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 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.

If you would like to see full example, you can reference it here.

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/public/v3/sepolia
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.