How to Pay Gas in ERC-20 Tokens | EIP-7702

Smart EOAs via EIP-7702

Offer the ability for users to pay gas in ERC-20s using any of the supported ERC-20 Tokens on Candide Paymaster.

1. Create a new app on the dashboard and copy the Paymaster RPC URL into your .env file.
2. Select an ERC-20 token to pay gas with and add its address to the .env file. We use CTT in this example.

index.ts

import {
  ...
  CandidePaymaster,
} from "abstractionkit";

const paymasterRPC = process.env.PAYMASTER_RPC as string;
const tokenAddress = process.env.TOKEN_ADDRESS as string;

const paymaster = new CandidePaymaster(paymasterRPC)

const tokensSupported = await paymaster.fetchSupportedERC20TokensAndPaymasterMetadata();
const tokenSelected = tokensSupported.tokens.find(
    token => token.address.toLocaleLowerCase() === tokenAddress.toLowerCase()
);

if (tokenSelected) {
    userOperation = await paymaster.createTokenPaymasterUserOperation(
        smartAccount, // = new Simple7702Account(eoaDelegator.address)
        userOperation,
        tokenSelected.address,
        bundlerUrl,
    )

    const cost = await paymaster.calculateUserOperationErc20TokenMaxGasCost(
        userOperation,
        tokenSelected.address
    )
    console.log("This useroperation may cost upto : " + cost + " wei in CTT token")
    console.log("Please fund the sender account: " + userOperation.sender +" with more than "+ cost + " wei CTT token")
}

.env

PAYMASTER_RPC=https://api.candide.dev/paymaster/$version/$network/$apikey
TOKEN_ADDRESS=0xFa5854FBf9964330d761961F46565AB7326e5a3b # CTT address on sepolia

info

Don't forget to fund the account with ERC-20s to pay for gas. We are using Candide Test Tokens (CTT) for this example. Request some on our Discord.