paymasterService Capability

A capability for apps to communicate with wallets about ERC-4337 paymaster web services.

Defined in ERC-7677.

Specification

App

If you want to sponsor your users' transactions, you can do so by passing a paymaster service URL along with wallet_sendCalls requests. Specifically, you will need to include a paymasterService object in capabilities. This object should have a single field, url, that points to your paymaster service.

It's important to note that the URL you provide must be ERC-7677-compliant. If a connected wallet supports paymaster services, it will communicate with the provided URL according to ERC-7677 to get paymaster-related user operation fields.

Example

provider.request({
  method: 'wallet_sendCalls',
  params: [{
    version: '1.0',
    chainId: '0x01',
    from: '0xd46e8dd67c5d32be8058bb8eb970870f07244567',
    calls: [
      {
        to: '0xd46e8dd67c5d32be8058bb8eb970870f07244567',
        value: '0x9184e72a',
        data: '0xd46e8dd67c5d32be8d46e8dd67c5d32be8058bb8eb970870f072445675058bb8eb970870f072445675'
      },
      {
        to: '0xd46e8dd67c5d32be8058bb8eb970870f07244567',
        value: '0x182183',
        data: '0xfbadbaf01'
      }
    ],
    capabilities: {
      paymasterService: {
        url: 'https://your-paymaster-service.xyz'
      }
    }
  }]
})

Wallet

To support the paymasterService capability, a wallet must do two things:

1. Indicate it can leverage paymaster services as part of its response to a wallet_getCapabilities request.
2. Communicate with the paymaster service according to ERC-7677 if a wallet_sendCalls request includes a paymaster service URL.

wallet_getCapabilities Behavior

If a wallet is able to make use of paymaster web services to sponsor a user's call bundle, it should indicate this as part of its response to a wallet_getCapabilities request. Specifically, for each chain the wallet can use paymaster services on, its response to wallet_getCapabilities should include a paymasterService object. This object shoud have a single field, supported, set to true.

Example

provider.request({
  method: 'wallet_getCapabilities',
  params: ['0xd46e8dd67c5d32be8058bb8eb970870f07244567']
})
{
 
  "0x2105": {
 
    paymasterService: {
 
      supported: true,
 
    }
 
  }
 
}

wallet_sendCalls Behavior

As outlined above, apps that wish to sponsor their users' transactions will provide a paymasterService capability object in their wallet_sendCalls requests. This paymasterService capability will have a url field, which indicates where wallets should send ERC-7677 paymaster RPC requests to.

Wallets will need to make two RPC requests to this URL:

1. pm_getPaymasterStubData
   • Returns dummy paymaster values to be used during gas estimation.
2. pm_getPaymasterData
   • Returns real paymaster values to be used during user operation submission.