> For the complete documentation index, see [llms.txt](https://docs.sendstackhq.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sendstackhq.com/the-basics/authentication.md).

# Authentication

All requests to your CTRL business must be routed to the correct app and authenticated with an App ID and App Secret. 

The App ID, App Secret, and source must be provided with each request header as defined below: 

## Sample authentication

<mark style="color:blue;">`GET`</mark> `{baseUrl}/sample`

#### Headers

| Name                                                 | Type   | Description                      |
| ---------------------------------------------------- | ------ | -------------------------------- |
| app\_id<mark style="color:red;">\*</mark>            | String | 1234567                          |
| app\_secret<mark style="color:red;">\*</mark>        | String | MQ9VA2UMSZVW1QET7WLYFLEETFEGVA11 |
| x-sendstack-source<mark style="color:red;">\*</mark> | String | control.sendstack                |

{% tabs %}
{% tab title="200: OK Authenticated" %}

{% endtab %}

{% tab title="401: Unauthorized Unauthorized" %}

{% endtab %}
{% endtabs %}