# Auth SDK

<figure><img src="/files/aLKFvLp7HQKVO4nsRAy0" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
**The Headless Auth SDK is intended to be used only with server-side apps to authenticate your website/app with your secure App Token. This token should be kept secret, and should not be made available to anyone on the client side for security reasons.**
{% endhint %}


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://api.circle.so/apis/headless/auth-sdk.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.