How to Send a Gasless Transaction | EIP-7702

Smart EOAs via EIP-7702

Enable users to benefit from gasless transactions by offering publicly available gas policies set up by third parties on InstaGas like PoolTogether, AAVE, Unizen and many more. If no matching public gas policy is found for the user operation, you can fall back to a private gas policy of your own.

Definitions:

• Public Gas Policies: Gas sponsorships provided by Dapps and do not require a sponsorship policy ID.
• Private Gas Policies: Require a sponsorship policy ID and can be used by the wallet if no public gas policy matches the user operation.

Steps to Implement Gasless Transactions:

1. Create a new app on the dashboard and copy the Paymaster RPC URL into your .env file.
2. Optionally, set up a Private Gas Policy on the dashboard and copy its sponsorship policy ID into your .env file.

index.ts

import {
  CandidePaymaster,
} from "abstractionkit";

const paymasterRPC = process.env.PAYMASTER_RPC as string;
const paymaster: CandidePaymaster = new CandidePaymaster(paymasterRPC);
const sponsorshipPolicyId = process.env.SPONSORSHIP_POLICY_ID;

let paymasterUserOperation;
let sponsorMetadata;
try {
  // sponsor gas using public gas policies
  [paymasterUserOperation, sponsorMetadata] =
    await paymaster.createSponsorPaymasterUserOperation(
      userOperation,
      bundlerUrl,
    );
} catch (publicGasPolicyUnavailable) {
  try {
    // sponsor gas using a private gas policy
    [paymasterUserOperation, sponsorMetadata] =
      await paymaster.createSponsorPaymasterUserOperation(
        userOperation,
        bundlerUrl,
        sponsorshipPolicyId,
      );
  } catch (privateGasPolicyUnavailable) {
    // fallback to propose to the user the option to pay gas in erc-20 tokens
  } catch (erc20GasPaymentUnavalable) {
    // Last fallback to propose to the user the option to pay gas in native token
  }
}

userOperation = paymasterUserOperation;

.env

PAYMASTER_RPC=https://api.candide.dev/paymaster/$version/$network/$apikey
SPONSORSHIP_POLICY_ID=