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Approving Paymaster in Axir Smart Account

Overview​

This guide explains how to approve different paymasters for gas fee payment in your Axir smart account.

Notes:

  • The Smart Contract Wallet needs to approve the AXRERC20 Paymaster to spend its fee tokens to be able to use AXR ERC20 Paymaster.
  • This first approve tx cannot be done with AXRERC20 Paymaster because of how pimlico bundlers behave currently , so either don't use paymasters or use AXRPaymaster for this first approve tx.

Prerequisites​

import { AxirCore } from "axr-erc4337-sdk";
import { ethers } from "ethers";

// Network-specific paymaster addresses
const PAYMASTERS = {
  sepolia: {
    pimlico: '0x000000000041F3aFe8892B48D88b6862efe0ec8d',
    axr: '0x45576D2958408B2736C7254369DC04A4EE130Ac4',
    erc20Token: '0xE61A8c5ccbd49d5a31958Cf59ddb4EA1914AF149'
  },
  baseSepolia: {
    pimlico: '0x00000000002E3A39aFEf1132214fEee5a55ce127',
    axr: '0x2ee7CbDDcb0774280B533894789a627921E1c6EA',
    erc20Token: '0x036CbD53842c5426634e7929541eC2318f3dCF7e'
  }
};

Paymaster Approval Implementation​

1. Approving AXR Paymaster​

const smartWallet = new AxirCore(
  PRIVATE_KEY,
  RPC_URL,
  BUNDLER_URL,
  BigInt(0),
  'sepolia'
);

// Approve AXR  Paymaster
await smartWallet.tokenApprove(
  PAYMASTERS.sepolia.erc20Token, // token address
  PAYMASTERS.sepolia.pimlico, // paymaster address
  ethers.parseEther('100'), // approval amount
  undefined, // additional data
  true, // use paymaster
  'AXRPaymaster' // paymaster type
);

2. Approving AXR ERC20 Paymaster​

// Approve AXR Paymaster
await smartWallet.tokenApprove(
  PAYMASTERS.sepolia.erc20Token,
  PAYMASTERS.sepolia.axr,
  ethers.parseEther('100'),
  undefined,
  true,
  'AXRERC20Paymaster'
);