> ## Documentation Index > Fetch the complete documentation index at: https://docs.lucid.foundation/llms.txt > Use this file to discover all available pages before exploring further. # Paymaster SDK > ERC-4337 gas sponsorship — sponsor transactions, estimate fees, check rates # Paymaster SDK ERC-4337 gas sponsorship — sponsor transactions, estimate fees, check rates ## Operations | Method | Description | | ----------------------- | ----------------------------- | | `lucidSponsorUserOp` | Sponsor a UserOp with \$LUCID | | `lucidGetPaymasterRate` | Get LUCID/ETH exchange rate | | `lucidEstimateGasLucid` | Estimate gas cost in \$LUCID | ## Generated Reference ### Overview ERC-4337 gas sponsorship — sponsor transactions, estimate fees, check rates #### Available Operations * [lucidSponsorUserOp](#lucidsponsoruserop) - Sponsor a UserOp with \$LUCID * [lucidGetPaymasterRate](#lucidgetpaymasterrate) - Get LUCID/ETH exchange rate * [lucidEstimateGasLucid](#lucidestimategaslucid) - Estimate gas cost in \$LUCID ### lucidSponsorUserOp Sponsor an ERC-4337 UserOperation by paying the gas cost in LUCID tokens. The paymaster signs the UserOp and deducts LUCID from the sender's balance at the current exchange rate. #### Example Usage ```typescript theme={null} import { RaijinLabsLucidAi } from "raijin-labs-lucid-ai"; const raijinLabsLucidAi = new RaijinLabsLucidAi(); async function run() { const result = await raijinLabsLucidAi.paymaster.lucidSponsorUserOp({ chainId: "", userOp: {}, }); console.log(result); } run(); ``` #### Standalone function The standalone function version of this method: ```typescript theme={null} import { RaijinLabsLucidAiCore } from "raijin-labs-lucid-ai/core.js"; import { paymasterLucidSponsorUserOp } from "raijin-labs-lucid-ai/funcs/paymasterLucidSponsorUserOp.js"; // Use `RaijinLabsLucidAiCore` for best tree-shaking performance. // You can create one instance of it to use across an application. const raijinLabsLucidAi = new RaijinLabsLucidAiCore(); async function run() { const res = await paymasterLucidSponsorUserOp(raijinLabsLucidAi, { chainId: "", userOp: {}, }); if (res.ok) { const { value: result } = res; console.log(result); } else { console.log("paymasterLucidSponsorUserOp failed:", res.error); } } run(); ``` #### Parameters | Parameter | Type | Required | Description | | ---------------------- | --------------------------------------------------------------------------------------------------------------------------------- | -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | `request` | [models.SponsorUserOpRequest](https://github.com/lucid-fdn/lucid-ai-sdk/blob/main/typescript/docs/models/sponsoruseroprequest.md) | :heavy\_check\_mark: | The request object to use for the request. | | `options` | RequestOptions | :heavy\_minus\_sign: | Used to set various options for making HTTP requests. | | `options.fetchOptions` | [RequestInit](https://developer.mozilla.org/en-US/docs/Web/API/Request/Request#options) | :heavy\_minus\_sign: | Options that are passed to the underlying HTTP request. This can be used to inject extra headers for examples. All `Request` options, except `method` and `body`, are allowed. | | `options.retries` | [RetryConfig](https://github.com/lucid-fdn/lucid-ai-sdk/blob/main/typescript/docs/lib/utils/retryconfig.md) | :heavy\_minus\_sign: | Enables retrying HTTP requests under certain failure conditions. | #### Response **Promise\<[models.SuccessResponse](https://github.com/lucid-fdn/lucid-ai-sdk/blob/main/typescript/docs/models/successresponse.md)>** #### Errors | Error Type | Status Code | Content Type | | ------------------------------------ | ----------- | ---------------- | | errors.ErrorResponse | 400 | application/json | | errors.ErrorResponse | 500 | application/json | | errors.RaijinLabsLucidAiDefaultError | 4XX, 5XX | \*/\* | ### lucidGetPaymasterRate Retrieve the current LUCID-per-ETH exchange rate used for gas sponsoring on a specific EVM chain. The rate determines how much LUCID is charged per gas unit. #### Example Usage ```typescript theme={null} import { RaijinLabsLucidAi } from "raijin-labs-lucid-ai"; const raijinLabsLucidAi = new RaijinLabsLucidAi(); async function run() { const result = await raijinLabsLucidAi.paymaster.lucidGetPaymasterRate({ chainId: "", }); console.log(result); } run(); ``` #### Standalone function The standalone function version of this method: ```typescript theme={null} import { RaijinLabsLucidAiCore } from "raijin-labs-lucid-ai/core.js"; import { paymasterLucidGetPaymasterRate } from "raijin-labs-lucid-ai/funcs/paymasterLucidGetPaymasterRate.js"; // Use `RaijinLabsLucidAiCore` for best tree-shaking performance. // You can create one instance of it to use across an application. const raijinLabsLucidAi = new RaijinLabsLucidAiCore(); async function run() { const res = await paymasterLucidGetPaymasterRate(raijinLabsLucidAi, { chainId: "", }); if (res.ok) { const { value: result } = res; console.log(result); } else { console.log("paymasterLucidGetPaymasterRate failed:", res.error); } } run(); ``` #### Parameters | Parameter | Type | Required | Description | | ---------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | `request` | [operations.LucidGetPaymasterRateRequest](https://github.com/lucid-fdn/lucid-ai-sdk/blob/main/typescript/docs/models/operations/lucidgetpaymasterraterequest.md) | :heavy\_check\_mark: | The request object to use for the request. | | `options` | RequestOptions | :heavy\_minus\_sign: | Used to set various options for making HTTP requests. | | `options.fetchOptions` | [RequestInit](https://developer.mozilla.org/en-US/docs/Web/API/Request/Request#options) | :heavy\_minus\_sign: | Options that are passed to the underlying HTTP request. This can be used to inject extra headers for examples. All `Request` options, except `method` and `body`, are allowed. | | `options.retries` | [RetryConfig](https://github.com/lucid-fdn/lucid-ai-sdk/blob/main/typescript/docs/lib/utils/retryconfig.md) | :heavy\_minus\_sign: | Enables retrying HTTP requests under certain failure conditions. | #### Response **Promise\<[models.PaymasterRateResponse](https://github.com/lucid-fdn/lucid-ai-sdk/blob/main/typescript/docs/models/paymasterrateresponse.md)>** #### Errors | Error Type | Status Code | Content Type | | ------------------------------------ | ----------- | ---------------- | | errors.ErrorResponse | 500 | application/json | | errors.RaijinLabsLucidAiDefaultError | 4XX, 5XX | \*/\* | ### lucidEstimateGasLucid Estimate the LUCID token cost for a UserOperation before submitting it. Returns the estimated gas in ETH and the equivalent LUCID amount at the current exchange rate. #### Example Usage ```typescript theme={null} import { RaijinLabsLucidAi } from "raijin-labs-lucid-ai"; const raijinLabsLucidAi = new RaijinLabsLucidAi(); async function run() { const result = await raijinLabsLucidAi.paymaster.lucidEstimateGasLucid({ chainId: "", userOp: {}, }); console.log(result); } run(); ``` #### Standalone function The standalone function version of this method: ```typescript theme={null} import { RaijinLabsLucidAiCore } from "raijin-labs-lucid-ai/core.js"; import { paymasterLucidEstimateGasLucid } from "raijin-labs-lucid-ai/funcs/paymasterLucidEstimateGasLucid.js"; // Use `RaijinLabsLucidAiCore` for best tree-shaking performance. // You can create one instance of it to use across an application. const raijinLabsLucidAi = new RaijinLabsLucidAiCore(); async function run() { const res = await paymasterLucidEstimateGasLucid(raijinLabsLucidAi, { chainId: "", userOp: {}, }); if (res.ok) { const { value: result } = res; console.log(result); } else { console.log("paymasterLucidEstimateGasLucid failed:", res.error); } } run(); ``` #### Parameters | Parameter | Type | Required | Description | | ---------------------- | ----------------------------------------------------------------------------------------------------------------------------- | -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | `request` | [models.EstimateGasRequest](https://github.com/lucid-fdn/lucid-ai-sdk/blob/main/typescript/docs/models/estimategasrequest.md) | :heavy\_check\_mark: | The request object to use for the request. | | `options` | RequestOptions | :heavy\_minus\_sign: | Used to set various options for making HTTP requests. | | `options.fetchOptions` | [RequestInit](https://developer.mozilla.org/en-US/docs/Web/API/Request/Request#options) | :heavy\_minus\_sign: | Options that are passed to the underlying HTTP request. This can be used to inject extra headers for examples. All `Request` options, except `method` and `body`, are allowed. | | `options.retries` | [RetryConfig](https://github.com/lucid-fdn/lucid-ai-sdk/blob/main/typescript/docs/lib/utils/retryconfig.md) | :heavy\_minus\_sign: | Enables retrying HTTP requests under certain failure conditions. | #### Response **Promise\<[models.SuccessResponse](https://github.com/lucid-fdn/lucid-ai-sdk/blob/main/typescript/docs/models/successresponse.md)>** #### Errors | Error Type | Status Code | Content Type | | ------------------------------------ | ----------- | ---------------- | | errors.ErrorResponse | 400 | application/json | | errors.ErrorResponse | 500 | application/json | | errors.RaijinLabsLucidAiDefaultError | 4XX, 5XX | \*/\* |