diff --git a/packages/validator/src/services/indices.ts b/packages/validator/src/services/indices.ts
index 2a6d84aad878..3ae707610101 100644
--- a/packages/validator/src/services/indices.ts
+++ b/packages/validator/src/services/indices.ts
@@ -3,6 +3,13 @@ import {ILogger} from "@chainsafe/lodestar-utils";
 import {toHexString} from "@chainsafe/ssz";
 import {Api} from "@chainsafe/lodestar-api";
 import {ValidatorStore} from "./validatorStore";
+import {batchItems} from "../util/batch";
+
+/**
+ * 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/ChainSafe/lodestar/pull/2730#issuecomment-866749083
+ */
+const PUBKEYS_PER_REQUEST = 10;
 
 // To assist with readability
 type PubkeyHex = string;
@@ -59,20 +66,19 @@ export class IndicesService {
 
     // Query the remote BN to resolve a pubkey to a validator index.
     // support up to 1000 pubkeys per poll
-    const pubkeysHex = pubkeysToPoll.map((pubkey) => toHexString(pubkey)).slice(0, MAX_PUBKEYS_PER_POLL);
-    const batches = pubkeysToBatches(pubkeysHex);
+    const pubkeysHex = pubkeysToPoll.map((pubkey) => toHexString(pubkey));
+    const pubkeysHexBatches = batchItems(pubkeysHex, {batchSize: PUBKEYS_PER_REQUEST});
 
-    const newIndicesArr = [];
-    for (const batch of batches) {
-      const validatorIndicesArr = await Promise.all(batch.map(this.getIndicesPerHttpRequest));
-      newIndicesArr.push(...validatorIndicesArr.flat());
+    const newIndices: number[] = [];
+    for (const pubkeysHexBatch of pubkeysHexBatches) {
+      const validatorIndicesArr = await this.fetchValidatorIndices(pubkeysHexBatch);
+      newIndices.push(...validatorIndicesArr);
     }
-    const newIndices = newIndicesArr.flat();
     this.logger.info("Discovered new validators", {count: newIndices.length});
     return newIndices;
   }
 
-  private getIndicesPerHttpRequest = async (pubkeysHex: string[]): Promise<ValidatorIndex[]> => {
+  private async fetchValidatorIndices(pubkeysHex: string[]): Promise<ValidatorIndex[]> {
     const validatorsState = await this.api.beacon.getStateValidators("head", {indices: pubkeysHex});
     const newIndices = [];
     for (const validatorState of validatorsState.data) {
@@ -85,41 +91,5 @@ export class IndicesService {
       }
     }
     return newIndices;
-  };
-}
-
-type Batch = string[][];
-const PUBKEYS_PER_REQUEST = 10;
-const REQUESTS_PER_BATCH = 5;
-const MAX_PUBKEYS_PER_POLL = 5 * PUBKEYS_PER_REQUEST * REQUESTS_PER_BATCH;
-
-/**
- * Divide pubkeys into batches, each batch contains at most 5 http requests,
- * each request can work on at most 40 pubkeys.
- * @param pubkeysHex
- */
-export function pubkeysToBatches(
-  pubkeysHex: string[],
-  maxPubkeysPerRequest: number = PUBKEYS_PER_REQUEST,
-  maxRequesPerBatch: number = REQUESTS_PER_BATCH
-): Batch[] {
-  if (!pubkeysHex || pubkeysHex.length === 0) {
-    return [[[]]];
-  }
-  const batches: Batch[] = [];
-
-  const pubkeysPerBatch = maxPubkeysPerRequest * maxRequesPerBatch;
-  let batch: Batch = [];
-  let pubkeysPerRequest: string[];
-  for (let i = 0; i < pubkeysHex.length; i += maxPubkeysPerRequest) {
-    if (i % pubkeysPerBatch === 0) {
-      batch = [];
-      batches.push(batch);
-    }
-    if (i % maxPubkeysPerRequest === 0) {
-      pubkeysPerRequest = pubkeysHex.slice(i, Math.min(i + maxPubkeysPerRequest, pubkeysHex.length));
-      batch.push(pubkeysPerRequest);
-    }
   }
-  return batches;
 }
diff --git a/packages/validator/src/util/batch.ts b/packages/validator/src/util/batch.ts
new file mode 100644
index 000000000000..f0cfa9c7ee9d
--- /dev/null
+++ b/packages/validator/src/util/batch.ts
@@ -0,0 +1,16 @@
+/**
+ * Divide pubkeys into batches, each batch contains at most 5 http requests,
+ * each request can work on at most 40 pubkeys.
+ */
+export function batchItems<T>(items: T[], opts: {batchSize: number; maxBatches?: number}): T[][] {
+  const batches: T[][] = [];
+  const maxBatches = opts.maxBatches ?? Math.ceil(items.length / opts.batchSize);
+
+  for (let i = 0; i < maxBatches; i++) {
+    const batch = items.slice(opts.batchSize * i, opts.batchSize * (i + 1));
+    if (batch.length === 0) break;
+    batches.push(batch);
+  }
+
+  return batches;
+}
diff --git a/packages/validator/test/unit/services/indices.test.ts b/packages/validator/test/unit/services/indices.test.ts
deleted file mode 100644
index be8346bea22d..000000000000
--- a/packages/validator/test/unit/services/indices.test.ts
+++ /dev/null
@@ -1,50 +0,0 @@
-import {expect} from "chai";
-import {pubkeysToBatches} from "../../../src/services/indices";
-
-describe("pubkeysToBatches", function () {
-  const testCases: {pubkeys: string[]; expected: string[][][]}[] = [
-    {pubkeys: [], expected: [[[]]]},
-    {pubkeys: ["1"], expected: [[["1"]]]},
-    {pubkeys: ["1", "2"], expected: [[["1", "2"]]]},
-    {pubkeys: ["1", "2", "3"], expected: [[["1", "2"], ["3"]]]},
-    {
-      pubkeys: ["1", "2", "3", "4"],
-      expected: [
-        [
-          ["1", "2"],
-          ["3", "4"],
-        ],
-      ],
-    },
-    {pubkeys: ["1", "2", "3", "4", "5"], expected: [[["1", "2"], ["3", "4"], ["5"]]]},
-    {
-      pubkeys: ["1", "2", "3", "4", "5", "6"],
-      expected: [
-        [
-          ["1", "2"],
-          ["3", "4"],
-          ["5", "6"],
-        ],
-      ],
-    },
-    // new batch
-    {
-      pubkeys: ["1", "2", "3", "4", "5", "6", "7"],
-      expected: [
-        [
-          ["1", "2"],
-          ["3", "4"],
-          ["5", "6"],
-        ],
-        [["7"]],
-      ],
-    },
-  ];
-  const maxPubkeysPerRequest = 2;
-  const maxRequestsPerBatch = 3;
-  for (const {pubkeys, expected} of testCases) {
-    it(`should work with ${pubkeys.length} pubkeys`, () => {
-      expect(pubkeysToBatches(pubkeys, maxPubkeysPerRequest, maxRequestsPerBatch)).to.be.deep.equals(expected);
-    });
-  }
-});
diff --git a/packages/validator/test/unit/utils/batch.test.ts b/packages/validator/test/unit/utils/batch.test.ts
new file mode 100644
index 000000000000..71e51dc6e82a
--- /dev/null
+++ b/packages/validator/test/unit/utils/batch.test.ts
@@ -0,0 +1,42 @@
+import {expect} from "chai";
+import {batchItems} from "../../../src/util/batch";
+
+describe("util / batch", function () {
+  const testCases: {items: string[]; expected: string[][]}[] = [
+    {items: [], expected: []},
+    {items: ["1"], expected: [["1"]]},
+    {items: ["1", "2"], expected: [["1", "2"]]},
+    {items: ["1", "2", "3"], expected: [["1", "2"], ["3"]]},
+    {
+      items: ["1", "2", "3", "4"],
+      expected: [
+        ["1", "2"],
+        ["3", "4"],
+      ],
+    },
+    {items: ["1", "2", "3", "4", "5"], expected: [["1", "2"], ["3", "4"], ["5"]]},
+    {
+      items: ["1", "2", "3", "4", "5", "6"],
+      expected: [
+        ["1", "2"],
+        ["3", "4"],
+        ["5", "6"],
+      ],
+    },
+    // Ignore item 7 since it's over the max
+    {
+      items: ["1", "2", "3", "4", "5", "6", "7"],
+      expected: [
+        ["1", "2"],
+        ["3", "4"],
+        ["5", "6"],
+      ],
+    },
+  ];
+
+  for (const {items: pubkeys, expected} of testCases) {
+    it(`Batch ${pubkeys.length} items`, () => {
+      expect(batchItems(pubkeys, {batchSize: 2, maxBatches: 3})).to.deep.equal(expected);
+    });
+  }
+});