How-to: Deploy an ERC-4337 paymaster on Arc

import { ethers } from "ethers";

// Verify the EntryPoint v0.7 address for Arc testnet before use
const ENTRY_POINT_ADDRESS = "0x0000000071727De22E5E9d8BAf0edAc6f37da032";
const PAYMASTER_ADDRESS = "<your-paymaster-address>";

const ENTRY_POINT_ABI: string[] = [
  "function depositTo(address account) external payable",
  "function balanceOf(address account) external view returns (uint256)",
];

const provider = new ethers.JsonRpcProvider("https://rpc.testnet.arc.io");

// Open .env in your editor and add your deployer private key:
// DEPLOYER_PRIVATE_KEY=your-private-key
// Keep this key secure. It controls the paymaster's funding account.
const wallet = new ethers.Wallet(process.env.DEPLOYER_PRIVATE_KEY!, provider);

const entryPoint = new ethers.Contract(
  ENTRY_POINT_ADDRESS,
  ENTRY_POINT_ABI,
  wallet,
);

// Deposit 10 USDC: specify in wei (18-decimal native USDC units)
const depositAmount: bigint = 10n * 10n ** 18n;

const tx = await entryPoint.depositTo(PAYMASTER_ADDRESS, {
  value: depositAmount,
});
await tx.wait();

// Check the current deposit balance
// balanceOf returns 18-decimal native USDC units, not 6-decimal ERC-20 units
const balance: bigint = await entryPoint.balanceOf(PAYMASTER_ADDRESS);
const balanceUsdc: bigint = balance / 10n ** 18n;
console.log("Paymaster deposit balance (native wei):", balance.toString());
console.log("Paymaster deposit balance (USDC):", balanceUsdc.toString());