# Users

A `User` resource represents a pair of API keys which are used to perform authenticated requests against the Finix API. When making authenticated requests via HTTP basic access authentication the ID of a `User` resource maps to the username, while the `password` corresponds to the password (i.e. secret key). <br/><br/> The password field for a `User` resource is only returned during the initial creation. Any following GET requests to the resource returns the `password` field as **null** for security purposes. <br/><br/> Related Guides: [Account Structure](/additional-resources/developers/resources-and-payment-flows/key-resources#account-structure)


## Create an Application User

 - [POST /applications/{application_id}/users](https://docs.finix.com/api/users/createapplicationuser.md): Creating an application user is the equivalent of provisioning API keys (i.e. credentials) for an .

> Each Application can have multiple  which allows each seller to have multiple API keys that can be independently enabled and disabled. Merchants only have read access to the API.

## List all Users

 - [GET /users](https://docs.finix.com/api/users/listusers.md): Retrieve a list of all .

For details on how to query endpoints using the available parameters, see Query Parameters.

## Fetch a User by ID

 - [GET /users/{user_id}](https://docs.finix.com/api/users/getuser.md): Retrieve a specific user with the ID of the .

## Update a User

 - [PUT /users/{user_id}](https://docs.finix.com/api/users/updateuser.md): Update a  with new tags or disable the  and their credentials.