> For the complete documentation index, see [llms.txt](https://fusionauth.io/docs/llms.txt)

# Lambda API | FusionAuth Docs

Learn about the APIs for creating, retrieving, updating and deleting lambdas.

# Lambda API

[Edit on GitHub](https://github.com/FusionAuth/fusionauth-site/blob/main/astro/src/content/docs/apis/lambdas/index.mdx)

[View Markdown](https://fusionauth.io/docs/apis/lambdas.md)

Available since `1.6.0`

Lambdas are user defined JavaScript functions that may be executed at runtime to perform various functions. Lambdas may be used to customize the claims returned in a JWT, reconcile a SAML v2 response or an OpenID Connect response when using these external identity providers.

Use the following APIs to manage Lambdas:

| Operation | Method | Endpoint |
| --- | --- | --- |
| [Create a Lambda](https://fusionauth.io/docs/apis/lambdas/create-a-lambda.md) | `POST` | `/api/lambda`  
`/api/lambda/{lambdaId}` |
| [Retrieve a Lambda](https://fusionauth.io/docs/apis/lambdas/retrieve-a-lambda.md) | `GET` | `/api/lambda`  
`/api/lambda?type={type}`  
`/api/lambda/{lambdaId}` |
| [Search for Lambdas](https://fusionauth.io/docs/apis/lambdas/search-for-lambdas.md) | `GET`  
`POST` | `/api/lambda/search?body={body}&name={name}&type={type}`  
`/api/lambda/search` |
| [Update a Lambda](https://fusionauth.io/docs/apis/lambdas/update-a-lambda.md) | `PUT` | `/api/lambda/{lambdaId}` |
| [Delete a Lambda](https://fusionauth.io/docs/apis/lambdas/delete-a-lambda.md) | `DELETE` | `/api/lambda/{lambdaId}` |