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RPC methods

This page has a reference to the list of available RPC methods that are common to all Paymaster API endpoints. For the list of available endpoints see the table here.

pm namespace​

These endpoints relate to a paymaster's off-chain component.

This methods sends a UserOperation to a paymaster for off-chain verification. If approved, it will return the paymasterAndData field as the result which can be appended to the UserOperation before signing.

If the paymaster rejects the UserOperation it does not return a result but a standard JSON-RPC error with the reason.

Parameters:

  • partial UserOperation: This essentially the UserOperation without the signature field. The final signature must include the returned paymasterAndData or it will fail validation.
  • entryPoint: The EntryPoint address the UserOperation is intended for.
  • chainId: The chainId the UserOperation is intended for.

Request​

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "pm_sponsorUserOperation",
  "params": [
    {
      sender, // address
      nonce, // uint256
      initCode, // bytes
      callData, // bytes
      callGasLimit, // uint256
      verificationGasLimit, // uint256
      preVerificationGas, // uint256
      maxFeePerGas, // uint256
      maxPriorityFeePerGas, // uint256
      paymasterAndData, // bytes
    }
  ]
}

Response (success)​

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x1234...5678" // valid paymasterAndData value
}

Response (error)​

{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "message": "Error reason here.",
    "code": -32601
  }
}

Supported EntryPoints​

This method is almost identical to what is specified in the ERC-4337 standard for eth_supportedEntryPoints except with the inclusion of a chainId param. It returns an array of the entryPoint addresses supported by the paymaster for the specified Network.

Ideally, apps can use this method to check if a Paymaster is currently online and ready to accept sponsorship requests.

Request​

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "pm_supportedEntryPoints",
  "params": [
      chainId // string
  ]
}

Response​

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": ["0x0F46c65C17AA6b4102046935F33301f0510B163A"]
}

Client SDK integration​

The eth-infinitism client SDK has a class component for integrating a generic PaymasterAPI. We recommend creating a new VerifyingPaymasterAPI class that extends PaymasterAPI to support the pm_sponsorUserOperation method. Refer to the examples repo to see how you can do this using TypeScript.