# User Endpoints
As per [ERC-4337](https://eips.ethereum.org/EIPS/eip-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 ](/ids/chain-ids.md)page for details. |
| chainSymbol | String | Refer to the [Chain ID ](/ids/chain-ids.md)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](https://eips.ethereum.org/EIPS/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) |
{% tabs %}
{% tab title="Sample Request" %}
```url
https://api.expand.network/aa/getsignaturemessage?sender=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&chainId=1&callData=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
```
{% endtab %}
{% tab title="Sample Response" %}
```json
{
"status": 200,
"msg": "success",
"data": {
"messageToBeSigned": "0x4617338a3acd06271c356d52f8cfc260519e8e2115f0af41eb79b7ac13b1963c"
}
}
```
{% endtab %}
{% endtabs %}
### /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 ](/ids/chain-ids.md)page for details. |
| chainSymbol | String | Refer to the [Chain ID ](/ids/chain-ids.md)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](https://eips.ethereum.org/EIPS/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) |
{% tabs %}
{% tab title="Sample Request" %}
```url
https://api.expand.network/aa/getuserops?sender=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&chainId=1&callData=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
```
{% endtab %}
{% tab title="Sample Response" %}
```json
{
"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"
}
}
```
{% endtab %}
{% endtabs %}
---
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```
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```
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