diff --git a/packages/beacon-node/test/e2e/api/impl/lightclient/endpoint.test.ts b/packages/beacon-node/test/e2e/api/impl/lightclient/endpoint.test.ts
index 81154005af68..c746746741cf 100644
--- a/packages/beacon-node/test/e2e/api/impl/lightclient/endpoint.test.ts
+++ b/packages/beacon-node/test/e2e/api/impl/lightclient/endpoint.test.ts
@@ -122,7 +122,7 @@ describe("lightclient api", function () {
     const committeeRes = await lightclient.getLightClientCommitteeRoot({startPeriod: 0, count: 1});
     committeeRes.assertOk();
     const client = getClient({baseUrl: `http://127.0.0.1:${restPort}`}, {config}).beacon;
-    const validators = (await client.getStateValidators({stateId: "head"})).value();
+    const validators = (await client.postStateValidators({stateId: "head"})).value();
     const pubkeys = validators.map((v) => v.validator.pubkey);
     expect(pubkeys.length).toBe(validatorCount);
     // only 2 validators spreading to 512 committee slots
diff --git a/packages/cli/src/cmds/validator/blsToExecutionChange.ts b/packages/cli/src/cmds/validator/blsToExecutionChange.ts
index dc55647fda80..7fbdbb029bf5 100644
--- a/packages/cli/src/cmds/validator/blsToExecutionChange.ts
+++ b/packages/cli/src/cmds/validator/blsToExecutionChange.ts
@@ -60,7 +60,7 @@ like to choose for BLS To Execution Change.",
     const {genesisValidatorsRoot} = (await client.beacon.getGenesis()).value();
     const config = createBeaconConfig(chainForkConfig, genesisValidatorsRoot);
 
-    const validators = (await client.beacon.getStateValidators({stateId: "head", validatorIds: [publicKey]})).value();
+    const validators = (await client.beacon.postStateValidators({stateId: "head", validatorIds: [publicKey]})).value();
     const validator = validators[0];
     if (validator === undefined) {
       throw new Error(`Validator pubkey ${publicKey} not found in state`);
diff --git a/packages/cli/src/cmds/validator/voluntaryExit.ts b/packages/cli/src/cmds/validator/voluntaryExit.ts
index a399a763662d..02f1591b59ed 100644
--- a/packages/cli/src/cmds/validator/voluntaryExit.ts
+++ b/packages/cli/src/cmds/validator/voluntaryExit.ts
@@ -207,7 +207,7 @@ function selectSignersToExit(args: VoluntaryExitArgs, signers: Signer[]): Signer
 async function resolveValidatorIndexes(client: ApiClient, signersToExit: SignerPubkey[]) {
   const pubkeys = signersToExit.map(({pubkey}) => pubkey);
 
-  const validators = (await client.beacon.getStateValidators({stateId: "head", validatorIds: pubkeys})).value();
+  const validators = (await client.beacon.postStateValidators({stateId: "head", validatorIds: pubkeys})).value();
 
   const dataByPubkey = new Map(validators.map((item) => [toPubkeyHex(item.validator.pubkey), item]));
 
diff --git a/packages/cli/test/sim/endpoints.test.ts b/packages/cli/test/sim/endpoints.test.ts
index 07cd5fec0cc4..a42b9568f9a3 100644
--- a/packages/cli/test/sim/endpoints.test.ts
+++ b/packages/cli/test/sim/endpoints.test.ts
@@ -40,7 +40,7 @@ await env.start({runTimeoutMs: estimatedTimeoutMs});
 const node = env.nodes[0].beacon;
 await waitForSlot("Wait for 2 slots before checking endpoints", {env, slot: 2});
 
-const validators = (await node.api.beacon.getStateValidators({stateId: "head"})).value();
+const validators = (await node.api.beacon.postStateValidators({stateId: "head"})).value();
 
 await env.tracker.assert("should have correct validators count called without filters", async () => {
   assert.equal(validators.length, validatorCount);
@@ -55,12 +55,12 @@ await env.tracker.assert("should have correct validator index for second validat
 });
 
 await env.tracker.assert(
-  "should return correct number of filtered validators when getStateValidators called with filters",
+  "should return correct number of filtered validators when postStateValidators called with filters",
   async () => {
     const filterPubKey =
       "0xa99a76ed7796f7be22d5b7e85deeb7c5677e88e511e0b337618f8c4eb61349b4bf2d153f649f7b53359fe8b94a38e44c";
 
-    const res = await node.api.beacon.getStateValidators({stateId: "head", validatorIds: [filterPubKey]});
+    const res = await node.api.beacon.postStateValidators({stateId: "head", validatorIds: [filterPubKey]});
 
     assert.equal(res.value().length, 1);
 
@@ -71,12 +71,12 @@ await env.tracker.assert(
 );
 
 await env.tracker.assert(
-  "should return correct filtered validators when getStateValidators called with filters",
+  "should return correct filtered validators when postStateValidators called with filters",
   async () => {
     const filterPubKey =
       "0xa99a76ed7796f7be22d5b7e85deeb7c5677e88e511e0b337618f8c4eb61349b4bf2d153f649f7b53359fe8b94a38e44c";
 
-    const res = await node.api.beacon.getStateValidators({stateId: "head", validatorIds: [filterPubKey]});
+    const res = await node.api.beacon.postStateValidators({stateId: "head", validatorIds: [filterPubKey]});
 
     assert.equal(toHexString(res.value()[0].validator.pubkey), filterPubKey);
   }
diff --git a/packages/flare/src/cmds/selfSlashAttester.ts b/packages/flare/src/cmds/selfSlashAttester.ts
index a37c6c765bd3..6ccc9d80a98f 100644
--- a/packages/flare/src/cmds/selfSlashAttester.ts
+++ b/packages/flare/src/cmds/selfSlashAttester.ts
@@ -79,7 +79,7 @@ export async function selfSlashAttesterHandler(args: SelfSlashArgs): Promise<voi
 
     // Retrieve the status all all validators in range at once
     const pksHex = sks.map((sk) => sk.toPublicKey().toHex());
-    const validators = (await client.beacon.getStateValidators({stateId: "head", validatorIds: pksHex})).value();
+    const validators = (await client.beacon.postStateValidators({stateId: "head", validatorIds: pksHex})).value();
 
     // All validators in the batch will be part of the same AttesterSlashing
     const attestingIndices = validators.map((v) => v.index);
@@ -92,7 +92,7 @@ export async function selfSlashAttesterHandler(args: SelfSlashArgs): Promise<voi
       const pkHex = pksHex[i];
       const validatorPkHex = toPubkeyHex(validator.pubkey);
       if (validatorPkHex !== pkHex) {
-        throw Error(`getStateValidators did not return same validator pubkey: ${validatorPkHex} != ${pkHex}`);
+        throw Error(`Beacon node did not return same validator pubkey: ${validatorPkHex} != ${pkHex}`);
       }
 
       if (status === "active_slashed" || status === "exited_slashed") {
diff --git a/packages/flare/src/cmds/selfSlashProposer.ts b/packages/flare/src/cmds/selfSlashProposer.ts
index b79b7fdcd4b9..14a270239268 100644
--- a/packages/flare/src/cmds/selfSlashProposer.ts
+++ b/packages/flare/src/cmds/selfSlashProposer.ts
@@ -77,7 +77,7 @@ export async function selfSlashProposerHandler(args: SelfSlashArgs): Promise<voi
 
     // Retrieve the status all all validators in range at once
     const pksHex = sks.map((sk) => sk.toPublicKey().toHex());
-    const validators = (await client.beacon.getStateValidators({stateId: "head", validatorIds: pksHex})).value();
+    const validators = (await client.beacon.postStateValidators({stateId: "head", validatorIds: pksHex})).value();
 
     // Submit all ProposerSlashing for range at once
     await Promise.all(
@@ -88,7 +88,7 @@ export async function selfSlashProposerHandler(args: SelfSlashArgs): Promise<voi
         try {
           const validatorPkHex = toPubkeyHex(validator.pubkey);
           if (validatorPkHex !== pkHex) {
-            throw Error(`getStateValidators did not return same validator pubkey: ${validatorPkHex} != ${pkHex}`);
+            throw Error(`Beacon node did not return same validator pubkey: ${validatorPkHex} != ${pkHex}`);
           }
 
           if (status === "active_slashed" || status === "exited_slashed") {
diff --git a/packages/validator/src/services/indices.ts b/packages/validator/src/services/indices.ts
index ec5155322918..c3f511669bf1 100644
--- a/packages/validator/src/services/indices.ts
+++ b/packages/validator/src/services/indices.ts
@@ -5,10 +5,12 @@ import {batchItems} from "../util/index.js";
 import {Metrics} from "../metrics.js";
 
 /**
- * URLs have a limitation on size, adding an unbounded num of pubkeys will break the request.
- * For reasoning on the specific number see: https://github.com/ethereum/beacon-APIs/pull/328
+ * This is to prevent the "Request body is too large" issue for http post.
+ * Typical servers accept up to 1MB (2 ** 20 bytes) of request body, for example fastify and nginx.
+ * A hex encoded public key with "0x"-prefix has a size of 98 bytes + 2 bytes to account for commas
+ * and other JSON padding. `Math.floor(2 ** 20 / 100) == 10485`, we can send up to ~10k keys per request.
  */
-const PUBKEYS_PER_REQUEST = 64;
+const PUBKEYS_PER_REQUEST = 10_000;
 
 // To assist with readability
 type PubkeyHex = string;
@@ -108,7 +110,7 @@ export class IndicesService {
     }
 
     // Query the remote BN to resolve a pubkey to a validator index.
-    // support up to 1000 pubkeys per poll
+    // support up to 10k pubkeys per poll
     const pubkeysHexBatches = batchItems(pubkeysHexToDiscover, {batchSize: PUBKEYS_PER_REQUEST});
 
     const newIndices: number[] = [];
@@ -123,7 +125,7 @@ export class IndicesService {
   }
 
   private async fetchValidatorIndices(pubkeysHex: string[]): Promise<ValidatorIndex[]> {
-    const validators = (await this.api.beacon.getStateValidators({stateId: "head", validatorIds: pubkeysHex})).value();
+    const validators = (await this.api.beacon.postStateValidators({stateId: "head", validatorIds: pubkeysHex})).value();
 
     const newIndices = [];
 
diff --git a/packages/validator/src/validator.ts b/packages/validator/src/validator.ts
index 980e64f7eac2..6ffebff2b3bd 100644
--- a/packages/validator/src/validator.ts
+++ b/packages/validator/src/validator.ts
@@ -372,7 +372,9 @@ export class Validator {
    * Create a signed voluntary exit message for the given validator by its key.
    */
   async signVoluntaryExit(publicKey: string, exitEpoch?: number): Promise<phase0.SignedVoluntaryExit> {
-    const validators = (await this.api.beacon.getStateValidators({stateId: "head", validatorIds: [publicKey]})).value();
+    const validators = (
+      await this.api.beacon.postStateValidators({stateId: "head", validatorIds: [publicKey]})
+    ).value();
 
     const validator = validators[0];
     if (validator === undefined) {
diff --git a/packages/validator/test/unit/services/attestation.test.ts b/packages/validator/test/unit/services/attestation.test.ts
index 356503cbdd09..66b722273102 100644
--- a/packages/validator/test/unit/services/attestation.test.ts
+++ b/packages/validator/test/unit/services/attestation.test.ts
@@ -105,7 +105,7 @@ describe("AttestationService", function () {
         ];
 
         // Return empty replies to duties service
-        api.beacon.getStateValidators.mockResolvedValue(
+        api.beacon.postStateValidators.mockResolvedValue(
           mockApiResponse({data: [], meta: {executionOptimistic: false, finalized: false}})
         );
         api.validator.getAttesterDuties.mockResolvedValue(
diff --git a/packages/validator/test/unit/services/attestationDuties.test.ts b/packages/validator/test/unit/services/attestationDuties.test.ts
index 751ebcf11205..a9d50eaf42c6 100644
--- a/packages/validator/test/unit/services/attestationDuties.test.ts
+++ b/packages/validator/test/unit/services/attestationDuties.test.ts
@@ -52,7 +52,7 @@ describe("AttestationDutiesService", function () {
       index,
       validator: {...defaultValidator.validator, pubkey: pubkeys[0]},
     };
-    api.beacon.getStateValidators.mockResolvedValue(
+    api.beacon.postStateValidators.mockResolvedValue(
       mockApiResponse({data: [validatorResponse], meta: {executionOptimistic: false, finalized: false}})
     );
   });
diff --git a/packages/validator/test/unit/services/syncCommitteDuties.test.ts b/packages/validator/test/unit/services/syncCommitteDuties.test.ts
index 10bac3ab2fe9..dc43502d5b57 100644
--- a/packages/validator/test/unit/services/syncCommitteDuties.test.ts
+++ b/packages/validator/test/unit/services/syncCommitteDuties.test.ts
@@ -60,7 +60,7 @@ describe("SyncCommitteeDutiesService", function () {
       index: indices[i],
       validator: {...defaultValidator.validator, pubkey: pubkeys[i]},
     }));
-    api.beacon.getStateValidators.mockResolvedValue(
+    api.beacon.postStateValidators.mockResolvedValue(
       mockApiResponse({data: validatorResponses, meta: {executionOptimistic: false, finalized: false}})
     );
   });
diff --git a/packages/validator/test/unit/services/syncCommittee.test.ts b/packages/validator/test/unit/services/syncCommittee.test.ts
index 66e63ab72a6c..449f826c3806 100644
--- a/packages/validator/test/unit/services/syncCommittee.test.ts
+++ b/packages/validator/test/unit/services/syncCommittee.test.ts
@@ -102,7 +102,7 @@ describe("SyncCommitteeService", function () {
         ];
 
         // Return empty replies to duties service
-        api.beacon.getStateValidators.mockResolvedValue(
+        api.beacon.postStateValidators.mockResolvedValue(
           mockApiResponse({data: [], meta: {executionOptimistic: false, finalized: false}})
         );
         api.validator.getSyncCommitteeDuties.mockResolvedValue(
diff --git a/packages/validator/test/utils/apiStub.ts b/packages/validator/test/utils/apiStub.ts
index ef615af03369..4443dab5c4ac 100644
--- a/packages/validator/test/utils/apiStub.ts
+++ b/packages/validator/test/utils/apiStub.ts
@@ -16,6 +16,7 @@ export function getApiClientStub(): ApiClientStub {
   return {
     beacon: {
       getStateValidators: vi.fn(),
+      postStateValidators: vi.fn(),
       publishBlindedBlockV2: vi.fn(),
       publishBlockV2: vi.fn(),
       submitPoolSyncCommitteeSignatures: vi.fn(),