> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kraken.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Challenge

> Request a challenge for user authentication handshake

<div className="api-banner">
  <span className="api-protocol ws">WSS</span>
  <span className="api-detail">futures.kraken.com/ws/v1</span>
  <span className="api-tag">challenge</span>
</div>

This request returns a challenge to be used in handshake for user authentication.

***

## Request

<ResponseField name="event" type="string" required>
  The request event type.
</ResponseField>

<ResponseField name="api_key" type="string" required>
  The user API key.
</ResponseField>

<CodeGroup>
  ```json Example theme={null}
  {
    "event": "challenge",
    "api_key": "CMl2SeSn09Tz+2tWuzPfdaJdsahq6qv5UaexXuQ3SnahDQU/gO3aT+"
  }
  ```
</CodeGroup>

***

## Response Success

<ResponseField name="event" type="string">
  Value: `challenge`
</ResponseField>

<ResponseField name="message" type="string">
  The message that user will have to sign for authentication reasons.
</ResponseField>

<CodeGroup>
  ```json Example theme={null}
  {
    "event": "challenge",
    "message": "226aee50-88fc-4618-a42a-34f7709570b2"
  }
  ```
</CodeGroup>

***

## Response Error

<ResponseField name="event" type="string">
  Value: `error`
</ResponseField>

<ResponseField name="message" type="string">
  An error message. Value: `Json Error`
</ResponseField>

<CodeGroup>
  ```json Example theme={null}
  {
    "event": "error",
    "message": "Json Error"
  }
  ```
</CodeGroup>