Paymaster Endpoint

As per ERC-4337, Paymasters facilitate transaction sponsorship, allowing third-party-designed mechanisms to pay for transactions. Many of these mechanisms could be done by having the paymaster wrap a UserOperation with their own, but there are some important fundamental limitations to that approach:

• No possibility for “passive” paymasters (eg. that accept fees in some ERC-20 token at an exchange rate pulled from an on-chain DEX)

• Paymasters run the risk of getting griefed, as users could send ops that appear to pay the paymaster but then change their behavior after a block

Utilize the following APIs to get paymaster data and signature.

/getpaymasterdata

Get the paymaster data, that can be sent in the user operations.

GET https://api.expand.network/aa/getpaymasterdata

Query Parameters

Name	Type	Description
chainId	String	Refer to the Chain ID page for details.
chainSymbol	String	Refer to the Chain ID page for details.
sender*	String	On-chain wallet address.
rpc	String	Remote procedural call URL.
nonce	String	Anti-replay parameter.
initCode	String	The initCode of the account. (needed if and only if the account is not yet on-chain and needs to be created)
preVerificationGas	String	The amount of gas to pay for to compensate the bundler for pre-verification execution and calldata.
verificationGasLimit	String	The amount of gas to allocate for the verification step.
gasLimit	String	Maximum gas limit provided by the sender, for the transaction.
callGasLimit	String	The amount of gas to allocate the main execution call.
callData	String	Encoded data for executing the primary function call or operation within the user's transaction.
maxPriorityFeePerGas	String	Maximum priority fee per gas. (similar to EIP-1559 max_priority_fee_per_gas)
maxFeePerGas	String	The maximum fee per gas to pay for the execution of this operation. (similar to EIP-1559 max_fee_per_gas)
signature	String	Data passed into the account along with the nonce during the verification step.
paymasterAndData	String	Address of paymaster sponsoring the transaction, followed by extra data to send to the paymaster. (empty for self-sponsored transaction)
paymasterContractAddress*	String	Address of the contract from where, gas is to be paid.
mockValidAfter*	String	The UserOp is valid only after this time, to be sent in epoch time format.
mockValidUntil*	String	The UserOp is valid only up to this time, to be sent in epoch time format.

Sample Request

https://api.expand.network/aa/getpaymasterdata?sender=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&chainId=1&paymasterContractAddress=0xba60b04029be2bfd16d76e70290acfad3a8b582c&mockValidUntil=0x00000000deadbeef&mockValidAfter=0x0

Sample Response

{
    "status": 200,
    "msg": "success",
    "data": {
        "paymasterData": "0xba60b04029be2bfd16d76e70290acfad3a8b582c00000000000000000000000000000000000000000000000000000000deadbeef00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
        "hash": "0x2907ffb2f2320e35a041bd74235caed02f706e3ed4b2308f0a064a1f9e0aac67",
        "mockValidUntil": "0x00000000deadbeef",
        "mockValidAfter": "0x0"
    }
}