diff --git a/packages/cli/src/controller/migrate-controller.ts b/packages/cli/src/controller/migrate-controller.ts
index 6951ecef1d..6cf8d44d8b 100644
--- a/packages/cli/src/controller/migrate-controller.ts
+++ b/packages/cli/src/controller/migrate-controller.ts
@@ -10,7 +10,7 @@ import {
   ChainTypes,
   loadSubstrateProjectManifest,
 } from '@subql/common-substrate';
-import {loadTerraProjectManifest, TerraProjectManifestVersioned} from '@subql/common-terra';
+import {loadTerraProjectManifest, TerraProjectManifestVersioned, TerraProjectNetworkV0_3_0} from '@subql/common-terra';
 import {classToPlain} from 'class-transformer';
 import {cli} from 'cli-ux';
 import inquirer from 'inquirer';
@@ -63,7 +63,9 @@ export async function prepare(
   if (project.runner.node.name === SUBSTRATE_NODE_NAME) {
     cli.action.start('Getting network genesis hash from endpoint for Chain ID');
     try {
-      genesisHash = await getGenesisHash(projectNetwork.endpoint);
+      genesisHash = await getGenesisHash(
+        typeof projectNetwork.endpoint === 'string' ? projectNetwork.endpoint : projectNetwork.endpoint[0]
+      );
     } catch (e) {
       genesisHash = null;
     }
diff --git a/packages/common-substrate/src/project/versioned/v0_0_1/model.ts b/packages/common-substrate/src/project/versioned/v0_0_1/model.ts
index d89ba49a3d..bf2c9184ee 100644
--- a/packages/common-substrate/src/project/versioned/v0_0_1/model.ts
+++ b/packages/common-substrate/src/project/versioned/v0_0_1/model.ts
@@ -25,8 +25,8 @@ import {SubstrateProjectNetworkConfig} from '../../types';
 import {ManifestV0_0_1Mapping, ProjectManifestV0_0_1, RuntimeDataSourceV0_0_1} from './types';
 
 export class ProjectNetworkV0_0_1 extends ChainTypes implements SubstrateProjectNetworkConfig {
-  @IsString()
-  endpoint: string;
+  @IsString({each: true})
+  endpoint: string[];
   @IsString()
   @IsOptional()
   dictionary?: string;
diff --git a/packages/common-substrate/src/project/versioned/v0_2_0/model.ts b/packages/common-substrate/src/project/versioned/v0_2_0/model.ts
index 73e987a95e..825e6c0386 100644
--- a/packages/common-substrate/src/project/versioned/v0_2_0/model.ts
+++ b/packages/common-substrate/src/project/versioned/v0_2_0/model.ts
@@ -34,9 +34,9 @@ export class ProjectNetworkDeploymentV0_2_0 {
 }
 
 export class ProjectNetworkV0_2_0 extends ProjectNetworkDeploymentV0_2_0 {
-  @IsString()
+  @IsString({each: true})
   @IsOptional()
-  endpoint?: string;
+  endpoint?: string | string[];
   @IsString()
   @IsOptional()
   dictionary?: string;
diff --git a/packages/common-substrate/src/project/versioned/v0_3_0/types.ts b/packages/common-substrate/src/project/versioned/v0_3_0/types.ts
index 77a1ca4095..fde977d811 100644
--- a/packages/common-substrate/src/project/versioned/v0_3_0/types.ts
+++ b/packages/common-substrate/src/project/versioned/v0_3_0/types.ts
@@ -18,7 +18,7 @@ export interface SubstrateProjectManifestV0_3_0 extends ISubstrateProjectManifes
 
   network: {
     genesisHash: string;
-    endpoint?: string;
+    endpoint?: string | string[];
     dictionary?: string;
     chaintypes?: {
       file: string;
diff --git a/packages/common-substrate/src/project/versioned/v1_0_0/model.ts b/packages/common-substrate/src/project/versioned/v1_0_0/model.ts
index 315a09e402..0936a32d60 100644
--- a/packages/common-substrate/src/project/versioned/v1_0_0/model.ts
+++ b/packages/common-substrate/src/project/versioned/v1_0_0/model.ts
@@ -74,9 +74,9 @@ export class ProjectNetworkDeploymentV1_0_0 {
 }
 
 export class ProjectNetworkV1_0_0 extends ProjectNetworkDeploymentV1_0_0 {
-  @IsString()
+  @IsString({each: true})
   @IsOptional()
-  endpoint?: string;
+  endpoint?: string | string[];
   @IsString()
   @IsOptional()
   dictionary?: string;
diff --git a/packages/common/src/project/types.ts b/packages/common/src/project/types.ts
index 00d7bb3c93..41c9d6e02b 100644
--- a/packages/common/src/project/types.ts
+++ b/packages/common/src/project/types.ts
@@ -11,7 +11,7 @@ export interface IProjectManifest<D> {
 }
 
 export interface ProjectNetworkConfig {
-  endpoint: string;
+  endpoint: string | string[];
   dictionary?: string;
   bypassBlocks?: (number | string)[];
   //genesisHash?: string;
diff --git a/packages/common/src/project/utils.ts b/packages/common/src/project/utils.ts
index 5111d2e131..c9455304a8 100644
--- a/packages/common/src/project/utils.ts
+++ b/packages/common/src/project/utils.ts
@@ -59,7 +59,7 @@ export function validateSemver(current: string, required: string): boolean {
 @ValidatorConstraint({name: 'semver', async: false})
 export class SemverVersionValidator implements ValidatorConstraintInterface {
   validate(value: string | null | undefined): boolean {
-    if (valid(value, {includePrerelease: false}) === null) {
+    if (valid(value) === null) {
       return validRange(value, {includePrerelease: false}) !== null;
     } else {
       return prerelease(value) === null;
diff --git a/packages/common/src/project/versioned/v0_2_0/types.ts b/packages/common/src/project/versioned/v0_2_0/types.ts
index e84b134d8f..0926fdd27b 100644
--- a/packages/common/src/project/versioned/v0_2_0/types.ts
+++ b/packages/common/src/project/versioned/v0_2_0/types.ts
@@ -11,7 +11,7 @@ export interface ProjectManifestV0_2_0<D extends object = BaseDataSource> {
   };
   network: {
     genesisHash: string;
-    endpoint?: string;
+    endpoint?: string | string[];
     dictionary?: string;
     chaintypes?: {
       file: string;
diff --git a/packages/common/src/project/versioned/v1_0_0/types.ts b/packages/common/src/project/versioned/v1_0_0/types.ts
index 92b8728a5c..095fb46215 100644
--- a/packages/common/src/project/versioned/v1_0_0/types.ts
+++ b/packages/common/src/project/versioned/v1_0_0/types.ts
@@ -26,7 +26,7 @@ export interface ProjectManifestV1_0_0<T extends object = TemplateBase, D extend
   templates?: T[];
   network: {
     chainId: string;
-    endpoint?: string;
+    endpoint?: string | string[];
     dictionary?: string;
     bypassBlocks?: (number | string)[];
     chaintypes?: {
diff --git a/packages/node-core/src/configure/NodeConfig.ts b/packages/node-core/src/configure/NodeConfig.ts
index f60277b373..bcf6f1f34d 100644
--- a/packages/node-core/src/configure/NodeConfig.ts
+++ b/packages/node-core/src/configure/NodeConfig.ts
@@ -22,7 +22,7 @@ export interface IConfig {
   readonly blockTime: number;
   readonly debug: boolean;
   readonly preferRange: boolean;
-  readonly networkEndpoint?: string;
+  readonly networkEndpoint?: string[];
   readonly networkDictionary?: string;
   readonly dictionaryResolver?: string;
   readonly outputFmt?: 'json';
@@ -109,8 +109,10 @@ export class NodeConfig implements IConfig {
     return this._config.batchSize;
   }
 
-  get networkEndpoint(): string | undefined {
-    return this._config.networkEndpoint;
+  get networkEndpoints(): string[] | undefined {
+    return typeof this._config.networkEndpoint === 'string'
+      ? [this._config.networkEndpoint]
+      : this._config.networkEndpoint;
   }
 
   get networkDictionary(): string | undefined {
diff --git a/packages/node-core/src/indexer/connectionPool.service.ts b/packages/node-core/src/indexer/connectionPool.service.ts
new file mode 100644
index 0000000000..d34a63366d
--- /dev/null
+++ b/packages/node-core/src/indexer/connectionPool.service.ts
@@ -0,0 +1,76 @@
+// Copyright 2020-2022 OnFinality Limited authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import {Injectable, OnApplicationShutdown} from '@nestjs/common';
+import {toNumber} from 'lodash';
+import {getLogger} from '../logger';
+
+const logger = getLogger('api');
+
+export interface ApiConnection {
+  apiConnect(): Promise<void>;
+  apiDisconnect(): Promise<void>;
+}
+
+@Injectable()
+export class ConnectionPoolService<T extends ApiConnection> implements OnApplicationShutdown {
+  private allApi: T[] = [];
+  private connectionPool: Record<number, T> = {};
+  private taskCounter = 0;
+
+  async onApplicationShutdown(): Promise<void> {
+    await Promise.all(
+      Object.keys(this.connectionPool)?.map((key) => this.connectionPool[toNumber(key)].apiDisconnect())
+    );
+  }
+
+  addToConnections(api: T): void {
+    this.allApi.push(api);
+    this.connectionPool[this.allApi.length - 1] = api;
+  }
+
+  addBatchToConnections(apis: T[]): void {
+    apis.forEach((api) => this.addToConnections(api));
+  }
+
+  async connectToApi(apiIndex: number): Promise<void> {
+    await this.allApi[apiIndex].apiConnect();
+  }
+
+  get api(): T {
+    const index = this.getNextConnectedApiIndex();
+    if (index === -1) {
+      throw new Error('No connected api');
+    }
+    return this.connectionPool[index];
+  }
+
+  getNextConnectedApiIndex(): number {
+    if (Object.keys(this.connectionPool).length === 0) {
+      return -1;
+    }
+    const nextIndex = this.taskCounter % Object.keys(this.connectionPool).length;
+    this.taskCounter++;
+    return toNumber(Object.keys(this.connectionPool)[nextIndex]);
+  }
+
+  get numConnections(): number {
+    return Object.keys(this.connectionPool).length;
+  }
+
+  async handleApiDisconnects(apiIndex: number, endpoint: string): Promise<void> {
+    logger.warn(`disconnected from ${endpoint}`);
+    delete this.connectionPool[apiIndex];
+
+    try {
+      logger.debug(`reconnecting to ${endpoint}...`);
+      await this.connectToApi(apiIndex);
+    } catch (e) {
+      logger.error(`unable to reconnect to endpoint ${endpoint}`, e);
+      return;
+    }
+
+    logger.info(`reconnected to ${endpoint}!`);
+    this.connectionPool[apiIndex] = this.allApi[apiIndex];
+  }
+}
diff --git a/packages/node-core/src/indexer/dictionary.service.test.ts b/packages/node-core/src/indexer/dictionary.service.test.ts
index 457d27e8ae..849e5a19c7 100644
--- a/packages/node-core/src/indexer/dictionary.service.test.ts
+++ b/packages/node-core/src/indexer/dictionary.service.test.ts
@@ -105,7 +105,7 @@ const HAPPY_PATH_CONDITIONS: DictionaryQueryEntry[] = [
 const nodeConfig = new NodeConfig({
   subquery: 'asdf',
   subqueryName: 'asdf',
-  networkEndpoint: 'wss://polkadot.api.onfinality.io/public-ws',
+  networkEndpoint: ['wss://polkadot.api.onfinality.io/public-ws'],
   dictionaryTimeout: 10,
 });
 
diff --git a/packages/node-core/src/indexer/index.ts b/packages/node-core/src/indexer/index.ts
index 008b63fe00..cb1a30fb18 100644
--- a/packages/node-core/src/indexer/index.ts
+++ b/packages/node-core/src/indexer/index.ts
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 export * from './benchmark.service';
+export * from './connectionPool.service';
 export * from './entities';
 export * from './PoiBlock';
 export * from './types';
@@ -12,4 +13,4 @@ export * from './mmr.service';
 export * from './worker';
 export * from './dictionary.service';
 export * from './sandbox';
-export * from './smartBatch.service';
\ No newline at end of file
+export * from './smartBatch.service';
diff --git a/packages/node-core/src/utils/object.ts b/packages/node-core/src/utils/object.ts
index 579e39dedf..127aabc10a 100644
--- a/packages/node-core/src/utils/object.ts
+++ b/packages/node-core/src/utils/object.ts
@@ -20,3 +20,14 @@ export function camelCaseObjectKey(object: Record<string, any>): object {
     {}
   );
 }
+
+export function splitArrayByRatio(arr: number[], weights: number[]): number[][] {
+  const result: number[][] = [];
+  let start = 0;
+  for (let i = 0; i < weights.length; i++) {
+    const end = Math.floor(arr.length * weights[i]) + start;
+    result.push(arr.slice(start, end));
+    start = end;
+  }
+  return result;
+}
diff --git a/packages/node/src/configure/SubqueryProject.spec.ts b/packages/node/src/configure/SubqueryProject.spec.ts
index 8f23d1fbff..87641f9e9f 100644
--- a/packages/node/src/configure/SubqueryProject.spec.ts
+++ b/packages/node/src/configure/SubqueryProject.spec.ts
@@ -36,7 +36,7 @@ describe('SubqueryProject', () => {
     it('convert local 0.2.0 manifest to project object', async () => {
       //manually pass the endpoint
       const project = await SubqueryProject.create(projectDirV0_2_0, {
-        endpoint: 'wss://rpc.polkadot.io/public-ws',
+        endpoint: ['wss://rpc.polkadot.io/public-ws'],
       });
 
       expect((project.dataSources[1] as any).processor.file).toMatch(
@@ -47,7 +47,7 @@ describe('SubqueryProject', () => {
     it('convert local 0.3.0 manifest to project object', async () => {
       //manually pass the endpoint
       const project = await SubqueryProject.create(projectDirV0_3_0, {
-        endpoint: 'wss://rpc.polkadot.io/public-ws',
+        endpoint: ['wss://rpc.polkadot.io/public-ws'],
       });
 
       expect((project.dataSources[1] as any).processor.file).toMatch(
@@ -60,7 +60,7 @@ describe('SubqueryProject', () => {
       //manually pass the endpoint
       const project = await SubqueryProject.create(
         deployment,
-        { endpoint: 'wss://rpc.polkadot.io/public-ws' },
+        { endpoint: ['wss://rpc.polkadot.io/public-ws'] },
         { ipfs: 'http://127.0.0.1:8080' },
       );
     }, 5000000);
@@ -77,7 +77,7 @@ describe('SubqueryProject', () => {
         },
       };
       const project = await SubqueryProject.create(projectDirV1_0_0, {
-        endpoint: 'wss://rpc.polkadot.io/public-ws',
+        endpoint: ['wss://rpc.polkadot.io/public-ws'],
       });
 
       expect(project.runner).toMatchObject(expectedRunner);
@@ -85,7 +85,7 @@ describe('SubqueryProject', () => {
 
     it('check processChainId', async () => {
       const project = await SubqueryProject.create(projectDirV1_0_0, {
-        endpoint: 'wss://rpc.polkadot.io/public-ws',
+        endpoint: ['wss://rpc.polkadot.io/public-ws'],
       });
       expect(project.network.chainId).toMatch(
         '0x401a1f9dca3da46f5c4091016c8a2f26dcea05865116b286f60f668207d1474b',
@@ -94,10 +94,10 @@ describe('SubqueryProject', () => {
 
     it('check loadProjectTemplates', async () => {
       const project = await SubqueryProject.create(templateProject, {
-        endpoint: 'wss://moonbeam-alpha.api.onfinality.io/public-ws',
+        endpoint: ['wss://moonbeam-alpha.api.onfinality.io/public-ws'],
       });
       const project_v1 = await SubqueryProject.create(projectDirV1_0_0, {
-        endpoint: 'wss://rpc.polkadot.io/public-ws',
+        endpoint: ['wss://rpc.polkadot.io/public-ws'],
       });
       expect(project_v1).not.toContain('template');
       expect(project.templates.length).toBe(1);
diff --git a/packages/node/src/configure/SubqueryProject.ts b/packages/node/src/configure/SubqueryProject.ts
index f6e13f67dd..70d819268b 100644
--- a/packages/node/src/configure/SubqueryProject.ts
+++ b/packages/node/src/configure/SubqueryProject.ts
@@ -108,7 +108,7 @@ export class SubqueryProject {
 
 export interface SubqueryProjectNetwork {
   chainId: string;
-  endpoint?: string;
+  endpoint?: string[];
   dictionary?: string;
   chaintypes?: FileType;
 }
@@ -137,6 +137,10 @@ async function loadProjectFromManifestBase(
 ): Promise<SubqueryProject> {
   const root = await getProjectRoot(reader);
 
+  if (typeof projectManifest.network.endpoint === 'string') {
+    projectManifest.network.endpoint = [projectManifest.network.endpoint];
+  }
+
   const network = processChainId({
     ...projectManifest.network,
     ...networkOverrides,
diff --git a/packages/node/src/configure/configure.module.ts b/packages/node/src/configure/configure.module.ts
index 2df4d75492..8a8d2da8c5 100644
--- a/packages/node/src/configure/configure.module.ts
+++ b/packages/node/src/configure/configure.module.ts
@@ -108,7 +108,7 @@ export class ConfigureModule {
         config.subquery,
         omitBy<SubstrateProjectNetworkConfig>(
           {
-            endpoint: config.networkEndpoint,
+            endpoint: config.networkEndpoints,
             dictionary: config.networkDictionary,
           },
           isNil,
@@ -170,7 +170,7 @@ export class ConfigureModule {
         argv.subquery,
         omitBy<SubstrateProjectNetworkConfig>(
           {
-            endpoint: config.networkEndpoint,
+            endpoint: config.networkEndpoints,
             dictionary: config.networkDictionary,
           },
           isNil,
diff --git a/packages/node/src/indexer/api.service.spec.ts b/packages/node/src/indexer/api.service.spec.ts
index 4360f7af54..a179c09f89 100644
--- a/packages/node/src/indexer/api.service.spec.ts
+++ b/packages/node/src/indexer/api.service.spec.ts
@@ -4,10 +4,12 @@
 import { EventEmitter2 } from '@nestjs/event-emitter';
 import { ApiPromise, WsProvider } from '@polkadot/api';
 import { ProjectNetworkV0_0_1 } from '@subql/common-substrate';
+import { ConnectionPoolService, NodeConfig } from '@subql/node-core';
 import { GraphQLSchema } from 'graphql';
 import { omit } from 'lodash';
 import { SubqueryProject } from '../configure/SubqueryProject';
 import { ApiService } from './api.service';
+import { ApiPromiseConnection } from './apiPromise.connection';
 
 jest.mock('@polkadot/api', () => {
   const ApiPromise = jest.fn();
@@ -23,7 +25,7 @@ jest.mock('@polkadot/api', () => {
 });
 
 const testNetwork: ProjectNetworkV0_0_1 = {
-  endpoint: 'wss://kusama.api.onfinality.io/public-ws',
+  endpoint: ['wss://kusama.api.onfinality.io/public-ws'],
   types: {
     TestType: 'u32',
   },
@@ -46,6 +48,13 @@ const testNetwork: ProjectNetworkV0_0_1 = {
   typesSpec: { spec3: { TestType6: 'test' } },
 };
 
+const nodeConfig = new NodeConfig({
+  subquery: 'asdf',
+  subqueryName: 'asdf',
+  networkEndpoint: ['wss://polkadot.api.onfinality.io/public-ws'],
+  dictionaryTimeout: 10,
+});
+
 function testSubqueryProject(): SubqueryProject {
   return {
     network: {
@@ -71,7 +80,12 @@ function testSubqueryProject(): SubqueryProject {
 describe('ApiService', () => {
   it('read custom types from project manifest', async () => {
     const project = testSubqueryProject();
-    const apiService = new ApiService(project, new EventEmitter2());
+    const apiService = new ApiService(
+      project,
+      new ConnectionPoolService<ApiPromiseConnection>(),
+      new EventEmitter2(),
+      nodeConfig,
+    );
     await apiService.init();
     const { version } = require('../../package.json');
     expect(WsProvider).toHaveBeenCalledWith(testNetwork.endpoint, 2500, {
@@ -91,7 +105,12 @@ describe('ApiService', () => {
     // Now after manifest 1.0.0, will use chainId instead of genesisHash
     (project.network as any).chainId = '0x';
 
-    const apiService = new ApiService(project, new EventEmitter2());
+    const apiService = new ApiService(
+      project,
+      new ConnectionPoolService<ApiPromiseConnection>(),
+      new EventEmitter2(),
+      nodeConfig,
+    );
 
     await expect(apiService.init()).rejects.toThrow();
   });
diff --git a/packages/node/src/indexer/api.service.test.ts b/packages/node/src/indexer/api.service.test.ts
index d1f9a20fe1..f357884052 100644
--- a/packages/node/src/indexer/api.service.test.ts
+++ b/packages/node/src/indexer/api.service.test.ts
@@ -20,7 +20,7 @@ const TEST_BLOCKHASH =
 
 const TEST_BLOCKNUMBER = 6721189; // kusama
 
-function testSubqueryProject(endpoint: string): SubqueryProject {
+function testSubqueryProject(endpoint: string[]): SubqueryProject {
   return {
     network: {
       endpoint,
@@ -54,7 +54,7 @@ describe('ApiService', () => {
       providers: [
         {
           provide: 'ISubqueryProject',
-          useFactory: () => testSubqueryProject(endpoint),
+          useFactory: () => testSubqueryProject([endpoint]),
         },
         ApiService,
       ],
@@ -70,7 +70,7 @@ describe('ApiService', () => {
 
   it('can instantiate api', async () => {
     const apiService = await prepareApiService();
-    const api = apiService.getApi();
+    const api = apiService.api;
 
     const apiAt = await api.at(TEST_BLOCKHASH);
     apiAt.registry;
@@ -82,7 +82,7 @@ describe('ApiService', () => {
 
   it('api query is locked at specified block', async () => {
     const apiService = await prepareApiService();
-    const api = apiService.getApi();
+    const api = apiService.api;
     const blockhash = await api.rpc.chain.getBlockHash(2);
     const validators = await api.query.session.validators.at(blockhash);
     const block = await api.rpc.chain.getBlock(blockhash);
@@ -102,7 +102,7 @@ describe('ApiService', () => {
 
   it('api query input is double map', async () => {
     const apiService = await prepareApiService();
-    const api = apiService.getApi();
+    const api = apiService.api;
     const blockhash = await api.rpc.chain.getBlockHash(6721189);
     const block = await api.rpc.chain.getBlock(blockhash);
     const mockBlock = wrapBlock(block, []) as unknown as SubstrateBlock;
@@ -128,7 +128,7 @@ describe('ApiService', () => {
     const apiService = await prepareApiService(
       'wss://polkadot.api.onfinality.io/public-ws',
     );
-    const api = apiService.getApi();
+    const api = apiService.api;
     const blockhash = await api.rpc.chain.getBlockHash(6721195);
     const block = await api.rpc.chain.getBlock(blockhash);
     const mockBlock = wrapBlock(block, []) as unknown as SubstrateBlock;
@@ -157,7 +157,7 @@ describe('ApiService', () => {
     const apiService = await prepareApiService(
       'wss://polkadot.api.onfinality.io/public-ws',
     );
-    const api = apiService.getApi();
+    const api = apiService.api;
     const blockhash = await api.rpc.chain.getBlockHash(5661443);
     const block = await api.rpc.chain.getBlock(blockhash);
     const mockBlock = wrapBlock(block, []) as unknown as SubstrateBlock;
@@ -178,7 +178,7 @@ describe('ApiService', () => {
 
   it.skip('api consts is swapped to the specified block', async () => {
     const apiService = await prepareApiService();
-    const api = apiService.getApi();
+    const api = apiService.api;
     // upgrade at 4401242 that maxNominatorRewardedPerValidator changed from 256 to 128
     let blockhash: BlockHash;
     const currentMaxNRPV =
@@ -203,7 +203,7 @@ describe('ApiService', () => {
 
   // it('.tx.*.*, .derive.*.* are removed', async () => {
   //   const apiService = await prepareApiService();
-  //   const api = apiService.getApi();
+  //   const api = apiService.api;
   //   const multiResults = await Promise.all([
   //     await api.query.system.account.at(TEST_BLOCKHASH, account1),
   //     await api.query.system.account.at(TEST_BLOCKHASH, account2),
@@ -227,7 +227,7 @@ describe('ApiService', () => {
   //
   // it.skip('xxx.xxx.multi with input parameter is a double map', async () => {
   //   const apiService = await prepareApiService();
-  //   const api = apiService.getApi();
+  //   const api = apiService.api;
   //   const patchedApi = await apiService.getPatchedApi(
   //     TEST_BLOCKHASH,
   //     TEST_BLOCKNUMBER,
@@ -254,7 +254,7 @@ describe('ApiService', () => {
   // it('api.queryMulti', async () => {
   //   const account = 'E7ncQKp4xayUoUdpraxBjT7NzLoayLJA4TuPcKKboBkJ5GH';
   //   const apiService = await prepareApiService();
-  //   const api = apiService.getApi();
+  //   const api = apiService.api;
   //   const patchedApi = await apiService.getPatchedApi(
   //     TEST_BLOCKHASH,
   //     TEST_BLOCKNUMBER,
@@ -288,7 +288,7 @@ describe('ApiService', () => {
   //
   // it.skip('api.rx.queryMulti is not supported', async () => {
   //   const apiService = await prepareApiService();
-  //   const api = apiService.getApi();
+  //   const api = apiService.api;
   //   const patchedApi = await apiService.getPatchedApi(
   //     TEST_BLOCKHASH,
   //     TEST_BLOCKNUMBER,
@@ -303,7 +303,7 @@ describe('ApiService', () => {
   //
   // it('support .entries', async () => {
   //   const apiService = await prepareApiService();
-  //   const api = apiService.getApi();
+  //   const api = apiService.api;
   //   const patchedApi = await apiService.getPatchedApi(
   //     TEST_BLOCKHASH,
   //     TEST_BLOCKNUMBER,
@@ -318,7 +318,7 @@ describe('ApiService', () => {
   //
   // it('support historic api rpc', async () => {
   //   const apiService = await prepareApiService();
-  //   const api = apiService.getApi();
+  //   const api = apiService.api;
   //
   //   const blockhash = await api.rpc.chain.getBlockHash(4401242);
   //   const patchedApi = await apiService.getPatchedApi(blockhash, 4401242);
@@ -337,7 +337,7 @@ describe('ApiService', () => {
   //
   // it('successful set block hash when continuous call api.xxx.xxx.at ', async () => {
   //   const apiService = await prepareApiService();
-  //   const api = apiService.getApi();
+  //   const api = apiService.api;
   //
   //   const blockhash1 = await api.rpc.chain.getBlockHash(1378036);
   //   let patchedApi = await apiService.getPatchedApi(blockhash1, 1378036);
@@ -359,7 +359,7 @@ describe('ApiService', () => {
   //
   it('support http provider', async () => {
     const apiService = await prepareApiService(HTTP_ENDPOINT);
-    const api = apiService.getApi();
+    const api = apiService.api;
     const blockhash = await api.rpc.chain.getBlockHash(1);
     const block = await api.rpc.chain.getBlock(blockhash);
     const mockBlock = wrapBlock(block, []) as unknown as SubstrateBlock;
@@ -377,7 +377,7 @@ describe('ApiService', () => {
     const apiService = await prepareApiService(
       'wss://moonbeam-alpha.api.onfinality.io/public-ws',
     );
-    const api = apiService.getApi();
+    const api = apiService.api;
 
     const blockNumber = 1545235;
     const blockhash = await api.rpc.chain.getBlockHash(blockNumber);
diff --git a/packages/node/src/indexer/api.service.ts b/packages/node/src/indexer/api.service.ts
index 341e2bff9d..e435e5f4d3 100644
--- a/packages/node/src/indexer/api.service.ts
+++ b/packages/node/src/indexer/api.service.ts
@@ -3,48 +3,62 @@
 
 import { Inject, Injectable, OnApplicationShutdown } from '@nestjs/common';
 import { EventEmitter2 } from '@nestjs/event-emitter';
-import { ApiPromise, WsProvider } from '@polkadot/api';
-import { ApiOptions, RpcMethodResult } from '@polkadot/api/types';
+import { ApiPromise } from '@polkadot/api';
+import { RpcMethodResult } from '@polkadot/api/types';
 import { RuntimeVersion } from '@polkadot/types/interfaces';
 import { AnyFunction, DefinitionRpcExt } from '@polkadot/types/types';
 import {
   IndexerEvent,
   NetworkMetadataPayload,
   getLogger,
+  NodeConfig,
+  profilerWrap,
+  ConnectionPoolService,
 } from '@subql/node-core';
 import { SubstrateBlock } from '@subql/types';
 import { SubqueryProject } from '../configure/SubqueryProject';
-import { ApiAt } from './types';
-import { HttpProvider } from './x-provider/http';
-
-// eslint-disable-next-line @typescript-eslint/no-var-requires
-const { version: packageVersion } = require('../../package.json');
+import * as SubstrateUtil from '../utils/substrate';
+import { ApiPromiseConnection } from './apiPromise.connection';
+import { ApiAt, BlockContent } from './types';
 
 const NOT_SUPPORT = (name: string) => () => {
   throw new Error(`${name}() is not supported`);
 };
 
 // https://github.com/polkadot-js/api/blob/12750bc83d8d7f01957896a80a7ba948ba3690b7/packages/rpc-provider/src/ws/index.ts#L43
-const RETRY_DELAY = 2_500;
+const MAX_RECONNECT_ATTEMPTS = 5;
 const TIMEOUT = 90 * 1000;
 
 const logger = getLogger('api');
 
 @Injectable()
 export class ApiService implements OnApplicationShutdown {
-  private api: ApiPromise;
+  private fetchBlocksBatches = SubstrateUtil.fetchBlocksBatches;
   private currentBlockHash: string;
   private currentBlockNumber: number;
-  private apiOption: ApiOptions;
   networkMeta: NetworkMetadataPayload;
 
   constructor(
     @Inject('ISubqueryProject') protected project: SubqueryProject,
+    private connectionPoolService: ConnectionPoolService<ApiPromiseConnection>,
     private eventEmitter: EventEmitter2,
+    private nodeConfig: NodeConfig,
   ) {}
 
   async onApplicationShutdown(): Promise<void> {
-    await Promise.all([this.api?.disconnect()]);
+    await this.connectionPoolService.onApplicationShutdown();
+  }
+
+  private metadataMismatchError(
+    metadata: string,
+    expected: string,
+    actual: string,
+  ): Error {
+    return Error(
+      `Value of ${metadata} does not match across all endpoints\n
+       Expected: ${expected}
+       Actual: ${actual}`,
+    );
   }
 
   async init(): Promise<ApiService> {
@@ -57,63 +71,89 @@ export class ApiService implements OnApplicationShutdown {
       process.exit(1);
     }
 
-    let provider: WsProvider | HttpProvider;
-    let throwOnConnect = false;
-
-    const headers = {
-      'User-Agent': `SubQuery-Node ${packageVersion}`,
-    };
-    if (network.endpoint.startsWith('ws')) {
-      provider = new WsProvider(
-        network.endpoint,
-        RETRY_DELAY,
-        headers,
-        TIMEOUT,
+    if (this.nodeConfig?.profiler) {
+      this.fetchBlocksBatches = profilerWrap(
+        SubstrateUtil.fetchBlocksBatches,
+        'SubstrateUtil',
+        'fetchBlocksBatches',
       );
-    } else if (network.endpoint.startsWith('http')) {
-      provider = new HttpProvider(network.endpoint, headers);
-      throwOnConnect = true;
     }
 
-    this.apiOption = {
-      provider,
-      throwOnConnect,
-      noInitWarn: true,
-      ...chainTypes,
-    };
-    this.api = await ApiPromise.create(this.apiOption);
-
-    this.eventEmitter.emit(IndexerEvent.ApiConnected, { value: 1 });
-    this.api.on('connected', () => {
-      this.eventEmitter.emit(IndexerEvent.ApiConnected, { value: 1 });
-    });
-    this.api.on('disconnected', () => {
-      this.eventEmitter.emit(IndexerEvent.ApiConnected, { value: 0 });
-    });
-
-    this.networkMeta = {
-      chain: this.api.runtimeChain.toString(),
-      specName: this.api.runtimeVersion.specName.toString(),
-      genesisHash: this.api.genesisHash.toString(),
-    };
-
-    if (network.chainId && network.chainId !== this.networkMeta.genesisHash) {
-      const err = new Error(
-        `Network chainId doesn't match expected genesisHash. Your SubQuery project is expecting to index data from "${
-          network.chainId ?? network.genesisHash
-        }", however the endpoint that you are connecting to is different("${
-          this.networkMeta.genesisHash
-        }). Please check that the RPC endpoint is actually for your desired network or update the genesisHash.`,
-      );
-      logger.error(err, err.message);
-      throw err;
-    }
+    const connections: ApiPromiseConnection[] = [];
+
+    await Promise.all(
+      network.endpoint.map(async (endpoint, i) => {
+        const connection = await ApiPromiseConnection.create(endpoint, {
+          chainTypes,
+        });
+        const api = connection.api;
+
+        this.eventEmitter.emit(IndexerEvent.ApiConnected, {
+          value: 1,
+          apiIndex: i,
+          endpoint: endpoint,
+        });
+
+        api.on('connected', () => {
+          this.eventEmitter.emit(IndexerEvent.ApiConnected, {
+            value: 1,
+            apiIndex: i,
+            endpoint: endpoint,
+          });
+        });
+        api.on('disconnected', () => {
+          this.eventEmitter.emit(IndexerEvent.ApiConnected, {
+            value: 0,
+            apiIndex: i,
+            endpoint: endpoint,
+          });
+          this.connectionPoolService.handleApiDisconnects(i, endpoint);
+        });
+
+        if (!this.networkMeta) {
+          this.networkMeta = {
+            chain: api.runtimeChain.toString(),
+            specName: api.runtimeVersion.specName.toString(),
+            genesisHash: api.genesisHash.toString(),
+          };
+
+          if (
+            network.chainId &&
+            network.chainId !== this.networkMeta.genesisHash
+          ) {
+            const err = new Error(
+              `Network chainId doesn't match expected genesisHash. Your SubQuery project is expecting to index data from "${
+                network.chainId ?? network.genesisHash
+              }", however the endpoint that you are connecting to is different("${
+                this.networkMeta.genesisHash
+              }). Please check that the RPC endpoint is actually for your desired network or update the genesisHash.`,
+            );
+            logger.error(err, err.message);
+            throw err;
+          }
+        } else {
+          const genesisHash = api.genesisHash.toString();
+          if (this.networkMeta.genesisHash !== genesisHash) {
+            throw this.metadataMismatchError(
+              'Genesis Hash',
+              this.networkMeta.genesisHash,
+              genesisHash,
+            );
+          }
+        }
+
+        logger.info(`Connected to ${endpoint} successfully`);
+
+        connections.push(connection);
+      }),
+    );
 
+    this.connectionPoolService.addBatchToConnections(connections);
     return this;
   }
 
-  getApi(): ApiPromise {
-    return this.api;
+  get api(): ApiPromise {
+    return this.connectionPoolService.api.api;
   }
 
   async getPatchedApi(
@@ -123,11 +163,12 @@ export class ApiService implements OnApplicationShutdown {
     this.currentBlockHash = block.block.hash.toString();
     this.currentBlockNumber = block.block.header.number.toNumber();
 
-    const apiAt = (await this.api.at(
+    const api = this.api;
+    const apiAt = (await api.at(
       this.currentBlockHash,
       runtimeVersion,
     )) as ApiAt;
-    this.patchApiRpc(this.api, apiAt);
+    this.patchApiRpc(api, apiAt);
     return apiAt;
   }
 
@@ -211,4 +252,55 @@ export class ApiService implements OnApplicationShutdown {
 
     return `api.rpc.${ext?.section ?? '*'}.${ext?.method ?? '*'}`;
   }
+
+  private async fetchBlocksFromFirstAvailableEndpoint(
+    batch: number[],
+    overallSpecVer?: number,
+  ): Promise<BlockContent[]> {
+    let reconnectAttempts = 0;
+    while (reconnectAttempts < MAX_RECONNECT_ATTEMPTS) {
+      try {
+        const blocks = await this.fetchBlocksBatches(
+          this.api,
+          batch,
+          overallSpecVer,
+        );
+        return blocks;
+      } catch (e) {
+        logger.error(e, 'Failed to fetch blocks');
+        reconnectAttempts++;
+      }
+    }
+    throw new Error(
+      `Maximum number of retries (${MAX_RECONNECT_ATTEMPTS}) reached.`,
+    );
+  }
+
+  async fetchBlocks(
+    blockNums: number[],
+    overallSpecVer?: number,
+  ): Promise<BlockContent[]> {
+    const api = this.api;
+    try {
+      const blocks = await this.fetchBlocksBatches(
+        api,
+        blockNums,
+        overallSpecVer,
+      );
+      return blocks;
+    } catch (e) {
+      logger.error(
+        e,
+        `Failed to fetch blocks ${blockNums[0]}...${
+          blockNums[blockNums.length - 1]
+        }`,
+      );
+
+      const blocks = await this.fetchBlocksFromFirstAvailableEndpoint(
+        blockNums,
+        overallSpecVer,
+      );
+      return blocks;
+    }
+  }
 }
diff --git a/packages/node/src/indexer/apiPromise.connection.ts b/packages/node/src/indexer/apiPromise.connection.ts
index 7e90950beb..1552570a9c 100644
--- a/packages/node/src/indexer/apiPromise.connection.ts
+++ b/packages/node/src/indexer/apiPromise.connection.ts
@@ -1,11 +1,58 @@
 // Copyright 2020-2022 OnFinality Limited authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { getLogger } from '@subql/node-core';
+import { ApiPromise, WsProvider } from '@polkadot/api';
+import { RegisteredTypes } from '@polkadot/types/types';
+import { ApiConnection } from '@subql/node-core';
+import { HttpProvider } from './x-provider/http';
 
-const logger = getLogger('connection');
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const { version: packageVersion } = require('../../package.json');
+
+const RETRY_DELAY = 2_500;
+
+export class ApiPromiseConnection implements ApiConnection {
+  constructor(private _api: ApiPromise) {}
+
+  static async create(
+    endpoint: string,
+    args: { chainTypes: RegisteredTypes },
+  ): Promise<ApiPromiseConnection> {
+    let provider: WsProvider | HttpProvider;
+    let throwOnConnect = false;
+
+    const headers = {
+      'User-Agent': `SubQuery-Node ${packageVersion}`,
+    };
+
+    if (endpoint.startsWith('ws')) {
+      provider = new WsProvider(endpoint, RETRY_DELAY, headers);
+    } else if (endpoint.startsWith('http')) {
+      provider = new HttpProvider(endpoint, headers);
+      throwOnConnect = true;
+    }
+
+    const apiOption = {
+      provider,
+      throwOnConnect,
+      noInitWarn: true,
+      ...args.chainTypes,
+    };
+    const api = await ApiPromise.create(apiOption);
+    return new ApiPromiseConnection(api);
+  }
+
+  get api(): ApiPromise {
+    return this._api;
+  }
+
+  async apiConnect(): Promise<void> {
+    await this._api.connect();
+  }
+  async apiDisconnect(): Promise<void> {
+    await this._api.disconnect();
+  }
 
-export class ApiPromiseConnection {
   static handleError(e: Error): Error {
     let formatted_error: Error;
     if (e.message.startsWith(`No response received from RPC endpoint in`)) {
diff --git a/packages/node/src/indexer/blockDispatcher/base-block-dispatcher.ts b/packages/node/src/indexer/blockDispatcher/base-block-dispatcher.ts
index b50775a367..7aa114f1d4 100644
--- a/packages/node/src/indexer/blockDispatcher/base-block-dispatcher.ts
+++ b/packages/node/src/indexer/blockDispatcher/base-block-dispatcher.ts
@@ -4,7 +4,13 @@
 import assert from 'assert';
 import { EventEmitter2 } from '@nestjs/event-emitter';
 import { hexToU8a, u8aEq } from '@polkadot/util';
-import { getLogger, IndexerEvent, IQueue, NodeConfig, SmartBatchService } from '@subql/node-core';
+import {
+  getLogger,
+  IndexerEvent,
+  IQueue,
+  NodeConfig,
+  SmartBatchService,
+} from '@subql/node-core';
 import { ProjectService } from '../project.service';
 import { RuntimeService } from '../runtime/runtimeService';
 
diff --git a/packages/node/src/indexer/blockDispatcher/block-dispatcher.service.ts b/packages/node/src/indexer/blockDispatcher/block-dispatcher.service.ts
index a55aa13866..f1a2630e03 100644
--- a/packages/node/src/indexer/blockDispatcher/block-dispatcher.service.ts
+++ b/packages/node/src/indexer/blockDispatcher/block-dispatcher.service.ts
@@ -9,7 +9,6 @@ import {
   NodeConfig,
   IndexerEvent,
   delay,
-  profilerWrap,
   AutoQueue,
   Queue,
   waitForBatchSize,
@@ -17,11 +16,11 @@ import {
   SmartBatchService,
 } from '@subql/node-core';
 import { last } from 'lodash';
-import * as SubstrateUtil from '../../utils/substrate';
 import { ApiService } from '../api.service';
 import { IndexerManager } from '../indexer.manager';
 import { ProjectService } from '../project.service';
 import { RuntimeService } from '../runtime/runtimeService';
+import { BlockContent } from '../types';
 import { BaseBlockDispatcher } from './base-block-dispatcher';
 
 const logger = getLogger('BlockDispatcherService');
@@ -39,7 +38,6 @@ export class BlockDispatcherService
   private fetching = false;
   private isShutdown = false;
   // private getRuntimeVersion: GetRuntimeVersion;
-  private fetchBlocksBatches = SubstrateUtil.fetchBlocksBatches;
 
   constructor(
     private apiService: ApiService,
@@ -57,13 +55,6 @@ export class BlockDispatcherService
       smartBatchService,
     );
     this.processQueue = new AutoQueue(nodeConfig.batchSize * 3);
-    if (this.nodeConfig.profiler) {
-      this.fetchBlocksBatches = profilerWrap(
-        SubstrateUtil.fetchBlocksBatches,
-        'SubstrateUtil',
-        'fetchBlocksBatches',
-      );
-    }
   }
 
   // eslint-disable-next-line @typescript-eslint/require-await
@@ -168,8 +159,7 @@ export class BlockDispatcherService
           await memoryLock.waitForUnlock();
         }
 
-        const blocks = await this.fetchBlocksBatches(
-          this.apiService.getApi(),
+        const blocks = await this.apiService.fetchBlocks(
           blockNums,
           specChanged ? undefined : this.runtimeService.parentSpecVersion,
         );
@@ -182,6 +172,7 @@ export class BlockDispatcherService
           bufferedHeight > this._latestBufferedHeight ||
           this.queue.peek() < Math.min(...blockNums)
         ) {
+          logger.info(`${this.queue.peek()} - ${Math.min(...blockNums)}`);
           logger.info(`Queue was reset for new DS, discarding fetched blocks`);
           continue;
         }
diff --git a/packages/node/src/indexer/dictionary.service.test.ts b/packages/node/src/indexer/dictionary.service.test.ts
index 796535dc32..4c8b19b061 100644
--- a/packages/node/src/indexer/dictionary.service.test.ts
+++ b/packages/node/src/indexer/dictionary.service.test.ts
@@ -21,7 +21,7 @@ function testSubqueryProject(): SubqueryProject {
 const nodeConfig = new NodeConfig({
   subquery: 'asdf',
   subqueryName: 'asdf',
-  networkEndpoint: 'wss://polkadot.api.onfinality.io/public-ws',
+  networkEndpoint: ['wss://polkadot.api.onfinality.io/public-ws'],
   dictionaryTimeout: 10,
 });
 
diff --git a/packages/node/src/indexer/ds-processor.service.spec.ts b/packages/node/src/indexer/ds-processor.service.spec.ts
index f2f3838d0c..3d52f947c9 100644
--- a/packages/node/src/indexer/ds-processor.service.spec.ts
+++ b/packages/node/src/indexer/ds-processor.service.spec.ts
@@ -15,7 +15,7 @@ function getTestProject(
   return {
     network: {
       genesisHash: '0x',
-      endpoint: 'wss://polkadot.api.onfinality.io/public-ws',
+      endpoint: ['wss://polkadot.api.onfinality.io/public-ws'],
     },
     dataSources: [
       {
diff --git a/packages/node/src/indexer/fetch.module.ts b/packages/node/src/indexer/fetch.module.ts
index be79c40619..fef8d9bb3f 100644
--- a/packages/node/src/indexer/fetch.module.ts
+++ b/packages/node/src/indexer/fetch.module.ts
@@ -9,7 +9,8 @@ import {
   StoreService,
   PoiService,
   NodeConfig,
-  SmartBatchService
+  ConnectionPoolService,
+  SmartBatchService,
 } from '@subql/node-core';
 
 import { SubqueryProject } from '../configure/SubqueryProject';
@@ -33,6 +34,7 @@ import { UnfinalizedBlocksService } from './unfinalizedBlocks.service';
     StoreService,
     ApiService,
     IndexerManager,
+    ConnectionPoolService,
     {
       provide: SmartBatchService,
       useFactory: (nodeConfig: NodeConfig) => {
diff --git a/packages/node/src/indexer/fetch.service.spec.ts b/packages/node/src/indexer/fetch.service.spec.ts
index cda09bdcf6..91b75466e9 100644
--- a/packages/node/src/indexer/fetch.service.spec.ts
+++ b/packages/node/src/indexer/fetch.service.spec.ts
@@ -15,7 +15,7 @@ import {
   NodeConfig,
   Dictionary,
   MetadataRepo,
-  SmartBatchService
+  SmartBatchService,
 } from '@subql/node-core';
 import { GraphQLSchema } from 'graphql';
 import { difference, range } from 'lodash';
@@ -40,7 +40,7 @@ jest.mock('../utils/substrate', () =>
 const nodeConfig = new NodeConfig({
   subquery: 'asdf',
   subqueryName: 'asdf',
-  networkEndpoint: 'wss://polkadot.api.onfinality.io/public-ws',
+  networkEndpoint: ['wss://polkadot.api.onfinality.io/public-ws'],
   dictionaryTimeout: 10,
 });
 
@@ -275,7 +275,7 @@ function mockDictionaryService3(): DictionaryService {
 function testSubqueryProject(): SubqueryProject {
   return {
     network: {
-      endpoint: 'wss://polkadot.api.onfinality.io/public-ws',
+      endpoint: ['wss://polkadot.api.onfinality.io/public-ws'],
     },
     chainTypes: {
       types: {
@@ -417,10 +417,8 @@ describe('FetchService', () => {
       project,
     );
     const pendingInit = fetchService.init(1);
-    expect(
-      apiService.getApi().rpc.chain.getFinalizedHead,
-    ).toHaveBeenCalledTimes(1);
-    expect(apiService.getApi().rpc.chain.getHeader).toHaveBeenCalledTimes(1);
+    expect(apiService.api.rpc.chain.getFinalizedHead).toHaveBeenCalledTimes(1);
+    expect(apiService.api.rpc.chain.getHeader).toHaveBeenCalledTimes(1);
     await pendingInit;
     fetchService.onApplicationShutdown();
   });
diff --git a/packages/node/src/indexer/fetch.service.test.ts b/packages/node/src/indexer/fetch.service.test.ts
index 2a69e8912a..129fc2f05a 100644
--- a/packages/node/src/indexer/fetch.service.test.ts
+++ b/packages/node/src/indexer/fetch.service.test.ts
@@ -17,7 +17,7 @@ import {
   NodeConfig,
   PoiService,
   StoreService,
-  SmartBatchService
+  SmartBatchService,
 } from '@subql/node-core';
 import { GraphQLSchema } from 'graphql';
 import { Sequelize } from 'sequelize';
@@ -41,7 +41,7 @@ const HTTP_ENDPOINT = 'https://polkadot.api.onfinality.io/public';
 function testSubqueryProject(): SubqueryProject {
   return {
     network: {
-      endpoint: WS_ENDPOINT,
+      endpoint: [WS_ENDPOINT],
     },
     chainTypes: {
       types: {
@@ -97,7 +97,7 @@ jest.setTimeout(200000);
 const nodeConfig = new NodeConfig({
   subquery: 'asdf',
   subqueryName: 'asdf',
-  networkEndpoint: WS_ENDPOINT,
+  networkEndpoint: [WS_ENDPOINT],
   dictionaryTimeout: 10,
   batchSize: 5,
 });
@@ -502,7 +502,7 @@ describe('FetchService', () => {
     const indexerManager = mockIndexerManager();
     //set dictionary to different network
     //set to a kusama network and use polkadot dictionary
-    project.network.endpoint = 'wss://kusama.api.onfinality.io/public-ws';
+    project.network.endpoint = ['wss://kusama.api.onfinality.io/public-ws'];
     project.network.dictionary =
       'https://api.subquery.network/sq/subquery/polkadot-dictionary';
     project.dataSources = [
@@ -728,8 +728,9 @@ describe('FetchService', () => {
     await runtimeService.getSpecVersion(10337859);
     const specVersionMap = (runtimeService as any).specVersionMap;
     // If the last finalized block specVersion are same,  we expect it will update the specVersion map
-    const latestSpecVersion =
-      await fetchService.api.rpc.state.getRuntimeVersion();
+    const latestSpecVersion = await fetchService
+      .api()
+      .rpc.state.getRuntimeVersion();
     // This should be match if dictionary is fully synced
     expect(Number(specVersionMap[specVersionMap.length - 1].id)).toBe(
       latestSpecVersion.specVersion.toNumber(),
@@ -791,7 +792,7 @@ describe('FetchService', () => {
     const project = testSubqueryProject();
 
     project.dataSources[0].startBlock = 3467085;
-    project.network.endpoint = 'wss://karura-rpc-0.aca-api.network';
+    project.network.endpoint = ['wss://karura-rpc-0.aca-api.network'];
 
     const indexerManager = mockIndexerManager();
 
diff --git a/packages/node/src/indexer/fetch.service.ts b/packages/node/src/indexer/fetch.service.ts
index c6a339dbf3..e6b4d6eb64 100644
--- a/packages/node/src/indexer/fetch.service.ts
+++ b/packages/node/src/indexer/fetch.service.ts
@@ -118,8 +118,8 @@ export class FetchService implements OnApplicationShutdown {
     this.isShutdown = true;
   }
 
-  get api(): ApiPromise {
-    return this.apiService.getApi();
+  api(): ApiPromise {
+    return this.apiService.api;
   }
 
   async syncDynamicDatascourcesFromMeta(): Promise<void> {
@@ -136,7 +136,7 @@ export class FetchService implements OnApplicationShutdown {
         isRuntimeDataSourceV0_2_0(ds) ||
         !(ds as RuntimeDataSourceV0_0_1).filter?.specName ||
         (ds as RuntimeDataSourceV0_0_1).filter.specName ===
-          this.api.runtimeVersion.specName.toString(),
+          this.api().runtimeVersion.specName.toString(),
     );
 
     // Only run the ds that is equal or less than startBlock
@@ -242,8 +242,8 @@ export class FetchService implements OnApplicationShutdown {
         this.project.network.bypassBlocks,
       ).filter((blk) => blk >= startHeight);
     }
-    if (this.api) {
-      const CHAIN_INTERVAL = calcInterval(this.api)
+    if (this.api()) {
+      const CHAIN_INTERVAL = calcInterval(this.api())
         .muln(INTERVAL_PERCENT)
         .toNumber();
 
@@ -323,8 +323,10 @@ export class FetchService implements OnApplicationShutdown {
       return;
     }
     try {
-      const finalizedHash = await this.api.rpc.chain.getFinalizedHead();
-      const finalizedHeader = await this.api.rpc.chain.getHeader(finalizedHash);
+      const finalizedHash = await this.api().rpc.chain.getFinalizedHead();
+      const finalizedHeader = await this.api().rpc.chain.getHeader(
+        finalizedHash,
+      );
       this.unfinalizedBlocksService.registerFinalizedBlock(finalizedHeader);
       const currentFinalizedHeight = finalizedHeader.number.toNumber();
       if (this.latestFinalizedHeight !== currentFinalizedHeight) {
@@ -346,7 +348,7 @@ export class FetchService implements OnApplicationShutdown {
       return;
     }
     try {
-      const bestHeader = await this.api.rpc.chain.getHeader();
+      const bestHeader = await this.api().rpc.chain.getHeader();
       const currentBestHeight = bestHeader.number.toNumber();
       if (this.latestBestHeight !== currentBestHeight) {
         this.latestBestHeight = currentBestHeight;
@@ -606,7 +608,7 @@ export class FetchService implements OnApplicationShutdown {
     if (dictionary !== undefined) {
       const { _metadata: metaData } = dictionary;
 
-      if (metaData.genesisHash !== this.api.genesisHash.toString()) {
+      if (metaData.genesisHash !== this.api().genesisHash.toString()) {
         logger.error(
           'The dictionary that you have specified does not match the chain you are indexing, it will be ignored. Please update your project manifest to reference the correct dictionary',
         );
diff --git a/packages/node/src/indexer/indexer.manager.spec.ts b/packages/node/src/indexer/indexer.manager.spec.ts
index e1bd0d1497..8681d715aa 100644
--- a/packages/node/src/indexer/indexer.manager.spec.ts
+++ b/packages/node/src/indexer/indexer.manager.spec.ts
@@ -11,11 +11,13 @@ import {
   PoiService,
   MmrService,
   NodeConfig,
+  ConnectionPoolService,
 } from '@subql/node-core';
 import { GraphQLSchema } from 'graphql';
 import { Sequelize } from 'sequelize';
 import { SubqueryProject } from '../configure/SubqueryProject';
 import { ApiService } from './api.service';
+import { ApiPromiseConnection } from './apiPromise.connection';
 import { DsProcessorService } from './ds-processor.service';
 import { DynamicDsService } from './dynamic-ds.service';
 import { IndexerManager } from './indexer.manager';
@@ -54,13 +56,13 @@ jest.setTimeout(200000);
 const nodeConfig = new NodeConfig({
   subquery: 'asdf',
   subqueryName: 'asdf',
-  networkEndpoint: 'wss://polkadot.api.onfinality.io/public-ws',
+  networkEndpoint: ['wss://polkadot.api.onfinality.io/public-ws'],
 });
 
 function testSubqueryProject_1(): SubqueryProject {
   return {
     network: {
-      endpoint: 'wss://polkadot.api.onfinality.io/public-ws',
+      endpoint: ['wss://polkadot.api.onfinality.io/public-ws'],
     },
     dataSources: [
       {
@@ -98,7 +100,7 @@ function testSubqueryProject_1(): SubqueryProject {
 function testSubqueryProject_2(): SubqueryProject {
   return {
     network: {
-      endpoint: 'wss://polkadot.api.onfinality.io/public-ws',
+      endpoint: ['wss://polkadot.api.onfinality.io/public-ws'],
       dictionary: `https://api.subquery.network/sq/subquery/dictionary-polkadot`,
       genesisHash:
         '0x91b171bb158e2d3848fa23a9f1c25182fb8e20313b2c1eb49219da7a70ce90c3',
@@ -126,11 +128,17 @@ function testSubqueryProject_2(): SubqueryProject {
 
 function createIndexerManager(
   project: SubqueryProject,
+  connectionPoolService: ConnectionPoolService<ApiPromiseConnection>,
   nodeConfig: NodeConfig,
 ): IndexerManager {
   const sequilize = new Sequelize();
   const eventEmitter = new EventEmitter2();
-  const apiService = new ApiService(project, eventEmitter);
+  const apiService = new ApiService(
+    project,
+    connectionPoolService,
+    eventEmitter,
+    nodeConfig,
+  );
   const dsProcessorService = new DsProcessorService(project, nodeConfig);
   const dynamicDsService = new DynamicDsService(dsProcessorService, project);
 
@@ -188,14 +196,22 @@ describe('IndexerManager', () => {
   });
 
   xit('should be able to start the manager (v0.0.1)', async () => {
-    indexerManager = createIndexerManager(testSubqueryProject_1(), nodeConfig);
+    indexerManager = createIndexerManager(
+      testSubqueryProject_1(),
+      new ConnectionPoolService<ApiPromiseConnection>(),
+      nodeConfig,
+    );
     await expect(indexerManager.start()).resolves.toBe(undefined);
 
     expect(Object.keys((indexerManager as any).vms).length).toBe(1);
   });
 
   xit('should be able to start the manager (v0.2.0)', async () => {
-    indexerManager = createIndexerManager(testSubqueryProject_2(), nodeConfig);
+    indexerManager = createIndexerManager(
+      testSubqueryProject_2(),
+      new ConnectionPoolService<ApiPromiseConnection>(),
+      nodeConfig,
+    );
     await expect(indexerManager.start()).resolves.toBe(undefined);
 
     expect(Object.keys((indexerManager as any).vms).length).toBe(1);
diff --git a/packages/node/src/indexer/indexer.manager.ts b/packages/node/src/indexer/indexer.manager.ts
index fd5f300bb9..a065d2da19 100644
--- a/packages/node/src/indexer/indexer.manager.ts
+++ b/packages/node/src/indexer/indexer.manager.ts
@@ -70,8 +70,6 @@ export class IndexerManager {
     private projectService: ProjectService,
   ) {
     logger.info('indexer manager start');
-
-    this.api = this.apiService.getApi();
   }
 
   @profiler(yargsOptions.argv.profiler)
@@ -83,6 +81,7 @@ export class IndexerManager {
     operationHash: Uint8Array;
     reindexBlockHeight: number;
   }> {
+    this.api = this.apiService.api;
     const { block } = blockContent;
     let dynamicDsCreated = false;
     let reindexBlockHeight = null;
diff --git a/packages/node/src/indexer/indexer.module.ts b/packages/node/src/indexer/indexer.module.ts
index e0c1a5d01a..d2f783a7eb 100644
--- a/packages/node/src/indexer/indexer.module.ts
+++ b/packages/node/src/indexer/indexer.module.ts
@@ -3,9 +3,16 @@
 
 import { Module } from '@nestjs/common';
 import { EventEmitter2 } from '@nestjs/event-emitter';
-import { StoreService, PoiService, MmrService } from '@subql/node-core';
+import {
+  StoreService,
+  PoiService,
+  MmrService,
+  NodeConfig,
+  ConnectionPoolService,
+} from '@subql/node-core';
 import { SubqueryProject } from '../configure/SubqueryProject';
 import { ApiService } from './api.service';
+import { ApiPromiseConnection } from './apiPromise.connection';
 import { DsProcessorService } from './ds-processor.service';
 import { DynamicDsService } from './dynamic-ds.service';
 import { IndexerManager } from './indexer.manager';
@@ -19,17 +26,30 @@ import { WorkerService } from './worker/worker.service';
   providers: [
     IndexerManager,
     StoreService,
+    ConnectionPoolService,
     {
       provide: ApiService,
       useFactory: async (
         project: SubqueryProject,
+        connectionPoolService: ConnectionPoolService<ApiPromiseConnection>,
         eventEmitter: EventEmitter2,
+        nodeConfig: NodeConfig,
       ) => {
-        const apiService = new ApiService(project, eventEmitter);
+        const apiService = new ApiService(
+          project,
+          connectionPoolService,
+          eventEmitter,
+          nodeConfig,
+        );
         await apiService.init();
         return apiService;
       },
-      inject: ['ISubqueryProject', EventEmitter2],
+      inject: [
+        'ISubqueryProject',
+        ConnectionPoolService,
+        EventEmitter2,
+        NodeConfig,
+      ],
     },
     SandboxService,
     DsProcessorService,
diff --git a/packages/node/src/indexer/project.service.ts b/packages/node/src/indexer/project.service.ts
index 6da398d200..bfec95d316 100644
--- a/packages/node/src/indexer/project.service.ts
+++ b/packages/node/src/indexer/project.service.ts
@@ -98,7 +98,7 @@ export class ProjectService {
     // Do extra work on main thread to setup stuff
     this.project.dataSources = await generateTimestampReferenceForBlockFilters(
       this.project.dataSources,
-      this.apiService.getApi(),
+      this.apiService.api,
     );
     if (isMainThread) {
       this._schema = await this.ensureProject();
@@ -383,7 +383,7 @@ export class ProjectService {
       (ds) =>
         !ds.filter?.specName ||
         ds.filter.specName ===
-          this.apiService.getApi().runtimeVersion.specName.toString(),
+          this.apiService.api.runtimeVersion.specName.toString(),
     );
   }
 
diff --git a/packages/node/src/indexer/runtime/base-runtime.service.ts b/packages/node/src/indexer/runtime/base-runtime.service.ts
index 48b7fd1f22..9091e0d326 100644
--- a/packages/node/src/indexer/runtime/base-runtime.service.ts
+++ b/packages/node/src/indexer/runtime/base-runtime.service.ts
@@ -49,7 +49,7 @@ export abstract class BaseRuntimeService {
   }
 
   get api(): ApiPromise {
-    return this.apiService.getApi();
+    return this.apiService.api;
   }
 
   getSpecFromMap(
diff --git a/packages/node/src/indexer/sandbox.service.ts b/packages/node/src/indexer/sandbox.service.ts
index 191e6633c1..b33e3090e6 100644
--- a/packages/node/src/indexer/sandbox.service.ts
+++ b/packages/node/src/indexer/sandbox.service.ts
@@ -41,7 +41,7 @@ export class SandboxService {
     }
     processor.freeze(api, 'api');
     if (this.nodeConfig.unsafe) {
-      processor.freeze(this.apiService.getApi(), 'unsafeApi');
+      processor.freeze(this.apiService.api, 'unsafeApi');
     }
     return processor;
   }
diff --git a/packages/node/src/indexer/unfinalizedBlocks.service.ts b/packages/node/src/indexer/unfinalizedBlocks.service.ts
index 2f87414bc6..4db736f507 100644
--- a/packages/node/src/indexer/unfinalizedBlocks.service.ts
+++ b/packages/node/src/indexer/unfinalizedBlocks.service.ts
@@ -77,7 +77,7 @@ export class UnfinalizedBlocksService {
   }
 
   private get api(): ApiPromise {
-    return this.apiService.getApi();
+    return this.apiService.api;
   }
 
   private get finalizedBlockNumber(): number {
diff --git a/packages/node/src/indexer/worker/worker.service.ts b/packages/node/src/indexer/worker/worker.service.ts
index 6d3db4d243..70702c332d 100644
--- a/packages/node/src/indexer/worker/worker.service.ts
+++ b/packages/node/src/indexer/worker/worker.service.ts
@@ -4,7 +4,6 @@
 import { threadId } from 'node:worker_threads';
 import { Injectable } from '@nestjs/common';
 import { NodeConfig, getLogger, AutoQueue, memoryLock } from '@subql/node-core';
-import { fetchBlocksBatches } from '../../utils/substrate';
 import { ApiService } from '../api.service';
 import { SpecVersion } from '../dictionary.service';
 import { IndexerManager } from '../indexer.manager';
@@ -73,8 +72,7 @@ export class WorkerService {
             logger.debug(`memory lock wait time: ${end - start}ms`);
           }
 
-          const [block] = await fetchBlocksBatches(
-            this.apiService.getApi(),
+          const [block] = await this.apiService.fetchBlocks(
             [height],
             specChanged
               ? undefined
diff --git a/packages/node/src/utils/substrate.ts b/packages/node/src/utils/substrate.ts
index 7aa5ae768a..6033e2ccc5 100644
--- a/packages/node/src/utils/substrate.ts
+++ b/packages/node/src/utils/substrate.ts
@@ -326,6 +326,7 @@ export async function fetchBlocksBatches(
   blockArray: number[],
   overallSpecVer?: number,
 ): Promise<BlockContent[]> {
+  //await api.disconnect();
   const blocks = await fetchBlocksArray(api, blockArray);
   const blockHashs = blocks.map((b) => b.block.header.hash);
   const parentBlockHashs = blocks.map((b) => b.block.header.parentHash);
diff --git a/packages/query/src/configure/config.ts b/packages/query/src/configure/config.ts
index 9ea73c1564..a5aca82069 100644
--- a/packages/query/src/configure/config.ts
+++ b/packages/query/src/configure/config.ts
@@ -7,6 +7,6 @@ export class Config {
   constructor(private readonly store: Record<never, never>) {}
 
   get<T>(key: string, defaultValue?: T): T {
-    return process.env[key.toUpperCase()] ?? get(this.store, key, defaultValue);
+    return (process.env[key.toUpperCase()] as unknown as T) ?? get(this.store, key, defaultValue);
   }
 }
diff --git a/yarn.lock b/yarn.lock
index f431547ed6..46a6708907 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3987,6 +3987,7 @@ __metadata:
     oclif: ^2.4.4
     rimraf: ^3.0.2
     simple-git: ^3.12.0
+    terser-webpack-plugin: ^5.3.7
     ts-loader: ^9.2.6
     tslib: ^2.3.1
     typechain: 8.1.1
@@ -4195,7 +4196,6 @@ __metadata:
     prom-client: ^14.0.1
     sequelize: 6.28.0
     source-map: ^0.7.4
-    terser-webpack-plugin: ^5.3.7
     vm2: ^3.9.9
     yargs: ^16.2.0
   languageName: unknown