Bundler API - Using SDK

Required SDK version: ^v4.59.1

The @account-kit/infra library enables direct interaction with Alchemy's ERC-4337 bundler for advanced UserOperation management. The alchemyFeeEstimator function leverages underlying APIs, including rundler_maxPriorityFeePerGas and eth_estimateUserOperation, to estimate gas fees for UserOperations. Below are examples demonstrating how to estimate and send a UserOperation and how to retrieve a UserOperation by its hash using low-level Bundler APIs.

config.ts

import { alchemy, sepolia } from "@account-kit/infra";
 
const YOUR_API_KEY = "<YOUR_API_KEY>";
export const YOUR_PRIVATE_KEY = "<YOUR_PRIVATE_KEY>";
export const chain = sepolia;
 
export const transport = alchemy({
  apiKey: YOUR_API_KEY,
});

estimateAndSendUserOperation.ts

import { alchemyFeeEstimator } from "@account-kit/infra";
import { createModularAccountV2Client } from "@account-kit/smart-contracts";
import { LocalAccountSigner } from "@aa-sdk/core";
import { entryPoint07Address } from "viem/account-abstraction";
import {
  chain,
  transport
  YOUR_PRIVATE_KEY,
} from "./config.ts";
 
export async function estimateAndSendUserOperation() {
  const client = await createModularAccountV2Client({
    signer: LocalAccountSigner.privateKeyToAccountSigner(YOUR_PRIVATE_KEY),
    chain,
    transport,
    feeEstimator: alchemyFeeEstimator(transport),
  });
 
  try {
    let uo = await client.buildUserOperation({
      uo: {
        data: "0x",
        target: "0x0000000000000000000000000000000000000000",
      },
    });
    const uoWithSig = await client.signUserOperation({ uoStruct: uo });
    const sendResult = await client.sendRawUserOperation(
      uoWithSig,
      entryPoint07Address,
    );
    await client.waitForUserOperationTransaction({
      hash: sendResult,
      retries: {
        intervalMs: 100,
        maxRetries: 600,
        multiplier: 0,
      },
    });
    const receipt = await client.getUserOperationReceipt(sendResult);
    console.log("UserOperation receipt:", receipt);
  } catch (error) {
    console.error("Error processing UserOperation:", error);
  }
}

getUserOperationByHash.ts

import { createAlchemyPublicRpcClient } from "@account-kit/infra";
import { chain, transport } from "./config.ts";
import type { Hash } from "viem";
 
export async function getUserOperationByHash(uoHash: Hash) {
  const client = createAlchemyPublicRpcClient({
    chain,
    transport,
  });
  try {
    let userOp = await client.getUserOperationByHash(uoHash);
    console.log("User Operation: ", userOp);
  } catch (error) {
    console.error("Error processing UserOperation:", error);
  }
}

Make sure that your environment is set with the correct ALCHEMY_API_KEY and PRIVATE_KEY. These examples assume familiarity with ERC-4337 and proper configuration of the EntryPoint contract (entryPoint07Address).

Bundler API - Using SDK

Manage UserOperations with @account-kit/infra