Legacy RPC Methods

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Legacy

This page references the methods for the legacy PAYG Paymaster API. This legacy API has been replaced in v0.6 and will be deprecated soon.

Endpoint

The v0.4 PAYG paymaster endpoint is https://app.stackup.sh/api/v2/paymaster/payg/API_KEY

pm namespace

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

Sponsor UserOperation

This method 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.

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "pm_sponsorUserOperation",
  "params": [
    // A partial UserOperation object.
    // This is essentially the UserOperation without the signature field.
    // The final signature for the UserOperation must include the returned paymasterAndData.
    {
      sender, // address
      nonce, // uint256
      initCode, // bytes
      callData, // bytes
      callGasLimit, // uint256
      verificationGasLimit, // uint256
      preVerificationGas, // uint256
      maxFeePerGas, // uint256
      maxPriorityFeePerGas, // uint256
      paymasterAndData, // bytes
    },
    // The EntryPoint address the UserOperation is intended for
    entryPoint
  ]
}

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

{
  "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.

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

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": ["0x0576a174D229E3cFA37253523E645A78A0C91B57"]
}

Client SDK integration

The eth-infinitism client SDK has a class component for integrating a generic PaymasterAPI. However, we recommend creating a new VerifyingPaymasterAPI class that extends PaymasterAPI to support the pm_sponsorUserOperation method. Please see this example VerifyingPaymasterAPI.