/prysm/v7/api/server/structs"
 	"github.com/OffchainLabs/prysm/v7/config/params"
-	"github.com/OffchainLabs/prysm/v7/network/httputil"
 	"github.com/OffchainLabs/prysm/v7/runtime/version"
 	"github.com/OffchainLabs/prysm/v7/testing/assert"
 	"github.com/OffchainLabs/prysm/v7/testing/require"
-	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"github.com/sirupsen/logrus/hooks/test"
 )
@@ -45,10 +44,7 @@ func TestGet(t *testing.T) {
 	server := httptest.NewServer(mux)
 	defer server.Close()
 
-	jsonRestHandler := BeaconApiRestHandler{
-		client: http.Client{Timeout: time.Second * 5},
-		host:   server.URL,
-	}
+	jsonRestHandler := rest.NewRestHandler(http.Client{Timeout: time.Second * 5}, server.URL)
 	resp := &structs.GetGenesisResponse{}
 	require.NoError(t, jsonRestHandler.Get(ctx, endpoint+"?arg1=abc&arg2=def", resp))
 	assert.DeepEqual(t, genesisJson, resp)
@@ -79,10 +75,7 @@ func TestGetSSZ(t *testing.T) {
 		server := httptest.NewServer(mux)
 		defer server.Close()
 
-		jsonRestHandler := BeaconApiRestHandler{
-			client: http.Client{Timeout: time.Second * 5},
-			host:   server.URL,
-		}
+		jsonRestHandler := rest.NewRestHandler(http.Client{Timeout: time.Second * 5}, server.URL)
 
 		body, header, err := jsonRestHandler.GetSSZ(ctx, endpoint)
 		require.NoError(t, err)
@@ -108,10 +101,7 @@ func TestGetSSZ(t *testing.T) {
 		server := httptest.NewServer(mux)
 		defer server.Close()
 
-		jsonRestHandler := BeaconApiRestHandler{
-			client: http.Client{Timeout: time.Second * 5},
-			host:   server.URL,
-		}
+		jsonRestHandler := rest.NewRestHandler(http.Client{Timeout: time.Second * 5}, server.URL)
 
 		body, header, err := jsonRestHandler.GetSSZ(ctx, endpoint)
 		require.NoError(t, err)
@@ -136,10 +126,7 @@ func TestGetSSZ(t *testing.T) {
 		server := httptest.NewServer(mux)
 		defer server.Close()
 
-		jsonRestHandler := BeaconApiRestHandler{
-			client: http.Client{Timeout: time.Second * 5},
-			host:   server.URL,
-		}
+		jsonRestHandler := rest.NewRestHandler(http.Client{Timeout: time.Second * 5}, server.URL)
 
 		_, _, err := jsonRestHandler.GetSSZ(ctx, endpoint)
 		require.NoError(t, err)
@@ -161,7 +148,7 @@ func TestAcceptOverrideSSZ(t *testing.T) {
 		require.NoError(t, err)
 	}))
 	defer srv.Close()
-	c := NewBeaconApiRestHandler(http.Client{Timeout: time.Second * 5}, srv.URL)
+	c := rest.NewRestHandler(http.Client{Timeout: time.Second * 5}, srv.URL)
 	_, _, err := c.GetSSZ(t.Context(), "/test")
 	require.NoError(t, err)
 }
@@ -204,162 +191,12 @@ func TestPost(t *testing.T) {
 	server := httptest.NewServer(mux)
 	defer server.Close()
 
-	jsonRestHandler := BeaconApiRestHandler{
-		client: http.Client{Timeout: time.Second * 5},
-		host:   server.URL,
-	}
+	jsonRestHandler := rest.NewRestHandler(http.Client{Timeout: time.Second * 5}, server.URL)
 	resp := &structs.GetGenesisResponse{}
 	require.NoError(t, jsonRestHandler.Post(ctx, endpoint, headers, bytes.NewBuffer(dataBytes), resp))
 	assert.DeepEqual(t, genesisJson, resp)
 }
 
-func Test_decodeResp(t *testing.T) {
-	type j struct {
-		Foo string `json:"foo"`
-	}
-	t.Run("200 JSON with charset", func(t *testing.T) {
-		body := bytes.Buffer{}
-		r := &http.Response{
-			Status:     "200",
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {"application/json; charset=utf-8"}},
-		}
-		require.NoError(t, decodeResp(r, nil))
-	})
-	t.Run("200 non-JSON", func(t *testing.T) {
-		body := bytes.Buffer{}
-		r := &http.Response{
-			Status:     "200",
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.OctetStreamMediaType}},
-		}
-		require.NoError(t, decodeResp(r, nil))
-	})
-	t.Run("204 non-JSON", func(t *testing.T) {
-		body := bytes.Buffer{}
-		r := &http.Response{
-			Status:     "204",
-			StatusCode: http.StatusNoContent,
-			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.OctetStreamMediaType}},
-		}
-		require.NoError(t, decodeResp(r, nil))
-	})
-	t.Run("500 non-JSON", func(t *testing.T) {
-		body := bytes.Buffer{}
-		_, err := body.WriteString("foo")
-		require.NoError(t, err)
-		r := &http.Response{
-			Status:     "500",
-			StatusCode: http.StatusInternalServerError,
-			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.OctetStreamMediaType}},
-		}
-		err = decodeResp(r, nil)
-		errJson := &httputil.DefaultJsonError{}
-		require.Equal(t, true, errors.As(err, &errJson))
-		assert.Equal(t, http.StatusInternalServerError, errJson.Code)
-		assert.Equal(t, "foo", errJson.Message)
-	})
-	t.Run("200 JSON with resp", func(t *testing.T) {
-		body := bytes.Buffer{}
-		b, err := json.Marshal(&j{Foo: "foo"})
-		require.NoError(t, err)
-		body.Write(b)
-		r := &http.Response{
-			Status:     "200",
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
-		}
-		resp := &j{}
-		require.NoError(t, decodeResp(r, resp))
-		assert.Equal(t, "foo", resp.Foo)
-	})
-	t.Run("200 JSON without resp", func(t *testing.T) {
-		body := bytes.Buffer{}
-		r := &http.Response{
-			Status:     "200",
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
-		}
-		require.NoError(t, decodeResp(r, nil))
-	})
-	t.Run("204 JSON", func(t *testing.T) {
-		body := bytes.Buffer{}
-		r := &http.Response{
-			Status:     "204",
-			StatusCode: http.StatusNoContent,
-			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
-		}
-		require.NoError(t, decodeResp(r, nil))
-	})
-	t.Run("500 JSON", func(t *testing.T) {
-		body := bytes.Buffer{}
-		b, err := json.Marshal(&httputil.DefaultJsonError{Code: http.StatusInternalServerError, Message: "error"})
-		require.NoError(t, err)
-		body.Write(b)
-		r := &http.Response{
-			Status:     "500",
-			StatusCode: http.StatusInternalServerError,
-			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
-		}
-		err = decodeResp(r, nil)
-		errJson := &httputil.DefaultJsonError{}
-		require.Equal(t, true, errors.As(err, &errJson))
-		assert.Equal(t, http.StatusInternalServerError, errJson.Code)
-		assert.Equal(t, "error", errJson.Message)
-	})
-	t.Run("200 JSON cannot decode", func(t *testing.T) {
-		body := bytes.Buffer{}
-		_, err := body.WriteString("foo")
-		require.NoError(t, err)
-		r := &http.Response{
-			Status:     "200",
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
-			Request:    &http.Request{},
-		}
-		resp := &j{}
-		err = decodeResp(r, resp)
-		assert.ErrorContains(t, "failed to decode response body into json", err)
-	})
-	t.Run("500 JSON cannot decode", func(t *testing.T) {
-		body := bytes.Buffer{}
-		_, err := body.WriteString("foo")
-		require.NoError(t, err)
-		r := &http.Response{
-			Status:     "500",
-			StatusCode: http.StatusInternalServerError,
-			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {api.JsonMediaType}},
-			Request:    &http.Request{},
-		}
-		err = decodeResp(r, nil)
-		assert.ErrorContains(t, "failed to decode response body into error json", err)
-	})
-	t.Run("500 not JSON", func(t *testing.T) {
-		body := bytes.Buffer{}
-		_, err := body.WriteString("foo")
-		require.NoError(t, err)
-		r := &http.Response{
-			Status:     "500",
-			StatusCode: http.StatusInternalServerError,
-			Body:       io.NopCloser(&body),
-			Header:     map[string][]string{"Content-Type": {"text/plain"}},
-			Request:    &http.Request{},
-		}
-		err = decodeResp(r, nil)
-		assert.ErrorContains(t, "HTTP request unsuccessful (500: foo)", err)
-	})
-}
-
 func TestGetStatusCode(t *testing.T) {
 	ctx := t.Context()
 	const endpoint = "/eth/v1/node/health"
@@ -401,10 +238,7 @@ func TestGetStatusCode(t *testing.T) {
 			server := httptest.NewServer(mux)
 			defer server.Close()
 
-			jsonRestHandler := BeaconApiRestHandler{
-				client: http.Client{Timeout: time.Second * 5},
-				host:   server.URL,
-			}
+			jsonRestHandler := rest.NewRestHandler(http.Client{Timeout: time.Second * 5}, server.URL)
 
 			statusCode, err := jsonRestHandler.GetStatusCode(ctx, endpoint)
 			require.NoError(t, err)
@@ -413,10 +247,7 @@ func TestGetStatusCode(t *testing.T) {
 	}
 
 	t.Run("returns error on connection failure", func(t *testing.T) {
-		jsonRestHandler := BeaconApiRestHandler{
-			client: http.Client{Timeout: time.Millisecond * 100},
-			host:   "http://localhost:99999", // Invalid port
-		}
+		jsonRestHandler := rest.NewRestHandler(http.Client{Timeout: time.Millisecond * 100}, "http://localhost:99999")
 
 		_, err := jsonRestHandler.GetStatusCode(ctx, endpoint)
 		require.ErrorContains(t, "failed to perform request", err)

validator/client/beacon-api/state_validators.go

@@ -9,6 +9,7 @@ import (
 	"strconv"
 
 	"github.com/OffchainLabs/prysm/v7/api/apiutil"
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	"github.com/OffchainLabs/prysm/v7/api/server/structs"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/pkg/errors"
@@ -21,7 +22,7 @@ type StateValidatorsProvider interface {
 }
 
 type beaconApiStateValidatorsProvider struct {
-	jsonRestHandler RestHandler
+	jsonRestHandler rest.RestHandler
 }
 
 func (c beaconApiStateValidatorsProvider) StateValidators(

validator/client/beacon-chain-client-factory/beacon_chain_client_factory.go

@@ -9,19 +9,17 @@ import (
 	validatorHelpers "github.com/OffchainLabs/prysm/v7/validator/helpers"
 )
 
-func NewChainClient(validatorConn validatorHelpers.NodeConnection, jsonRestHandler beaconApi.RestHandler) iface.ChainClient {
-	grpcClient := grpcApi.NewGrpcChainClient(validatorConn.GetGrpcClientConn())
+func NewChainClient(validatorConn validatorHelpers.NodeConnection) iface.ChainClient {
+	grpcClient := grpcApi.NewGrpcChainClient(validatorConn)
 	if features.Get().EnableBeaconRESTApi {
-		return beaconApi.NewBeaconApiChainClientWithFallback(jsonRestHandler, grpcClient)
-	} else {
-		return grpcClient
+		return beaconApi.NewBeaconApiChainClientWithFallback(validatorConn.GetRestHandler(), grpcClient)
 	}
+	return grpcClient
 }
 
-func NewPrysmChainClient(validatorConn validatorHelpers.NodeConnection, jsonRestHandler beaconApi.RestHandler) iface.PrysmChainClient {
+func NewPrysmChainClient(validatorConn validatorHelpers.NodeConnection) iface.PrysmChainClient {
 	if features.Get().EnableBeaconRESTApi {
-		return beaconApi.NewPrysmChainClient(jsonRestHandler, nodeClientFactory.NewNodeClient(validatorConn, jsonRestHandler))
-	} else {
-		return grpcApi.NewGrpcPrysmChainClient(validatorConn.GetGrpcClientConn())
+		return beaconApi.NewPrysmChainClient(validatorConn.GetRestHandler(), nodeClientFactory.NewNodeClient(validatorConn))
 	}
+	return grpcApi.NewGrpcPrysmChainClient(validatorConn)
 }

validator/client/grpc-api/BUILD.bazel

@@ -4,6 +4,7 @@ go_library(
     name = "go_default_library",
     srcs = [
         "grpc_beacon_chain_client.go",
+        "grpc_client_manager.go",
         "grpc_node_client.go",
         "grpc_prysm_beacon_chain_client.go",
         "grpc_validator_client.go",
@@ -25,6 +26,7 @@ go_library(
         "//proto/eth/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//validator/client/iface:go_default_library",
+        "//validator/helpers:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_golang_protobuf//ptypes/empty",
         "@com_github_pkg_errors//:go_default_library",
@@ -39,6 +41,8 @@ go_test(
     name = "go_default_test",
     size = "small",
     srcs = [
+        "grpc_client_manager_test.go",
+        "grpc_node_client_test.go",
         "grpc_prysm_beacon_chain_client_test.go",
         "grpc_validator_client_test.go",
     ],
@@ -56,7 +60,11 @@ go_test(
         "//testing/util:go_default_library",
         "//testing/validator-mock:go_default_library",
         "//validator/client/iface:go_default_library",
+        "//validator/helpers:go_default_library",
+        "//validator/testing:go_default_library",
+        "@com_github_golang_protobuf//ptypes/empty",
         "@com_github_sirupsen_logrus//hooks/test:go_default_library",
+        "@org_golang_google_grpc//:go_default_library",
         "@org_golang_google_protobuf//types/known/emptypb:go_default_library",
         "@org_uber_go_mock//gomock:go_default_library",
     ],

validator/client/grpc-api/grpc_beacon_chain_client.go

@@ -5,38 +5,42 @@ import (
 
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v7/validator/client/iface"
+	validatorHelpers "github.com/OffchainLabs/prysm/v7/validator/helpers"
 	"github.com/golang/protobuf/ptypes/empty"
-	"google.golang.org/grpc"
 )
 
 type grpcChainClient struct {
-	beaconChainClient ethpb.BeaconChainClient
+	*grpcClientManager[ethpb.BeaconChainClient]
 }
 
 func (c *grpcChainClient) ChainHead(ctx context.Context, in *empty.Empty) (*ethpb.ChainHead, error) {
-	return c.beaconChainClient.GetChainHead(ctx, in)
+	return c.getClient().GetChainHead(ctx, in)
 }
 
 func (c *grpcChainClient) ValidatorBalances(ctx context.Context, in *ethpb.ListValidatorBalancesRequest) (*ethpb.ValidatorBalances, error) {
-	return c.beaconChainClient.ListValidatorBalances(ctx, in)
+	return c.getClient().ListValidatorBalances(ctx, in)
 }
 
 func (c *grpcChainClient) Validators(ctx context.Context, in *ethpb.ListValidatorsRequest) (*ethpb.Validators, error) {
-	return c.beaconChainClient.ListValidators(ctx, in)
+	return c.getClient().ListValidators(ctx, in)
 }
 
 func (c *grpcChainClient) ValidatorQueue(ctx context.Context, in *empty.Empty) (*ethpb.ValidatorQueue, error) {
-	return c.beaconChainClient.GetValidatorQueue(ctx, in)
+	return c.getClient().GetValidatorQueue(ctx, in)
 }
 
 func (c *grpcChainClient) ValidatorPerformance(ctx context.Context, in *ethpb.ValidatorPerformanceRequest) (*ethpb.ValidatorPerformanceResponse, error) {
-	return c.beaconChainClient.GetValidatorPerformance(ctx, in)
+	return c.getClient().GetValidatorPerformance(ctx, in)
 }
 
 func (c *grpcChainClient) ValidatorParticipation(ctx context.Context, in *ethpb.GetValidatorParticipationRequest) (*ethpb.ValidatorParticipationResponse, error) {
-	return c.beaconChainClient.GetValidatorParticipation(ctx, in)
+	return c.getClient().GetValidatorParticipation(ctx, in)
 }
 
-func NewGrpcChainClient(cc grpc.ClientConnInterface) iface.ChainClient {
-	return &grpcChainClient{ethpb.NewBeaconChainClient(cc)}
+// NewGrpcChainClient creates a new gRPC chain client that supports
+// dynamic connection switching via the NodeConnection's GrpcConnectionProvider.
+func NewGrpcChainClient(conn validatorHelpers.NodeConnection) iface.ChainClient {
+	return &grpcChainClient{
+		grpcClientManager: newGrpcClientManager(conn, ethpb.NewBeaconChainClient),
+	}
 }

validator/client/grpc-api/grpc_client_manager.go

@@ -0,0 +1,44 @@
+package grpc_api
+
+import (
+	"sync"
+
+	validatorHelpers "github.com/OffchainLabs/prysm/v7/validator/helpers"
+	"google.golang.org/grpc"
+)
+
+// grpcClientManager handles dynamic gRPC client recreation when the connection changes.
+// It uses generics to work with any gRPC client type.
+type grpcClientManager[T any] struct {
+	mu        sync.Mutex
+	conn      validatorHelpers.NodeConnection
+	client    T
+	lastHost  string
+	newClient func(grpc.ClientConnInterface) T
+}
+
+// newGrpcClientManager creates a new client manager with the given connection and client constructor.
+func newGrpcClientManager[T any](
+	conn validatorHelpers.NodeConnection,
+	newClient func(grpc.ClientConnInterface) T,
+) *grpcClientManager[T] {
+	return &grpcClientManager[T]{
+		conn:      conn,
+		newClient: newClient,
+		client:    newClient(conn.GetGrpcClientConn()),
+		lastHost:  conn.GetGrpcConnectionProvider().CurrentHost(),
+	}
+}
+
+// getClient returns the current client, recreating it if the connection has changed.
+func (m *grpcClientManager[T]) getClient() T {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	currentHost := m.conn.GetGrpcConnectionProvider().CurrentHost()
+	if m.lastHost != currentHost {
+		m.client = m.newClient(m.conn.GetGrpcClientConn())
+		m.lastHost = currentHost
+	}
+	return m.client
+}

validator/client/grpc-api/grpc_client_manager_test.go

@@ -0,0 +1,168 @@
+package grpc_api
+
+import (
+	"sync"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v7/testing/assert"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+	validatorHelpers "github.com/OffchainLabs/prysm/v7/validator/helpers"
+	"google.golang.org/grpc"
+)
+
+// mockProvider implements grpcutil.GrpcConnectionProvider for testing.
+type mockProvider struct {
+	hosts        []string
+	currentIndex int
+	mu           sync.Mutex
+}
+
+func (m *mockProvider) CurrentConn() *grpc.ClientConn { return nil }
+func (m *mockProvider) Hosts() []string               { return m.hosts }
+func (m *mockProvider) Close()                        {}
+
+func (m *mockProvider) CurrentHost() string {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	return m.hosts[m.currentIndex]
+}
+
+func (m *mockProvider) SwitchHost(index int) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.currentIndex = index
+	return nil
+}
+
+// nextHost is a test helper for round-robin simulation (not part of the interface).
+func (m *mockProvider) nextHost() {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.currentIndex = (m.currentIndex + 1) % len(m.hosts)
+}
+
+// testClient is a simple type for testing the generic client manager.
+type testClient struct{ id int }
+
+// testManager creates a manager with client creation counting.
+func testManager(t *testing.T, provider *mockProvider) (*grpcClientManager[*testClient], *int) {
+	conn, err := validatorHelpers.NewNodeConnection(validatorHelpers.WithGRPCProvider(provider))
+	require.NoError(t, err)
+
+	clientCount := new(int)
+	newClient := func(grpc.ClientConnInterface) *testClient {
+		*clientCount++
+		return &testClient{id: *clientCount}
+	}
+
+	manager := newGrpcClientManager(conn, newClient)
+	require.NotNil(t, manager)
+	return manager, clientCount
+}
+
+func TestGrpcClientManager(t *testing.T) {
+	t.Run("tracks host", func(t *testing.T) {
+		provider := &mockProvider{hosts: []string{"host1:4000", "host2:4000"}}
+		manager, count := testManager(t, provider)
+		assert.Equal(t, 1, *count)
+		assert.Equal(t, "host1:4000", manager.lastHost)
+	})
+
+	t.Run("same host returns same client", func(t *testing.T) {
+		provider := &mockProvider{hosts: []string{"host1:4000", "host2:4000"}}
+		manager, count := testManager(t, provider)
+
+		c1, c2, c3 := manager.getClient(), manager.getClient(), manager.getClient()
+		assert.Equal(t, 1, *count)
+		assert.Equal(t, c1, c2)
+		assert.Equal(t, c2, c3)
+	})
+
+	t.Run("host change recreates client", func(t *testing.T) {
+		provider := &mockProvider{hosts: []string{"host1:4000", "host2:4000"}}
+		manager, count := testManager(t, provider)
+
+		c1 := manager.getClient()
+		assert.Equal(t, 1, c1.id)
+
+		provider.nextHost()
+		c2 := manager.getClient()
+		assert.Equal(t, 2, *count)
+		assert.Equal(t, 2, c2.id)
+
+		// Same host again - no recreation
+		c3 := manager.getClient()
+		assert.Equal(t, 2, *count)
+		assert.Equal(t, c2, c3)
+	})
+
+	t.Run("multiple host switches", func(t *testing.T) {
+		provider := &mockProvider{hosts: []string{"host1:4000", "host2:4000", "host3:4000"}}
+		manager, count := testManager(t, provider)
+		assert.Equal(t, 1, *count)
+
+		for expected := 2; expected <= 4; expected++ {
+			provider.nextHost()
+			_ = manager.getClient()
+			assert.Equal(t, expected, *count)
+		}
+	})
+}
+
+func TestGrpcClientManager_Concurrent(t *testing.T) {
+	t.Run("concurrent access same host", func(t *testing.T) {
+		provider := &mockProvider{hosts: []string{"host1:4000", "host2:4000"}}
+		manager, _ := testManager(t, provider)
+
+		var clientCount int
+		var countMu sync.Mutex
+		// Override with thread-safe counter
+		manager.newClient = func(grpc.ClientConnInterface) *testClient {
+			countMu.Lock()
+			clientCount++
+			id := clientCount
+			countMu.Unlock()
+			return &testClient{id: id}
+		}
+		manager.client = manager.newClient(nil)
+		clientCount = 1
+
+		var wg sync.WaitGroup
+		for range 100 {
+			wg.Go(func() { _ = manager.getClient() })
+		}
+		wg.Wait()
+
+		countMu.Lock()
+		assert.Equal(t, 1, clientCount)
+		countMu.Unlock()
+	})
+
+	t.Run("concurrent with host changes", func(t *testing.T) {
+		provider := &mockProvider{hosts: []string{"host1:4000", "host2:4000"}}
+		manager, _ := testManager(t, provider)
+
+		var clientCount int
+		var countMu sync.Mutex
+		manager.newClient = func(grpc.ClientConnInterface) *testClient {
+			countMu.Lock()
+			clientCount++
+			id := clientCount
+			countMu.Unlock()
+			return &testClient{id: id}
+		}
+		manager.client = manager.newClient(nil)
+		clientCount = 1
+
+		var wg sync.WaitGroup
+		for range 50 {
+			wg.Go(func() { _ = manager.getClient() })
+			wg.Go(func() { provider.nextHost() })
+		}
+		wg.Wait()
+
+		countMu.Lock()
+		assert.NotEqual(t, 0, clientCount, "Should have created at least one client")
+		countMu.Unlock()
+	})
+}

validator/client/grpc-api/grpc_node_client.go

@@ -5,8 +5,8 @@ import (
 
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v7/validator/client/iface"
+	validatorHelpers "github.com/OffchainLabs/prysm/v7/validator/helpers"
 	"github.com/golang/protobuf/ptypes/empty"
-	"google.golang.org/grpc"
 )
 
 var (
@@ -14,35 +14,40 @@ var (
 )
 
 type grpcNodeClient struct {
-	nodeClient ethpb.NodeClient
+	*grpcClientManager[ethpb.NodeClient]
 }
 
 func (c *grpcNodeClient) SyncStatus(ctx context.Context, in *empty.Empty) (*ethpb.SyncStatus, error) {
-	return c.nodeClient.GetSyncStatus(ctx, in)
+	return c.getClient().GetSyncStatus(ctx, in)
 }
 
 func (c *grpcNodeClient) Genesis(ctx context.Context, in *empty.Empty) (*ethpb.Genesis, error) {
-	return c.nodeClient.GetGenesis(ctx, in)
+	return c.getClient().GetGenesis(ctx, in)
 }
 
 func (c *grpcNodeClient) Version(ctx context.Context, in *empty.Empty) (*ethpb.Version, error) {
-	return c.nodeClient.GetVersion(ctx, in)
+	return c.getClient().GetVersion(ctx, in)
 }
 
 func (c *grpcNodeClient) Peers(ctx context.Context, in *empty.Empty) (*ethpb.Peers, error) {
-	return c.nodeClient.ListPeers(ctx, in)
+	return c.getClient().ListPeers(ctx, in)
 }
 
 func (c *grpcNodeClient) IsReady(ctx context.Context) bool {
-	_, err := c.nodeClient.GetHealth(ctx, &ethpb.HealthRequest{})
+	// GetHealth returns 200 OK only if node is synced and not optimistic.
+	// otherwise it will throw an error
+	_, err := c.getClient().GetHealth(ctx, &ethpb.HealthRequest{})
 	if err != nil {
-		log.WithError(err).Error("Failed to get health of node")
+		log.WithError(err).Debug("Node is not ready")
 		return false
 	}
 	return true
 }
 
-func NewNodeClient(cc grpc.ClientConnInterface) iface.NodeClient {
-	g := &grpcNodeClient{nodeClient: ethpb.NewNodeClient(cc)}
-	return g
+// NewNodeClient creates a new gRPC node client that supports
+// dynamic connection switching via the NodeConnection's GrpcConnectionProvider.
+func NewNodeClient(conn validatorHelpers.NodeConnection) iface.NodeClient {
+	return &grpcNodeClient{
+		grpcClientManager: newGrpcClientManager(conn, ethpb.NewNodeClient),
+	}
 }

validator/client/grpc-api/grpc_node_client_test.go

@@ -0,0 +1,72 @@
+package grpc_api
+
+import (
+	"errors"
+	"testing"
+
+	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v7/testing/assert"
+	"github.com/OffchainLabs/prysm/v7/testing/mock"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+	validatorHelpers "github.com/OffchainLabs/prysm/v7/validator/helpers"
+	"github.com/golang/protobuf/ptypes/empty"
+	"go.uber.org/mock/gomock"
+	"google.golang.org/grpc"
+)
+
+func TestGrpcNodeClient_IsReady(t *testing.T) {
+	// The IsReady function now relies on GetHealth which returns:
+	// - 200 OK (nil error) only if node is synced AND not optimistic
+	// - 206 Partial Content (error) if syncing or optimistic
+	// - 503 Unavailable (error) if unavailable
+	testCases := []struct {
+		name           string
+		healthErr      error
+		expectedResult bool
+	}{
+		{
+			name:           "returns true when health check succeeds (synced and not optimistic)",
+			healthErr:      nil,
+			expectedResult: true,
+		},
+		{
+			name:           "returns false when health check fails (syncing, optimistic, or unavailable)",
+			healthErr:      errors.New("node not ready"),
+			expectedResult: false,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			ctx := t.Context()
+
+			mockNodeClient := mock.NewMockNodeClient(ctrl)
+
+			// Set up health check expectation
+			mockNodeClient.EXPECT().GetHealth(
+				gomock.Any(),
+				gomock.Any(),
+			).Return(&empty.Empty{}, tc.healthErr)
+
+			// Create a mock provider
+			provider := &mockProvider{hosts: []string{"host1:4000"}}
+			conn, err := validatorHelpers.NewNodeConnection(validatorHelpers.WithGRPCProvider(provider))
+			require.NoError(t, err)
+
+			// Create client with injected mock
+			client := &grpcNodeClient{
+				grpcClientManager: &grpcClientManager[ethpb.NodeClient]{
+					conn:      conn,
+					client:    mockNodeClient,
+					lastHost:  "host1:4000",
+					newClient: func(grpc.ClientConnInterface) ethpb.NodeClient { return mockNodeClient },
+				},
+			}
+
+			result := client.IsReady(ctx)
+			assert.Equal(t, tc.expectedResult, result)
+		})
+	}
+}

validator/client/grpc-api/grpc_prysm_beacon_chain_client.go

@@ -12,9 +12,9 @@ import (
 	eth "github.com/OffchainLabs/prysm/v7/proto/eth/v1"
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v7/validator/client/iface"
+	validatorHelpers "github.com/OffchainLabs/prysm/v7/validator/helpers"
 	"github.com/golang/protobuf/ptypes/empty"
 	"github.com/pkg/errors"
-	"google.golang.org/grpc"
 )
 
 type grpcPrysmChainClient struct {
@@ -95,6 +95,8 @@ func (c *grpcPrysmChainClient) ValidatorPerformance(ctx context.Context, in *eth
 	return c.chainClient.ValidatorPerformance(ctx, in)
 }
 
-func NewGrpcPrysmChainClient(cc grpc.ClientConnInterface) iface.PrysmChainClient {
-	return &grpcPrysmChainClient{chainClient: &grpcChainClient{ethpb.NewBeaconChainClient(cc)}}
+// NewGrpcPrysmChainClient creates a new gRPC Prysm chain client that supports
+// dynamic connection switching via the NodeConnection's GrpcConnectionProvider.
+func NewGrpcPrysmChainClient(conn validatorHelpers.NodeConnection) iface.PrysmChainClient {
+	return &grpcPrysmChainClient{chainClient: NewGrpcChainClient(conn)}
 }

validator/client/grpc-api/grpc_validator_client.go

@@ -14,24 +14,24 @@ import (
 	"github.com/OffchainLabs/prysm/v7/monitoring/tracing/trace"
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v7/validator/client/iface"
+	validatorHelpers "github.com/OffchainLabs/prysm/v7/validator/helpers"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/golang/protobuf/ptypes/empty"
 	"github.com/pkg/errors"
-	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 )
 
 type grpcValidatorClient struct {
-	beaconNodeValidatorClient ethpb.BeaconNodeValidatorClient
-	isEventStreamRunning      bool
+	*grpcClientManager[ethpb.BeaconNodeValidatorClient]
+	isEventStreamRunning bool
 }
 
 func (c *grpcValidatorClient) Duties(ctx context.Context, in *ethpb.DutiesRequest) (*ethpb.ValidatorDutiesContainer, error) {
 	if features.Get().DisableDutiesV2 {
 		return c.getDuties(ctx, in)
 	}
-	dutiesResponse, err := c.beaconNodeValidatorClient.GetDutiesV2(ctx, in)
+	dutiesResponse, err := c.getClient().GetDutiesV2(ctx, in)
 	if err != nil {
 		if status.Code(err) == codes.Unimplemented {
 			log.Warn("GetDutiesV2 returned status code unavailable, falling back to GetDuties")
@@ -47,7 +47,7 @@ func (c *grpcValidatorClient) Duties(ctx context.Context, in *ethpb.DutiesReques
 
 // getDuties is calling the v1 of get duties
 func (c *grpcValidatorClient) getDuties(ctx context.Context, in *ethpb.DutiesRequest) (*ethpb.ValidatorDutiesContainer, error) {
-	dutiesResponse, err := c.beaconNodeValidatorClient.GetDuties(ctx, in)
+	dutiesResponse, err := c.getClient().GetDuties(ctx, in)
 	if err != nil {
 		return nil, errors.Wrap(
 			client.ErrConnectionIssue,
@@ -147,108 +147,108 @@ func toValidatorDutyV2(duty *ethpb.DutiesV2Response_Duty) (*ethpb.ValidatorDuty,
 }
 
 func (c *grpcValidatorClient) CheckDoppelGanger(ctx context.Context, in *ethpb.DoppelGangerRequest) (*ethpb.DoppelGangerResponse, error) {
-	return c.beaconNodeValidatorClient.CheckDoppelGanger(ctx, in)
+	return c.getClient().CheckDoppelGanger(ctx, in)
 }
 
 func (c *grpcValidatorClient) DomainData(ctx context.Context, in *ethpb.DomainRequest) (*ethpb.DomainResponse, error) {
-	return c.beaconNodeValidatorClient.DomainData(ctx, in)
+	return c.getClient().DomainData(ctx, in)
 }
 
 func (c *grpcValidatorClient) AttestationData(ctx context.Context, in *ethpb.AttestationDataRequest) (*ethpb.AttestationData, error) {
-	return c.beaconNodeValidatorClient.GetAttestationData(ctx, in)
+	return c.getClient().GetAttestationData(ctx, in)
 }
 
 func (c *grpcValidatorClient) BeaconBlock(ctx context.Context, in *ethpb.BlockRequest) (*ethpb.GenericBeaconBlock, error) {
-	return c.beaconNodeValidatorClient.GetBeaconBlock(ctx, in)
+	return c.getClient().GetBeaconBlock(ctx, in)
 }
 
 func (c *grpcValidatorClient) FeeRecipientByPubKey(ctx context.Context, in *ethpb.FeeRecipientByPubKeyRequest) (*ethpb.FeeRecipientByPubKeyResponse, error) {
-	return c.beaconNodeValidatorClient.GetFeeRecipientByPubKey(ctx, in)
+	return c.getClient().GetFeeRecipientByPubKey(ctx, in)
 }
 
 func (c *grpcValidatorClient) SyncCommitteeContribution(ctx context.Context, in *ethpb.SyncCommitteeContributionRequest) (*ethpb.SyncCommitteeContribution, error) {
-	return c.beaconNodeValidatorClient.GetSyncCommitteeContribution(ctx, in)
+	return c.getClient().GetSyncCommitteeContribution(ctx, in)
 }
 
 func (c *grpcValidatorClient) SyncMessageBlockRoot(ctx context.Context, in *empty.Empty) (*ethpb.SyncMessageBlockRootResponse, error) {
-	return c.beaconNodeValidatorClient.GetSyncMessageBlockRoot(ctx, in)
+	return c.getClient().GetSyncMessageBlockRoot(ctx, in)
 }
 
 func (c *grpcValidatorClient) SyncSubcommitteeIndex(ctx context.Context, in *ethpb.SyncSubcommitteeIndexRequest) (*ethpb.SyncSubcommitteeIndexResponse, error) {
-	return c.beaconNodeValidatorClient.GetSyncSubcommitteeIndex(ctx, in)
+	return c.getClient().GetSyncSubcommitteeIndex(ctx, in)
 }
 
 func (c *grpcValidatorClient) MultipleValidatorStatus(ctx context.Context, in *ethpb.MultipleValidatorStatusRequest) (*ethpb.MultipleValidatorStatusResponse, error) {
-	return c.beaconNodeValidatorClient.MultipleValidatorStatus(ctx, in)
+	return c.getClient().MultipleValidatorStatus(ctx, in)
 }
 
 func (c *grpcValidatorClient) PrepareBeaconProposer(ctx context.Context, in *ethpb.PrepareBeaconProposerRequest) (*empty.Empty, error) {
-	return c.beaconNodeValidatorClient.PrepareBeaconProposer(ctx, in)
+	return c.getClient().PrepareBeaconProposer(ctx, in)
 }
 
 func (c *grpcValidatorClient) ProposeAttestation(ctx context.Context, in *ethpb.Attestation) (*ethpb.AttestResponse, error) {
-	return c.beaconNodeValidatorClient.ProposeAttestation(ctx, in)
+	return c.getClient().ProposeAttestation(ctx, in)
 }
 
 func (c *grpcValidatorClient) ProposeAttestationElectra(ctx context.Context, in *ethpb.SingleAttestation) (*ethpb.AttestResponse, error) {
-	return c.beaconNodeValidatorClient.ProposeAttestationElectra(ctx, in)
+	return c.getClient().ProposeAttestationElectra(ctx, in)
 }
 
 func (c *grpcValidatorClient) ProposeBeaconBlock(ctx context.Context, in *ethpb.GenericSignedBeaconBlock) (*ethpb.ProposeResponse, error) {
-	return c.beaconNodeValidatorClient.ProposeBeaconBlock(ctx, in)
+	return c.getClient().ProposeBeaconBlock(ctx, in)
 }
 
 func (c *grpcValidatorClient) ProposeExit(ctx context.Context, in *ethpb.SignedVoluntaryExit) (*ethpb.ProposeExitResponse, error) {
-	return c.beaconNodeValidatorClient.ProposeExit(ctx, in)
+	return c.getClient().ProposeExit(ctx, in)
 }
 
 func (c *grpcValidatorClient) StreamBlocksAltair(ctx context.Context, in *ethpb.StreamBlocksRequest) (ethpb.BeaconNodeValidator_StreamBlocksAltairClient, error) {
-	return c.beaconNodeValidatorClient.StreamBlocksAltair(ctx, in)
+	return c.getClient().StreamBlocksAltair(ctx, in)
 }
 
 func (c *grpcValidatorClient) SubmitAggregateSelectionProof(ctx context.Context, in *ethpb.AggregateSelectionRequest, _ primitives.ValidatorIndex, _ uint64) (*ethpb.AggregateSelectionResponse, error) {
-	return c.beaconNodeValidatorClient.SubmitAggregateSelectionProof(ctx, in)
+	return c.getClient().SubmitAggregateSelectionProof(ctx, in)
 }
 
 func (c *grpcValidatorClient) SubmitAggregateSelectionProofElectra(ctx context.Context, in *ethpb.AggregateSelectionRequest, _ primitives.ValidatorIndex, _ uint64) (*ethpb.AggregateSelectionElectraResponse, error) {
-	return c.beaconNodeValidatorClient.SubmitAggregateSelectionProofElectra(ctx, in)
+	return c.getClient().SubmitAggregateSelectionProofElectra(ctx, in)
 }
 
 func (c *grpcValidatorClient) SubmitSignedAggregateSelectionProof(ctx context.Context, in *ethpb.SignedAggregateSubmitRequest) (*ethpb.SignedAggregateSubmitResponse, error) {
-	return c.beaconNodeValidatorClient.SubmitSignedAggregateSelectionProof(ctx, in)
+	return c.getClient().SubmitSignedAggregateSelectionProof(ctx, in)
 }
 
 func (c *grpcValidatorClient) SubmitSignedAggregateSelectionProofElectra(ctx context.Context, in *ethpb.SignedAggregateSubmitElectraRequest) (*ethpb.SignedAggregateSubmitResponse, error) {
-	return c.beaconNodeValidatorClient.SubmitSignedAggregateSelectionProofElectra(ctx, in)
+	return c.getClient().SubmitSignedAggregateSelectionProofElectra(ctx, in)
 }
 
 func (c *grpcValidatorClient) SubmitSignedContributionAndProof(ctx context.Context, in *ethpb.SignedContributionAndProof) (*empty.Empty, error) {
-	return c.beaconNodeValidatorClient.SubmitSignedContributionAndProof(ctx, in)
+	return c.getClient().SubmitSignedContributionAndProof(ctx, in)
 }
 
 func (c *grpcValidatorClient) SubmitSyncMessage(ctx context.Context, in *ethpb.SyncCommitteeMessage) (*empty.Empty, error) {
-	return c.beaconNodeValidatorClient.SubmitSyncMessage(ctx, in)
+	return c.getClient().SubmitSyncMessage(ctx, in)
 }
 
 func (c *grpcValidatorClient) SubmitValidatorRegistrations(ctx context.Context, in *ethpb.SignedValidatorRegistrationsV1) (*empty.Empty, error) {
-	return c.beaconNodeValidatorClient.SubmitValidatorRegistrations(ctx, in)
+	return c.getClient().SubmitValidatorRegistrations(ctx, in)
 }
 
 func (c *grpcValidatorClient) SubscribeCommitteeSubnets(ctx context.Context, in *ethpb.CommitteeSubnetsSubscribeRequest, _ []*ethpb.ValidatorDuty) (*empty.Empty, error) {
-	return c.beaconNodeValidatorClient.SubscribeCommitteeSubnets(ctx, in)
+	return c.getClient().SubscribeCommitteeSubnets(ctx, in)
 }
 
 func (c *grpcValidatorClient) ValidatorIndex(ctx context.Context, in *ethpb.ValidatorIndexRequest) (*ethpb.ValidatorIndexResponse, error) {
-	return c.beaconNodeValidatorClient.ValidatorIndex(ctx, in)
+	return c.getClient().ValidatorIndex(ctx, in)
 }
 
 func (c *grpcValidatorClient) ValidatorStatus(ctx context.Context, in *ethpb.ValidatorStatusRequest) (*ethpb.ValidatorStatusResponse, error) {
-	return c.beaconNodeValidatorClient.ValidatorStatus(ctx, in)
+	return c.getClient().ValidatorStatus(ctx, in)
 }
 
 // Deprecated: Do not use.
 func (c *grpcValidatorClient) WaitForChainStart(ctx context.Context, in *empty.Empty) (*ethpb.ChainStartResponse, error) {
-	stream, err := c.beaconNodeValidatorClient.WaitForChainStart(ctx, in)
+	stream, err := c.getClient().WaitForChainStart(ctx, in)
 	if err != nil {
 		return nil, errors.Wrap(
 			client.ErrConnectionIssue,
@@ -260,13 +260,13 @@ func (c *grpcValidatorClient) WaitForChainStart(ctx context.Context, in *empty.E
 }
 
 func (c *grpcValidatorClient) AssignValidatorToSubnet(ctx context.Context, in *ethpb.AssignValidatorToSubnetRequest) (*empty.Empty, error) {
-	return c.beaconNodeValidatorClient.AssignValidatorToSubnet(ctx, in)
+	return c.getClient().AssignValidatorToSubnet(ctx, in)
 }
 func (c *grpcValidatorClient) AggregatedSigAndAggregationBits(
 	ctx context.Context,
 	in *ethpb.AggregatedSigAndAggregationBitsRequest,
 ) (*ethpb.AggregatedSigAndAggregationBitsResponse, error) {
-	return c.beaconNodeValidatorClient.AggregatedSigAndAggregationBits(ctx, in)
+	return c.getClient().AggregatedSigAndAggregationBits(ctx, in)
 }
 
 func (*grpcValidatorClient) AggregatedSelections(context.Context, []iface.BeaconCommitteeSelection) ([]iface.BeaconCommitteeSelection, error) {
@@ -277,8 +277,12 @@ func (*grpcValidatorClient) AggregatedSyncSelections(context.Context, []iface.Sy
 	return nil, iface.ErrNotSupported
 }
 
-func NewGrpcValidatorClient(cc grpc.ClientConnInterface) iface.ValidatorClient {
-	return &grpcValidatorClient{ethpb.NewBeaconNodeValidatorClient(cc), false}
+// NewGrpcValidatorClient creates a new gRPC validator client that supports
+// dynamic connection switching via the NodeConnection's GrpcConnectionProvider.
+func NewGrpcValidatorClient(conn validatorHelpers.NodeConnection) iface.ValidatorClient {
+	return &grpcValidatorClient{
+		grpcClientManager: newGrpcClientManager(conn, ethpb.NewBeaconNodeValidatorClient),
+	}
 }
 
 func (c *grpcValidatorClient) StartEventStream(ctx context.Context, topics []string, eventsChannel chan<- *eventClient.Event) {
@@ -308,7 +312,7 @@ func (c *grpcValidatorClient) StartEventStream(ctx context.Context, topics []str
 		log.Warn("gRPC only supports the head topic, other topics will be ignored")
 	}
 
-	stream, err := c.beaconNodeValidatorClient.StreamSlots(ctx, &ethpb.StreamSlotsRequest{VerifiedOnly: true})
+	stream, err := c.getClient().StreamSlots(ctx, &ethpb.StreamSlotsRequest{VerifiedOnly: true})
 	if err != nil {
 		eventsChannel <- &eventClient.Event{
 			EventType: eventClient.EventConnectionError,
@@ -374,11 +378,20 @@ func (c *grpcValidatorClient) EventStreamIsRunning() bool {
 	return c.isEventStreamRunning
 }
 
-func (*grpcValidatorClient) Host() string {
-	log.Warn(iface.ErrNotSupported)
-	return ""
+func (c *grpcValidatorClient) Host() string {
+	return c.grpcClientManager.conn.GetGrpcConnectionProvider().CurrentHost()
 }
 
-func (*grpcValidatorClient) SetHost(_ string) {
-	log.Warn(iface.ErrNotSupported)
+func (c *grpcValidatorClient) SwitchHost(host string) {
+	provider := c.grpcClientManager.conn.GetGrpcConnectionProvider()
+	// Find the index of the requested host and switch to it
+	for i, h := range provider.Hosts() {
+		if h == host {
+			if err := provider.SwitchHost(i); err != nil {
+				log.WithError(err).WithField("host", host).Error("Failed to set gRPC host")
+			}
+			return
+		}
+	}
+	log.WithField("host", host).Warn("Requested gRPC host not found in configured endpoints")
 }

validator/client/grpc-api/grpc_validator_client_test.go

@@ -14,8 +14,10 @@ import (
 	"github.com/OffchainLabs/prysm/v7/testing/assert"
 	mock2 "github.com/OffchainLabs/prysm/v7/testing/mock"
 	"github.com/OffchainLabs/prysm/v7/testing/require"
+	validatorTesting "github.com/OffchainLabs/prysm/v7/validator/testing"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 	"go.uber.org/mock/gomock"
+	"google.golang.org/grpc"
 	"google.golang.org/protobuf/types/known/emptypb"
 )
 
@@ -133,7 +135,15 @@ func TestWaitForChainStart_StreamSetupFails(t *testing.T) {
 		gomock.Any(),
 	).Return(nil, errors.New("failed stream"))
 
-	validatorClient := &grpcValidatorClient{beaconNodeValidatorClient, true}
+	validatorClient := &grpcValidatorClient{
+		grpcClientManager: newGrpcClientManager(
+			validatorTesting.MockNodeConnection(),
+			func(_ grpc.ClientConnInterface) eth.BeaconNodeValidatorClient {
+				return beaconNodeValidatorClient
+			},
+		),
+		isEventStreamRunning: true,
+	}
 	_, err := validatorClient.WaitForChainStart(t.Context(), &emptypb.Empty{})
 	want := "could not setup beacon chain ChainStart streaming client"
 	assert.ErrorContains(t, want, err)
@@ -146,7 +156,15 @@ func TestStartEventStream(t *testing.T) {
 	ctrl := gomock.NewController(t)
 	defer ctrl.Finish()
 	beaconNodeValidatorClient := mock2.NewMockBeaconNodeValidatorClient(ctrl)
-	grpcClient := &grpcValidatorClient{beaconNodeValidatorClient, true}
+	grpcClient := &grpcValidatorClient{
+		grpcClientManager: newGrpcClientManager(
+			validatorTesting.MockNodeConnection(),
+			func(_ grpc.ClientConnInterface) eth.BeaconNodeValidatorClient {
+				return beaconNodeValidatorClient
+			},
+		),
+		isEventStreamRunning: true,
+	}
 	tests := []struct {
 		name    string
 		topics  []string

validator/client/iface/validator_client.go

@@ -152,5 +152,5 @@ type ValidatorClient interface {
 	AggregatedSelections(ctx context.Context, selections []BeaconCommitteeSelection) ([]BeaconCommitteeSelection, error)
 	AggregatedSyncSelections(ctx context.Context, selections []SyncCommitteeSelection) ([]SyncCommitteeSelection, error)
 	Host() string
-	SetHost(host string)
+	SwitchHost(host string)
 }

validator/client/multiple_endpoints_grpc_resolver.go

@@ -1,53 +0,0 @@
-package client
-
-import (
-	"strings"
-
-	"google.golang.org/grpc/resolver"
-)
-
-// Modification of a default grpc passthrough resolver (google.golang.org/grpc/resolver/passthrough) allowing to use multiple addresses
-// in grpc endpoint. Example:
-// conn, err := grpc.DialContext(ctx, "127.0.0.1:4000,127.0.0.1:4001", grpc.WithInsecure(), grpc.WithResolvers(&multipleEndpointsGrpcResolverBuilder{}))
-// It can be used with any grpc load balancer (pick_first, round_robin). Default is pick_first.
-// Round robin can be used by adding the following option:
-// grpc.WithDefaultServiceConfig("{\"loadBalancingConfig\":[{\"round_robin\":{}}]}")
-type multipleEndpointsGrpcResolverBuilder struct{}
-
-// Build creates and starts multiple endpoints resolver.
-func (*multipleEndpointsGrpcResolverBuilder) Build(target resolver.Target, cc resolver.ClientConn, _ resolver.BuildOptions) (resolver.Resolver, error) {
-	r := &multipleEndpointsGrpcResolver{
-		target: target,
-		cc:     cc,
-	}
-	r.start()
-	return r, nil
-}
-
-// Scheme returns default scheme.
-func (*multipleEndpointsGrpcResolverBuilder) Scheme() string {
-	return resolver.GetDefaultScheme()
-}
-
-type multipleEndpointsGrpcResolver struct {
-	target resolver.Target
-	cc     resolver.ClientConn
-}
-
-func (r *multipleEndpointsGrpcResolver) start() {
-	ep := r.target.Endpoint()
-	endpoints := strings.Split(ep, ",")
-	var addrs []resolver.Address
-	for _, endpoint := range endpoints {
-		addrs = append(addrs, resolver.Address{Addr: endpoint, ServerName: endpoint})
-	}
-	if err := r.cc.UpdateState(resolver.State{Addresses: addrs}); err != nil {
-		log.WithError(err).Error("Failed to update grpc connection state")
-	}
-}
-
-// ResolveNow --
-func (*multipleEndpointsGrpcResolver) ResolveNow(_ resolver.ResolveNowOptions) {}
-
-// Close --
-func (*multipleEndpointsGrpcResolver) Close() {}

validator/client/node-client-factory/node_client_factory.go

@@ -8,11 +8,10 @@ import (
 	validatorHelpers "github.com/OffchainLabs/prysm/v7/validator/helpers"
 )
 
-func NewNodeClient(validatorConn validatorHelpers.NodeConnection, jsonRestHandler beaconApi.RestHandler) iface.NodeClient {
-	grpcClient := grpcApi.NewNodeClient(validatorConn.GetGrpcClientConn())
+func NewNodeClient(validatorConn validatorHelpers.NodeConnection) iface.NodeClient {
+	grpcClient := grpcApi.NewNodeClient(validatorConn)
 	if features.Get().EnableBeaconRESTApi {
-		return beaconApi.NewNodeClientWithFallback(jsonRestHandler, grpcClient)
-	} else {
-		return grpcClient
+		return beaconApi.NewNodeClientWithFallback(validatorConn.GetRestHandler(), grpcClient)
 	}
+	return grpcClient
 }

validator/client/service.go

@@ -2,13 +2,11 @@ package client
 
 import (
 	"context"
-	"net/http"
-	"strings"
 	"time"
 
-	api "github.com/OffchainLabs/prysm/v7/api/client"
 	eventClient "github.com/OffchainLabs/prysm/v7/api/client/event"
 	grpcutil "github.com/OffchainLabs/prysm/v7/api/grpc"
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	"github.com/OffchainLabs/prysm/v7/async/event"
 	lruwrpr "github.com/OffchainLabs/prysm/v7/cache/lru"
 	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
@@ -17,7 +15,6 @@ import (
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v7/validator/accounts/wallet"
-	beaconApi "github.com/OffchainLabs/prysm/v7/validator/client/beacon-api"
 	beaconChainClientFactory "github.com/OffchainLabs/prysm/v7/validator/client/beacon-chain-client-factory"
 	"github.com/OffchainLabs/prysm/v7/validator/client/iface"
 	nodeclientfactory "github.com/OffchainLabs/prysm/v7/validator/client/node-client-factory"
@@ -35,7 +32,6 @@ import (
 	grpcprometheus "github.com/grpc-ecosystem/go-grpc-prometheus"
 	"github.com/pkg/errors"
 	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
-	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/protobuf/proto"
@@ -72,6 +68,7 @@ type Config struct {
 	DB                      db.Database
 	Wallet                  *wallet.Wallet
 	WalletInitializedFeed   *event.Feed
+	Conn                    validatorHelpers.NodeConnection // Optional: pre-built connection (if nil, built from endpoint configs)
 	MaxHealthChecks         int
 	GRPCMaxCallRecvMsgSize  int
 	GRPCRetries             uint
@@ -122,6 +119,12 @@ func NewValidatorService(ctx context.Context, cfg *Config) (*ValidatorService, e
 		maxHealthChecks:         cfg.MaxHealthChecks,
 	}
 
+	// Use pre-built connection if provided
+	if cfg.Conn != nil {
+		s.conn = cfg.Conn
+		return s, nil
+	}
+
 	dialOpts := ConstructDialOptions(
 		cfg.GRPCMaxCallRecvMsgSize,
 		cfg.BeaconNodeCert,
@@ -134,19 +137,21 @@ func NewValidatorService(ctx context.Context, cfg *Config) (*ValidatorService, e
 
 	s.ctx = grpcutil.AppendHeaders(ctx, cfg.GRPCHeaders)
 
-	grpcConn, err := grpc.DialContext(ctx, cfg.BeaconNodeGRPCEndpoint, dialOpts...)
+	conn, err := validatorHelpers.NewNodeConnection(
+		validatorHelpers.WithGRPC(s.ctx, cfg.BeaconNodeGRPCEndpoint, dialOpts),
+		validatorHelpers.WithREST(cfg.BeaconApiEndpoint,
+			rest.WithHttpHeaders(cfg.BeaconApiHeaders),
+			rest.WithHttpTimeout(cfg.BeaconApiTimeout),
+			rest.WithTracing(),
+		),
+	)
 	if err != nil {
 		return s, err
 	}
-	if cfg.BeaconNodeCert != "" {
+	if cfg.BeaconNodeCert != "" && cfg.BeaconNodeGRPCEndpoint != "" {
 		log.Info("Established secure gRPC connection")
 	}
-	s.conn = validatorHelpers.NewNodeConnection(
-		grpcConn,
-		cfg.BeaconApiEndpoint,
-		validatorHelpers.WithBeaconApiHeaders(cfg.BeaconApiHeaders),
-		validatorHelpers.WithBeaconApiTimeout(cfg.BeaconApiTimeout),
-	)
+	s.conn = conn
 
 	return s, nil
 }
@@ -181,20 +186,13 @@ func (v *ValidatorService) Start() {
 		return
 	}
 
-	u := strings.ReplaceAll(v.conn.GetBeaconApiUrl(), " ", "")
-	hosts := strings.Split(u, ",")
-	if len(hosts) == 0 {
-		log.WithError(err).Error("No API hosts provided")
+	restProvider := v.conn.GetRestConnectionProvider()
+	if restProvider == nil || len(restProvider.Hosts()) == 0 {
+		log.Error("No REST API hosts provided")
 		return
 	}
 
-	headersTransport := api.NewCustomHeadersTransport(http.DefaultTransport, v.conn.GetBeaconApiHeaders())
-	restHandler := beaconApi.NewBeaconApiRestHandler(
-		http.Client{Timeout: v.conn.GetBeaconApiTimeout(), Transport: otelhttp.NewTransport(headersTransport)},
-		hosts[0],
-	)
-
-	validatorClient := validatorclientfactory.NewValidatorClient(v.conn, restHandler)
+	validatorClient := validatorclientfactory.NewValidatorClient(v.conn)
 
 	v.validator = &validator{
 		slotFeed:                       new(event.Feed),
@@ -208,12 +206,12 @@ func (v *ValidatorService) Start() {
 		graffiti:                       v.graffiti,
 		graffitiStruct:                 v.graffitiStruct,
 		graffitiOrderedIndex:           graffitiOrderedIndex,
-		beaconNodeHosts:                hosts,
+		conn:                           v.conn,
 		currentHostIndex:               0,
 		validatorClient:                validatorClient,
-		chainClient:                    beaconChainClientFactory.NewChainClient(v.conn, restHandler),
-		nodeClient:                     nodeclientfactory.NewNodeClient(v.conn, restHandler),
-		prysmChainClient:               beaconChainClientFactory.NewPrysmChainClient(v.conn, restHandler),
+		chainClient:                    beaconChainClientFactory.NewChainClient(v.conn),
+		nodeClient:                     nodeclientfactory.NewNodeClient(v.conn),
+		prysmChainClient:               beaconChainClientFactory.NewPrysmChainClient(v.conn),
 		db:                             v.db,
 		km:                             nil,
 		web3SignerConfig:               v.web3SignerConfig,
@@ -369,7 +367,6 @@ func ConstructDialOptions(
 			grpcprometheus.StreamClientInterceptor,
 			grpcretry.StreamClientInterceptor(),
 		),
-		grpc.WithResolvers(&multipleEndpointsGrpcResolverBuilder{}),
 	}
 
 	dialOpts = append(dialOpts, extraOpts...)

validator/client/service_test.go

@@ -33,7 +33,10 @@ func TestStop_CancelsContext(t *testing.T) {
 
 func TestNew_Insecure(t *testing.T) {
 	hook := logTest.NewGlobal()
-	_, err := NewValidatorService(t.Context(), &Config{})
+	_, err := NewValidatorService(t.Context(), &Config{
+		BeaconNodeGRPCEndpoint: "localhost:4000",
+		BeaconApiEndpoint:      "http://localhost:3500",
+	})
 	require.NoError(t, err)
 	require.LogsContain(t, hook, "You are using an insecure gRPC connection")
 }
@@ -58,7 +61,11 @@ func TestStart_GrpcHeaders(t *testing.T) {
 			"Authorization", "this is a valid value",
 		},
 	} {
-		cfg := &Config{GRPCHeaders: strings.Split(input, ",")}
+		cfg := &Config{
+			BeaconNodeGRPCEndpoint: "localhost:4000",
+			BeaconApiEndpoint:      "http://localhost:3500",
+			GRPCHeaders:            strings.Split(input, ","),
+		}
 		validatorService, err := NewValidatorService(ctx, cfg)
 		require.NoError(t, err)
 		md, _ := metadata.FromOutgoingContext(validatorService.ctx)

validator/client/validator-client-factory/validator_client_factory.go

@@ -10,12 +10,10 @@ import (
 
 func NewValidatorClient(
 	validatorConn validatorHelpers.NodeConnection,
-	jsonRestHandler beaconApi.RestHandler,
 	opt ...beaconApi.ValidatorClientOpt,
 ) iface.ValidatorClient {
 	if features.Get().EnableBeaconRESTApi {
-		return beaconApi.NewBeaconApiValidatorClient(jsonRestHandler, opt...)
-	} else {
-		return grpcApi.NewGrpcValidatorClient(validatorConn.GetGrpcClientConn())
+		return beaconApi.NewBeaconApiValidatorClient(validatorConn.GetRestHandler(), opt...)
 	}
+	return grpcApi.NewGrpcValidatorClient(validatorConn)
 }

validator/client/validator.go

@@ -38,6 +38,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/validator/db"
 	dbCommon "github.com/OffchainLabs/prysm/v7/validator/db/common"
 	"github.com/OffchainLabs/prysm/v7/validator/graffiti"
+	validatorHelpers "github.com/OffchainLabs/prysm/v7/validator/helpers"
 	"github.com/OffchainLabs/prysm/v7/validator/keymanager"
 	"github.com/OffchainLabs/prysm/v7/validator/keymanager/local"
 	remoteweb3signer "github.com/OffchainLabs/prysm/v7/validator/keymanager/remote-web3signer"
@@ -101,9 +102,9 @@ type validator struct {
 	pubkeyToStatus                     map[[fieldparams.BLSPubkeyLength]byte]*validatorStatus
 	wallet                             *wallet.Wallet
 	walletInitializedChan              chan *wallet.Wallet
-	currentHostIndex                   uint64
 	walletInitializedFeed              *event.Feed
 	graffitiOrderedIndex               uint64
+	conn                               validatorHelpers.NodeConnection
 	submittedAtts                      map[submittedAttKey]*submittedAtt
 	validatorsRegBatchSize             int
 	validatorClient                    iface.ValidatorClient
@@ -114,7 +115,7 @@ type validator struct {
 	km                                 keymanager.IKeymanager
 	accountChangedSub                  event.Subscription
 	ticker                             slots.Ticker
-	beaconNodeHosts                    []string
+	currentHostIndex                   uint64
 	genesisTime                        time.Time
 	graffiti                           []byte
 	voteStats                          voteStats
@@ -1311,34 +1312,64 @@ func (v *validator) Host() string {
 }
 
 func (v *validator) changeHost() {
-	next := (v.currentHostIndex + 1) % uint64(len(v.beaconNodeHosts))
+	hosts := v.hosts()
+	if len(hosts) <= 1 {
+		return
+	}
+	next := (v.currentHostIndex + 1) % uint64(len(hosts))
 	log.WithFields(logrus.Fields{
-		"currentHost": v.beaconNodeHosts[v.currentHostIndex],
-		"nextHost":    v.beaconNodeHosts[next],
+		"currentHost": hosts[v.currentHostIndex],
+		"nextHost":    hosts[next],
 	}).Warn("Beacon node is not responding, switching host")
-	v.validatorClient.SetHost(v.beaconNodeHosts[next])
+	v.validatorClient.SwitchHost(hosts[next])
 	v.currentHostIndex = next
 }
 
+// hosts returns the list of configured beacon node hosts.
+func (v *validator) hosts() []string {
+	if features.Get().EnableBeaconRESTApi {
+		return v.conn.GetRestConnectionProvider().Hosts()
+	}
+	return v.conn.GetGrpcConnectionProvider().Hosts()
+}
+
+// numHosts returns the number of configured beacon node hosts.
+func (v *validator) numHosts() int {
+	return len(v.hosts())
+}
+
 func (v *validator) FindHealthyHost(ctx context.Context) bool {
-	// Tail-recursive closure keeps retry count private.
-	var check func(remaining int) bool
-	check = func(remaining int) bool {
-		if v.nodeClient.IsReady(ctx) { // ready → done
+	numHosts := v.numHosts()
+	startingHost := v.Host()
+	attemptedHosts := []string{}
+
+	// Check all hosts for a fully synced node
+	for i := range numHosts {
+		if v.nodeClient.IsReady(ctx) {
+			if len(attemptedHosts) > 0 {
+				log.WithFields(logrus.Fields{
+					"previousHost":   startingHost,
+					"newHost":        v.Host(),
+					"failedAttempts": attemptedHosts,
+				}).Info("Failover succeeded: connected to healthy beacon node")
+			}
 			return true
 		}
-		if len(v.beaconNodeHosts) == 1 && features.Get().EnableBeaconRESTApi {
-			log.WithField("host", v.Host()).Warn("Beacon node is not responding, no backup node configured")
-			return false
+		log.WithField("host", v.Host()).Debug("Beacon node not fully synced")
+		attemptedHosts = append(attemptedHosts, v.Host())
+
+		// Try next host if not the last iteration
+		if i < numHosts-1 {
+			v.changeHost()
 		}
-		if remaining == 0 || !features.Get().EnableBeaconRESTApi {
-			return false // exhausted or REST disabled
-		}
-		v.changeHost()
-		return check(remaining - 1) // recurse
 	}
 
-	return check(len(v.beaconNodeHosts))
+	if numHosts == 1 {
+		log.WithField("host", v.Host()).Warn("Beacon node is not fully synced, no backup node configured")
+	} else {
+		log.Warn("No fully synced beacon node found")
+	}
+	return false
 }
 
 func (v *validator) filterAndCacheActiveKeys(ctx context.Context, pubkeys [][fieldparams.BLSPubkeyLength]byte, slot primitives.Slot) ([][fieldparams.BLSPubkeyLength]byte, error) {

validator/client/validator_test.go

@@ -16,6 +16,8 @@ import (
 	"testing"
 	"time"
 
+	grpcutil "github.com/OffchainLabs/prysm/v7/api/grpc"
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	"github.com/OffchainLabs/prysm/v7/api/server/structs"
 	"github.com/OffchainLabs/prysm/v7/async/event"
 	"github.com/OffchainLabs/prysm/v7/cmd/validator/flags"
@@ -37,6 +39,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/validator/accounts/wallet"
 	"github.com/OffchainLabs/prysm/v7/validator/client/iface"
 	dbTest "github.com/OffchainLabs/prysm/v7/validator/db/testing"
+	validatorHelpers "github.com/OffchainLabs/prysm/v7/validator/helpers"
 	"github.com/OffchainLabs/prysm/v7/validator/keymanager"
 	"github.com/OffchainLabs/prysm/v7/validator/keymanager/local"
 	remoteweb3signer "github.com/OffchainLabs/prysm/v7/validator/keymanager/remote-web3signer"
@@ -2792,18 +2795,27 @@ func TestValidator_Host(t *testing.T) {
 }
 
 func TestValidator_ChangeHost(t *testing.T) {
+	// Enable REST API mode for this test since changeHost only calls SwitchHost in REST API mode
+	resetCfg := features.InitWithReset(&features.Flags{EnableBeaconRESTApi: true})
+	defer resetCfg()
+
 	ctrl := gomock.NewController(t)
 	defer ctrl.Finish()
 
+	hosts := []string{"http://localhost:8080", "http://localhost:8081"}
+	restProvider := &rest.MockRestProvider{MockHosts: hosts}
+	conn, err := validatorHelpers.NewNodeConnection(validatorHelpers.WithRestProvider(restProvider))
+	require.NoError(t, err)
+
 	client := validatormock.NewMockValidatorClient(ctrl)
 	v := validator{
 		validatorClient:  client,
-		beaconNodeHosts:  []string{"http://localhost:8080", "http://localhost:8081"},
+		conn:             conn,
 		currentHostIndex: 0,
 	}
 
-	client.EXPECT().SetHost(v.beaconNodeHosts[1])
-	client.EXPECT().SetHost(v.beaconNodeHosts[0])
+	client.EXPECT().SwitchHost(hosts[1])
+	client.EXPECT().SwitchHost(hosts[0])
 	v.changeHost()
 	assert.Equal(t, uint64(1), v.currentHostIndex)
 	v.changeHost()
@@ -2838,12 +2850,16 @@ func TestUpdateValidatorStatusCache(t *testing.T) {
 		gomock.Any(),
 		gomock.Any()).Return(mockResponse, nil)
 
+	mockProvider := &grpcutil.MockGrpcProvider{MockHosts: []string{"localhost:4000", "localhost:4001"}}
+	conn, err := validatorHelpers.NewNodeConnection(validatorHelpers.WithGRPCProvider(mockProvider))
+	require.NoError(t, err)
+
 	v := &validator{
 		validatorClient:  client,
-		beaconNodeHosts:  []string{"http://localhost:8080", "http://localhost:8081"},
+		conn:             conn,
 		currentHostIndex: 0,
 		pubkeyToStatus: map[[fieldparams.BLSPubkeyLength]byte]*validatorStatus{
-			[fieldparams.BLSPubkeyLength]byte{0x03}: &validatorStatus{ // add non existent key and status to cache, should be fully removed on update
+			[fieldparams.BLSPubkeyLength]byte{0x03}: { // add non existent key and status to cache, should be fully removed on update
 				publicKey: []byte{0x03},
 				status: &ethpb.ValidatorStatusResponse{
 					Status: ethpb.ValidatorStatus_ACTIVE,
@@ -2853,7 +2869,7 @@ func TestUpdateValidatorStatusCache(t *testing.T) {
 		},
 	}
 
-	err := v.updateValidatorStatusCache(ctx, pubkeys)
+	err = v.updateValidatorStatusCache(ctx, pubkeys)
 	assert.NoError(t, err)
 
 	// make sure the nonexistent key is fully removed

validator/helpers/BUILD.bazel

@@ -10,6 +10,8 @@ go_library(
     importpath = "github.com/OffchainLabs/prysm/v7/validator/helpers",
     visibility = ["//visibility:public"],
     deps = [
+        "//api/grpc:go_default_library",
+        "//api/rest:go_default_library",
         "//config/fieldparams:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//validator/db/iface:go_default_library",
@@ -24,18 +26,23 @@ go_test(
     srcs = [
         "converts_test.go",
         "metadata_test.go",
+        "node_connection_test.go",
     ],
     embed = [":go_default_library"],
     deps = [
+        "//api/grpc:go_default_library",
+        "//api/rest:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/proposer:go_default_library",
         "//consensus-types/interfaces:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
+        "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
         "//validator/db/common:go_default_library",
         "//validator/db/iface:go_default_library",
         "//validator/slashing-protection-history/format:go_default_library",
         "@com_github_prometheus_client_golang//prometheus:go_default_library",
+        "@org_golang_google_grpc//:go_default_library",
     ],
 )

validator/helpers/node_connection.go

@@ -1,78 +1,120 @@
 package helpers
 
 import (
-	"time"
+	"context"
 
+	grpcutil "github.com/OffchainLabs/prysm/v7/api/grpc"
+	"github.com/OffchainLabs/prysm/v7/api/rest"
+	"github.com/pkg/errors"
 	"google.golang.org/grpc"
 )
 
-// Use an interface with a private dummy function to force all other packages to call NewNodeConnection
+// NodeConnection provides access to both gRPC and REST API connections to a beacon node.
 type NodeConnection interface {
+	// GetGrpcClientConn returns the current gRPC client connection.
+	// Returns nil if no gRPC provider is configured.
 	GetGrpcClientConn() *grpc.ClientConn
-	GetBeaconApiUrl() string
-	GetBeaconApiHeaders() map[string][]string
-	setBeaconApiHeaders(map[string][]string)
-	GetBeaconApiTimeout() time.Duration
-	setBeaconApiTimeout(time.Duration)
-	dummy()
+	// GetGrpcConnectionProvider returns the gRPC connection provider.
+	GetGrpcConnectionProvider() grpcutil.GrpcConnectionProvider
+	// GetRestConnectionProvider returns the REST connection provider.
+	GetRestConnectionProvider() rest.RestConnectionProvider
+	// GetRestHandler returns the REST handler for making API requests.
+	// Returns nil if no REST provider is configured.
+	GetRestHandler() rest.RestHandler
 }
 
 type nodeConnection struct {
-	grpcClientConn   *grpc.ClientConn
-	beaconApiUrl     string
-	beaconApiHeaders map[string][]string
-	beaconApiTimeout time.Duration
-}
-
-// NodeConnectionOption is a functional option for configuring the node connection.
-type NodeConnectionOption func(nc NodeConnection)
-
-// WithBeaconApiHeaders sets the HTTP headers that should be sent to the server along with each request.
-func WithBeaconApiHeaders(headers map[string][]string) NodeConnectionOption {
-	return func(nc NodeConnection) {
-		nc.setBeaconApiHeaders(headers)
-	}
-}
-
-// WithBeaconApiTimeout sets the HTTP request timeout.
-func WithBeaconApiTimeout(timeout time.Duration) NodeConnectionOption {
-	return func(nc NodeConnection) {
-		nc.setBeaconApiTimeout(timeout)
-	}
+	grpcConnectionProvider grpcutil.GrpcConnectionProvider
+	restConnectionProvider rest.RestConnectionProvider
 }
 
 func (c *nodeConnection) GetGrpcClientConn() *grpc.ClientConn {
-	return c.grpcClientConn
-}
-
-func (c *nodeConnection) GetBeaconApiUrl() string {
-	return c.beaconApiUrl
-}
-
-func (c *nodeConnection) GetBeaconApiHeaders() map[string][]string {
-	return c.beaconApiHeaders
-}
-
-func (c *nodeConnection) setBeaconApiHeaders(headers map[string][]string) {
-	c.beaconApiHeaders = headers
-}
-
-func (c *nodeConnection) GetBeaconApiTimeout() time.Duration {
-	return c.beaconApiTimeout
-}
-
-func (c *nodeConnection) setBeaconApiTimeout(timeout time.Duration) {
-	c.beaconApiTimeout = timeout
-}
-
-func (*nodeConnection) dummy() {}
-
-func NewNodeConnection(grpcConn *grpc.ClientConn, beaconApiUrl string, opts ...NodeConnectionOption) NodeConnection {
-	conn := &nodeConnection{}
-	conn.grpcClientConn = grpcConn
-	conn.beaconApiUrl = beaconApiUrl
-	for _, opt := range opts {
-		opt(conn)
+	if c.grpcConnectionProvider == nil {
+		return nil
 	}
-	return conn
+	return c.grpcConnectionProvider.CurrentConn()
+}
+
+func (c *nodeConnection) GetGrpcConnectionProvider() grpcutil.GrpcConnectionProvider {
+	return c.grpcConnectionProvider
+}
+
+func (c *nodeConnection) GetRestConnectionProvider() rest.RestConnectionProvider {
+	return c.restConnectionProvider
+}
+
+func (c *nodeConnection) GetRestHandler() rest.RestHandler {
+	if c.restConnectionProvider == nil {
+		return nil
+	}
+	return c.restConnectionProvider.RestHandler()
+}
+
+// NodeConnectionOption is a functional option for configuring a NodeConnection.
+type NodeConnectionOption func(*nodeConnection) error
+
+// WithGRPC configures a gRPC connection provider for the NodeConnection.
+// If endpoint is empty, this option is a no-op.
+func WithGRPC(ctx context.Context, endpoint string, dialOpts []grpc.DialOption) NodeConnectionOption {
+	return func(c *nodeConnection) error {
+		if endpoint == "" {
+			return nil
+		}
+		provider, err := grpcutil.NewGrpcConnectionProvider(ctx, endpoint, dialOpts)
+		if err != nil {
+			return errors.Wrap(err, "failed to create gRPC connection provider")
+		}
+		c.grpcConnectionProvider = provider
+		return nil
+	}
+}
+
+// WithREST configures a REST connection provider for the NodeConnection.
+// If endpoint is empty, this option is a no-op.
+func WithREST(endpoint string, opts ...rest.RestConnectionProviderOption) NodeConnectionOption {
+	return func(c *nodeConnection) error {
+		if endpoint == "" {
+			return nil
+		}
+		provider, err := rest.NewRestConnectionProvider(endpoint, opts...)
+		if err != nil {
+			return errors.Wrap(err, "failed to create REST connection provider")
+		}
+		c.restConnectionProvider = provider
+		return nil
+	}
+}
+
+// WithGRPCProvider sets a pre-built gRPC connection provider.
+func WithGRPCProvider(provider grpcutil.GrpcConnectionProvider) NodeConnectionOption {
+	return func(c *nodeConnection) error {
+		c.grpcConnectionProvider = provider
+		return nil
+	}
+}
+
+// WithRestProvider sets a pre-built REST connection provider.
+func WithRestProvider(provider rest.RestConnectionProvider) NodeConnectionOption {
+	return func(c *nodeConnection) error {
+		c.restConnectionProvider = provider
+		return nil
+	}
+}
+
+// NewNodeConnection creates a new NodeConnection with the given options.
+// At least one provider (gRPC or REST) must be configured via options.
+// Returns an error if no providers are configured.
+func NewNodeConnection(opts ...NodeConnectionOption) (NodeConnection, error) {
+	c := &nodeConnection{}
+	for _, opt := range opts {
+		if err := opt(c); err != nil {
+			return nil, err
+		}
+	}
+
+	if c.grpcConnectionProvider == nil && c.restConnectionProvider == nil {
+		return nil, errors.New("at least one beacon node endpoint must be provided (--beacon-rpc-provider or --beacon-rest-api-provider)")
+	}
+
+	return c, nil
 }

validator/helpers/node_connection_test.go

@@ -0,0 +1,101 @@
+package helpers
+
+import (
+	"context"
+	"testing"
+
+	grpcutil "github.com/OffchainLabs/prysm/v7/api/grpc"
+	"github.com/OffchainLabs/prysm/v7/api/rest"
+	"github.com/OffchainLabs/prysm/v7/testing/assert"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+	"google.golang.org/grpc"
+)
+
+func TestNewNodeConnection(t *testing.T) {
+	t.Run("with both providers", func(t *testing.T) {
+		grpcProvider := &grpcutil.MockGrpcProvider{MockHosts: []string{"localhost:4000"}}
+		restProvider := &rest.MockRestProvider{MockHosts: []string{"http://localhost:3500"}}
+		conn, err := NewNodeConnection(
+			WithGRPCProvider(grpcProvider),
+			WithRestProvider(restProvider),
+		)
+		require.NoError(t, err)
+
+		assert.Equal(t, grpcProvider, conn.GetGrpcConnectionProvider())
+		assert.Equal(t, restProvider, conn.GetRestConnectionProvider())
+	})
+
+	t.Run("with only rest provider", func(t *testing.T) {
+		restProvider := &rest.MockRestProvider{MockHosts: []string{"http://localhost:3500"}}
+		conn, err := NewNodeConnection(WithRestProvider(restProvider))
+		require.NoError(t, err)
+
+		assert.Equal(t, (grpcutil.GrpcConnectionProvider)(nil), conn.GetGrpcConnectionProvider())
+		assert.Equal(t, (*grpc.ClientConn)(nil), conn.GetGrpcClientConn())
+		assert.Equal(t, restProvider, conn.GetRestConnectionProvider())
+	})
+
+	t.Run("with only grpc provider", func(t *testing.T) {
+		grpcProvider := &grpcutil.MockGrpcProvider{MockHosts: []string{"localhost:4000"}}
+		conn, err := NewNodeConnection(WithGRPCProvider(grpcProvider))
+		require.NoError(t, err)
+
+		assert.Equal(t, grpcProvider, conn.GetGrpcConnectionProvider())
+		assert.Equal(t, (rest.RestConnectionProvider)(nil), conn.GetRestConnectionProvider())
+		assert.Equal(t, (rest.RestHandler)(nil), conn.GetRestHandler())
+	})
+
+	t.Run("with no providers returns error", func(t *testing.T) {
+		conn, err := NewNodeConnection()
+		require.ErrorContains(t, "at least one beacon node endpoint must be provided", err)
+		assert.Equal(t, (NodeConnection)(nil), conn)
+	})
+
+	t.Run("with empty endpoints is no-op", func(t *testing.T) {
+		// Empty endpoints should be skipped, resulting in no providers
+		conn, err := NewNodeConnection(
+			WithGRPC(context.Background(), "", nil),
+			WithREST(""),
+		)
+		require.ErrorContains(t, "at least one beacon node endpoint must be provided", err)
+		assert.Equal(t, (NodeConnection)(nil), conn)
+	})
+}
+
+func TestNodeConnection_GetGrpcClientConn(t *testing.T) {
+	t.Run("delegates to provider", func(t *testing.T) {
+		// We can't easily create a real grpc.ClientConn in tests,
+		// but we can verify the delegation works with nil
+		grpcProvider := &grpcutil.MockGrpcProvider{MockConn: nil, MockHosts: []string{"localhost:4000"}}
+		conn, err := NewNodeConnection(WithGRPCProvider(grpcProvider))
+		require.NoError(t, err)
+
+		// Should delegate to provider.CurrentConn()
+		assert.Equal(t, grpcProvider.CurrentConn(), conn.GetGrpcClientConn())
+	})
+
+	t.Run("returns nil when provider is nil", func(t *testing.T) {
+		restProvider := &rest.MockRestProvider{MockHosts: []string{"http://localhost:3500"}}
+		conn, err := NewNodeConnection(WithRestProvider(restProvider))
+		require.NoError(t, err)
+		assert.Equal(t, (*grpc.ClientConn)(nil), conn.GetGrpcClientConn())
+	})
+}
+
+func TestNodeConnection_GetRestHandler(t *testing.T) {
+	t.Run("delegates to provider", func(t *testing.T) {
+		mockHandler := &rest.MockRestHandler{}
+		restProvider := &rest.MockRestProvider{MockHandler: mockHandler, MockHosts: []string{"http://localhost:3500"}}
+		conn, err := NewNodeConnection(WithRestProvider(restProvider))
+		require.NoError(t, err)
+
+		assert.Equal(t, mockHandler, conn.GetRestHandler())
+	})
+
+	t.Run("returns nil when provider is nil", func(t *testing.T) {
+		grpcProvider := &grpcutil.MockGrpcProvider{MockHosts: []string{"localhost:4000"}}
+		conn, err := NewNodeConnection(WithGRPCProvider(grpcProvider))
+		require.NoError(t, err)
+		assert.Equal(t, (rest.RestHandler)(nil), conn.GetRestHandler())
+	})
+}

validator/node/node_test.go

@@ -41,6 +41,8 @@ func TestNode_Builds(t *testing.T) {
 	set.String("wallet-password-file", passwordFile, "path to wallet password")
 	set.String("keymanager-kind", "imported", "keymanager kind")
 	set.String("verbosity", "debug", "log verbosity")
+	set.String("beacon-rpc-provider", "localhost:4000", "beacon node RPC endpoint")
+	set.String("beacon-rest-api-provider", "http://localhost:3500", "beacon node REST API endpoint")
 	require.NoError(t, set.Set(flags.WalletPasswordFileFlag.Name, passwordFile))
 	ctx := cli.NewContext(&app, set, nil)
 	opts := []accounts.Option{

validator/rpc/BUILD.bazel

@@ -23,9 +23,9 @@ go_library(
     ],
     deps = [
         "//api:go_default_library",
-        "//api/client:go_default_library",
         "//api/grpc:go_default_library",
         "//api/pagination:go_default_library",
+        "//api/rest:go_default_library",
         "//api/server:go_default_library",
         "//api/server/httprest:go_default_library",
         "//api/server/middleware:go_default_library",
@@ -55,7 +55,6 @@ go_library(
         "//validator/accounts/petnames:go_default_library",
         "//validator/accounts/wallet:go_default_library",
         "//validator/client:go_default_library",
-        "//validator/client/beacon-api:go_default_library",
         "//validator/client/beacon-chain-client-factory:go_default_library",
         "//validator/client/iface:go_default_library",
         "//validator/client/node-client-factory:go_default_library",
@@ -79,7 +78,6 @@ go_library(
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
         "@com_github_wealdtech_go_eth2_wallet_encryptor_keystorev4//:go_default_library",
-        "@io_opentelemetry_go_contrib_instrumentation_net_http_otelhttp//:go_default_library",
         "@org_golang_google_grpc//:go_default_library",
         "@org_golang_google_grpc//codes:go_default_library",
         "@org_golang_google_grpc//metadata:go_default_library",
@@ -106,6 +104,7 @@ go_test(
     embed = [":go_default_library"],
     deps = [
         "//api:go_default_library",
+        "//api/grpc:go_default_library",
         "//async/event:go_default_library",
         "//cmd/validator/flags:go_default_library",
         "//config/features:go_default_library",

validator/rpc/beacon.go

@@ -1,13 +1,10 @@
 package rpc
 
 import (
-	"net/http"
-
-	api "github.com/OffchainLabs/prysm/v7/api/client"
 	grpcutil "github.com/OffchainLabs/prysm/v7/api/grpc"
+	"github.com/OffchainLabs/prysm/v7/api/rest"
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v7/validator/client"
-	beaconApi "github.com/OffchainLabs/prysm/v7/validator/client/beacon-api"
 	beaconChainClientFactory "github.com/OffchainLabs/prysm/v7/validator/client/beacon-chain-client-factory"
 	nodeClientFactory "github.com/OffchainLabs/prysm/v7/validator/client/node-client-factory"
 	validatorClientFactory "github.com/OffchainLabs/prysm/v7/validator/client/validator-client-factory"
@@ -17,7 +14,6 @@ import (
 	grpcopentracing "github.com/grpc-ecosystem/go-grpc-middleware/tracing/opentracing"
 	grpcprometheus "github.com/grpc-ecosystem/go-grpc-prometheus"
 	"github.com/pkg/errors"
-	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"google.golang.org/grpc"
 )
 
@@ -41,30 +37,26 @@ func (s *Server) registerBeaconClient() error {
 
 	s.ctx = grpcutil.AppendHeaders(s.ctx, s.grpcHeaders)
 
-	grpcConn, err := grpc.DialContext(s.ctx, s.beaconNodeEndpoint, dialOpts...)
+	conn, err := validatorHelpers.NewNodeConnection(
+		validatorHelpers.WithGRPC(s.ctx, s.beaconNodeEndpoint, dialOpts),
+		validatorHelpers.WithREST(s.beaconApiEndpoint,
+			rest.WithHttpHeaders(s.beaconApiHeaders),
+			rest.WithHttpTimeout(s.beaconApiTimeout),
+			rest.WithTracing(),
+		),
+	)
 	if err != nil {
-		return errors.Wrapf(err, "could not dial endpoint: %s", s.beaconNodeEndpoint)
+		return err
 	}
-	if s.beaconNodeCert != "" {
+	if s.beaconNodeCert != "" && s.beaconNodeEndpoint != "" {
 		log.Info("Established secure gRPC connection")
 	}
-	s.healthClient = ethpb.NewHealthClient(grpcConn)
+	if grpcConn := conn.GetGrpcClientConn(); grpcConn != nil {
+		s.healthClient = ethpb.NewHealthClient(grpcConn)
+	}
 
-	conn := validatorHelpers.NewNodeConnection(
-		grpcConn,
-		s.beaconApiEndpoint,
-		validatorHelpers.WithBeaconApiHeaders(s.beaconApiHeaders),
-		validatorHelpers.WithBeaconApiTimeout(s.beaconApiTimeout),
-	)
-
-	headersTransport := api.NewCustomHeadersTransport(http.DefaultTransport, conn.GetBeaconApiHeaders())
-	restHandler := beaconApi.NewBeaconApiRestHandler(
-		http.Client{Timeout: s.beaconApiTimeout, Transport: otelhttp.NewTransport(headersTransport)},
-		s.beaconApiEndpoint,
-	)
-
-	s.chainClient = beaconChainClientFactory.NewChainClient(conn, restHandler)
-	s.nodeClient = nodeClientFactory.NewNodeClient(conn, restHandler)
-	s.beaconNodeValidatorClient = validatorClientFactory.NewValidatorClient(conn, restHandler)
+	s.chainClient = beaconChainClientFactory.NewChainClient(conn)
+	s.nodeClient = nodeClientFactory.NewNodeClient(conn)
+	s.beaconNodeValidatorClient = validatorClientFactory.NewValidatorClient(conn)
 	return nil
 }

validator/rpc/beacon_test.go

@@ -3,19 +3,17 @@ package rpc
 import (
 	"testing"
 
+	grpcutil "github.com/OffchainLabs/prysm/v7/api/grpc"
 	"github.com/OffchainLabs/prysm/v7/testing/assert"
 	"github.com/OffchainLabs/prysm/v7/testing/require"
 	"google.golang.org/grpc/metadata"
 )
 
 func TestGrpcHeaders(t *testing.T) {
-	s := &Server{
-		ctx:         t.Context(),
-		grpcHeaders: []string{"first=value1", "second=value2"},
-	}
-	err := s.registerBeaconClient()
-	require.NoError(t, err)
-	md, _ := metadata.FromOutgoingContext(s.ctx)
+	ctx := t.Context()
+	grpcHeaders := []string{"first=value1", "second=value2"}
+	ctx = grpcutil.AppendHeaders(ctx, grpcHeaders)
+	md, _ := metadata.FromOutgoingContext(ctx)
 	require.Equal(t, 2, md.Len(), "MetadataV0 contains wrong number of values")
 	assert.Equal(t, "value1", md.Get("first")[0])
 	assert.Equal(t, "value2", md.Get("second")[0])

validator/rpc/handler_wallet_test.go

@@ -22,6 +22,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/validator/client"
 	"github.com/OffchainLabs/prysm/v7/validator/client/testutil"
 	"github.com/OffchainLabs/prysm/v7/validator/keymanager"
+	validatorTesting "github.com/OffchainLabs/prysm/v7/validator/testing"
 	"github.com/google/uuid"
 	"github.com/tyler-smith/go-bip39"
 	keystorev4 "github.com/wealdtech/go-eth2-wallet-encryptor-keystorev4"
@@ -46,6 +47,7 @@ func TestServer_CreateWallet_Local(t *testing.T) {
 	km, err := w.InitializeKeymanager(ctx, iface.InitKeymanagerConfig{ListenForChanges: false})
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   validatorTesting.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,
@@ -443,6 +445,7 @@ func TestServer_WalletConfig(t *testing.T) {
 	require.NoError(t, err)
 	s.wallet = w
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   validatorTesting.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,

validator/rpc/handlers_accounts_test.go

@@ -53,6 +53,7 @@ func TestServer_ListAccounts(t *testing.T) {
 	km, err := w.InitializeKeymanager(ctx, iface.InitKeymanagerConfig{ListenForChanges: false})
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   constant.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,
@@ -158,6 +159,7 @@ func TestServer_BackupAccounts(t *testing.T) {
 	km, err := w.InitializeKeymanager(ctx, iface.InitKeymanagerConfig{ListenForChanges: false})
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   constant.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,
@@ -282,6 +284,7 @@ func TestServer_VoluntaryExit(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   constant.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,

validator/rpc/handlers_keymanager_test.go

@@ -52,6 +52,7 @@ func TestServer_ListKeystores(t *testing.T) {
 	t.Run("wallet not ready", func(t *testing.T) {
 		m := &testutil.FakeValidator{}
 		vs, err := client.NewValidatorService(ctx, &client.Config{
+			Conn:      mocks.MockNodeConnection(),
 			Validator: m,
 		})
 		require.NoError(t, err)
@@ -81,6 +82,7 @@ func TestServer_ListKeystores(t *testing.T) {
 	km, err := w.InitializeKeymanager(ctx, iface.InitKeymanagerConfig{ListenForChanges: false})
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   mocks.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,
@@ -147,6 +149,7 @@ func TestServer_ImportKeystores(t *testing.T) {
 	km, err := w.InitializeKeymanager(ctx, iface.InitKeymanagerConfig{ListenForChanges: false})
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   mocks.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,
@@ -368,6 +371,7 @@ func TestServer_ImportKeystores_WrongKeymanagerKind(t *testing.T) {
 	}})
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   mocks.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,
@@ -652,6 +656,7 @@ func TestServer_DeleteKeystores_WrongKeymanagerKind(t *testing.T) {
 		}})
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   mocks.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,
@@ -695,6 +700,7 @@ func setupServerWithWallet(t testing.TB) *Server {
 	km, err := w.InitializeKeymanager(ctx, iface.InitKeymanagerConfig{ListenForChanges: false})
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   mocks.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,
@@ -730,6 +736,7 @@ func TestServer_SetVoluntaryExit(t *testing.T) {
 
 	m := &testutil.FakeValidator{Km: km}
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:      mocks.MockNodeConnection(),
 		Validator: m,
 	})
 	require.NoError(t, err)
@@ -953,6 +960,7 @@ func TestServer_GetGasLimit(t *testing.T) {
 			err := m.SetProposerSettings(ctx, tt.args)
 			require.NoError(t, err)
 			vs, err := client.NewValidatorService(ctx, &client.Config{
+				Conn:      mocks.MockNodeConnection(),
 				Validator: m,
 			})
 			require.NoError(t, err)
@@ -1111,6 +1119,7 @@ func TestServer_SetGasLimit(t *testing.T) {
 				require.NoError(t, err)
 				validatorDB := dbtest.SetupDB(t, t.TempDir(), [][fieldparams.BLSPubkeyLength]byte{}, isSlashingProtectionMinimal)
 				vs, err := client.NewValidatorService(ctx, &client.Config{
+					Conn:      mocks.MockNodeConnection(),
 					Validator: m,
 					DB:        validatorDB,
 				})
@@ -1300,6 +1309,7 @@ func TestServer_DeleteGasLimit(t *testing.T) {
 				require.NoError(t, err)
 				validatorDB := dbtest.SetupDB(t, t.TempDir(), [][fieldparams.BLSPubkeyLength]byte{}, isSlashingProtectionMinimal)
 				vs, err := client.NewValidatorService(ctx, &client.Config{
+					Conn:      mocks.MockNodeConnection(),
 					Validator: m,
 					DB:        validatorDB,
 				})
@@ -1348,6 +1358,7 @@ func TestServer_ListRemoteKeys(t *testing.T) {
 	km, err := w.InitializeKeymanager(ctx, iface.InitKeymanagerConfig{ListenForChanges: false, Web3SignerConfig: config})
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   mocks.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,
@@ -1404,6 +1415,7 @@ func TestServer_ImportRemoteKeys(t *testing.T) {
 	km, err := w.InitializeKeymanager(ctx, iface.InitKeymanagerConfig{ListenForChanges: false, Web3SignerConfig: config})
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   mocks.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,
@@ -1466,6 +1478,7 @@ func TestServer_DeleteRemoteKeys(t *testing.T) {
 	km, err := w.InitializeKeymanager(ctx, iface.InitKeymanagerConfig{ListenForChanges: false, Web3SignerConfig: config})
 	require.NoError(t, err)
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:   mocks.MockNodeConnection(),
 		Wallet: w,
 		Validator: &testutil.FakeValidator{
 			Km: km,
@@ -1567,6 +1580,7 @@ func TestServer_ListFeeRecipientByPubkey(t *testing.T) {
 			require.NoError(t, err)
 
 			vs, err := client.NewValidatorService(ctx, &client.Config{
+				Conn:      mocks.MockNodeConnection(),
 				Validator: m,
 			})
 			require.NoError(t, err)
@@ -1591,6 +1605,7 @@ func TestServer_ListFeeRecipientByPubKey_NoFeeRecipientSet(t *testing.T) {
 	ctx := t.Context()
 
 	vs, err := client.NewValidatorService(ctx, &client.Config{
+		Conn:      mocks.MockNodeConnection(),
 		Validator: &testutil.FakeValidator{},
 	})
 	require.NoError(t, err)
@@ -1780,6 +1795,7 @@ func TestServer_FeeRecipientByPubkey(t *testing.T) {
 
 				// save a default here
 				vs, err := client.NewValidatorService(ctx, &client.Config{
+					Conn:      mocks.MockNodeConnection(),
 					Validator: m,
 					DB:        validatorDB,
 				})
@@ -1890,6 +1906,7 @@ func TestServer_DeleteFeeRecipientByPubkey(t *testing.T) {
 				require.NoError(t, err)
 				validatorDB := dbtest.SetupDB(t, t.TempDir(), [][fieldparams.BLSPubkeyLength]byte{}, isSlashingProtectionMinimal)
 				vs, err := client.NewValidatorService(ctx, &client.Config{
+					Conn:      mocks.MockNodeConnection(),
 					Validator: m,
 					DB:        validatorDB,
 				})
@@ -1940,6 +1957,7 @@ func TestServer_Graffiti(t *testing.T) {
 	graffiti := "graffiti"
 	m := &testutil.FakeValidator{}
 	vs, err := client.NewValidatorService(t.Context(), &client.Config{
+		Conn:      mocks.MockNodeConnection(),
 		Validator: m,
 	})
 	require.NoError(t, err)

validator/testing/BUILD.bazel

@@ -5,6 +5,7 @@ go_library(
     testonly = True,
     srcs = [
         "constants.go",
+        "mock_node_connection.go",
         "mock_protector.go",
         "protection_history.go",
     ],
@@ -14,6 +15,7 @@ go_library(
         "//validator:__subpackages__",
     ],
     deps = [
+        "//api/grpc:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/primitives:go_default_library",
@@ -22,6 +24,7 @@ go_library(
         "//encoding/bytesutil:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//validator/db/common:go_default_library",
+        "//validator/helpers:go_default_library",
         "//validator/slashing-protection-history/format:go_default_library",
     ],
 )

validator/testing/mock_node_connection.go

@@ -0,0 +1,16 @@
+package testing
+
+import (
+	grpcutil "github.com/OffchainLabs/prysm/v7/api/grpc"
+	"github.com/OffchainLabs/prysm/v7/validator/helpers"
+)
+
+// MockNodeConnection creates a minimal NodeConnection for testing.
+func MockNodeConnection() helpers.NodeConnection {
+	conn, _ := helpers.NewNodeConnection(
+		helpers.WithGRPCProvider(&grpcutil.MockGrpcProvider{
+			MockHosts: []string{"mock:4000"},
+		}),
+	)
+	return conn
+}