User Endpoints

As per ERC-4337, User Operations is a structure that describes a transaction to be sent on behalf of a user. To avoid confusion, it is not named “transaction”.

• Like a transaction, it contains “sender”, “to”, “calldata”, “maxFeePerGas”, “maxPriorityFee”, “signature”, “nonce”

• unlike a transaction, it contains several other fields, described below

• also, the “signature” field usage is not defined by the protocol, but by each account implementation

Utilize the following APIs to get the signature message & the user operation.

/getsignaturemessage

Get the signature message, which needs to be signed.

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

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)

Sample Request

https://api.expand.network/aa/getsignaturemessage?sender=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&chainId=1&callData=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

Sample Response

{
    "status": 200,
    "msg": "success",
    "data": {
        "messageToBeSigned": "0x4617338a3acd06271c356d52f8cfc260519e8e2115f0af41eb79b7ac13b1963c"
    }
}

/getuserops

Get the user operation, which can be signed and sent to the bundler.

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

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)

Sample Request

https://api.expand.network/aa/getuserops?sender=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&chainId=1&callData=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

Sample Response

{
    "status": 200,
    "msg": "success",
    "data": {
        "sender": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
        "nonce": "0",
        "initCode": "0x",
        "callData": "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",
        "callGasLimit": "260611",
        "gasLimit": "362451",
        "verificationGasLimit": "362451",
        "preVerificationGas": "53576",
        "maxFeePerGas": "29964445250",
        "maxPriorityFeePerGas": "100000000",
        "paymasterAndData": "0x",
        "signature": "0x"
    }
}