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ERC

Getting Started

There are three parties involved in the ERC-7677 flow: paymaster services, apps, and wallets.

  • Paymaster services implement ERC-7677 pm_ RPC methods.
  • Apps give wallets their paymaster service URLs. This is done using the paymasterService capability as part of a EIP-5792 wallet_sendCalls request.
  • Wallets communicate with paymaster services at the URL provided by apps, using the standardized RPC methods to get paymaster-related fields during user operation construction.

Here is a high-level flow of what this looks like:

erc-7677

Paymaster Services

For a paymaster service to be ERC-7677 compliant, it must implement support for the two pm_ RPC methods specified in the ERC.

  • pm_getPaymasterStubData

    • Returns stub values to be used in paymaster-related fields of an unsigned user operation for gas estimation.

  • pm_getPaymasterData

    • Returns values to be used in paymaster-related fields of a signed user operation.

See the reference section for details on how these should be implemented.

Apps

To start using ERC-7677 to sponsor your users' transactions, you'll need to do two things:

  1. Sign up with an ERC-7677-compliant paymaster service provider and get a paymaster service URL.
  2. Send transactions using the EIP-5792 wallet_sendCalls method with the paymasterService capability.

One note on paymaster service URLs: service providers typically give developers URLs that have API keys in them. More often than not, you'll want to keep these API keys secret.

As a result, we recommend setting up an endpoint on your app's backend that is ultimately responsible for communication with your chosen paymaster service provider. Check out the guide on sponsoring your users' transactions for more.

Once you've signed up with a paymaster service provider and set up your proxy, you're ready to use the wallet_sendCalls RPC method to start sponsoring your users' transactions. The easiest way to do this is to use Wagmi:

App.tsx
import { useWriteContracts } from 'wagmi/experimental'
import { parseAbi } from 'viem'
 
const abi = parseAbi([
  'function approve(address, uint256) returns (bool)',
  'function transferFrom(address, address, uint256) returns (bool)',
])
 
function App() {
  const { writeContracts } = useWriteContracts()
 
  return (
    <button
      onClick={() =>
        writeContracts({
          contracts: [
            {
              address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
              abi,
              functionName: 'approve',
              args: [
                '0xa5cc3c03994DB5b0d9A5eEdD10CabaB0813678AC', 
                100n
              ],
            },
            {
              address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
              abi,
              functionName: 'transferFrom',
              args: [
                '0xa5cc3c03994DB5b0d9A5eEdD10CabaB0813678AC',
                '0x0000000000000000000000000000000000000000',
                100n
              ],
            },
          ],
          capabilities: { 
            paymasterService: { 
              url: 'https://...' // Your ERC-7677-compliant paymaster service URL.
            } 
          } 
        })
      }
    >
      Send calls
    </button>
  )
}

See the Wagmi documentation for more.

Wallets

As a prerequisite, wallets will need to be EIP-5792-compliant to leverage ERC-7677. You can find more about adding EIP-5792 support to your wallet on this page.

Once your wallet is EIP-5792-compliant, it will need to do two things to support ERC-7677:

  1. Indicate it can support sponsoring transactions via paymaster services as part of its reponse to wallet_getCapabilities requests.
provider.request({
  method: 'wallet_getCapabilities',
  params: ['0xd46e8dd67c5d32be8058bb8eb970870f07244567']
})

{
 
  "0x2105": {
 
    paymasterService: {
 
      supported: true,
 
    }
 
  }
 
}
  1. Communicate with paymaster services at URLs provided by apps using the new pm_ RPC methods.

See the guide on constructing a user operation with ERC-7677 for more.