> For the complete documentation index, see [llms.txt](https://docs.8select.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.8select.io/api/general/authentication.md).

# Authentication

{% hint style="info" %}
To obtain your API ID for use with the 8SELECT API, please speak to your account manager.
{% endhint %}

Your API ID is permanently linked to your 8SELECT account. It must be included in every call to the API as a `x-api-id` header to authorize your request:

```
POST /graphql
Host: https://api.8select.io
x-api-id: <Your API ID>
```