# Sign In Blocks

## Overview

Authentication is the process by which your app’s users sign up or sign in to your app. It confirms the legitimacy of a user's identity before allowing them to interact with the application. 

Thunkable supports authentication through:

{% content-ref url="/pages/WIkJxydctAv4Z0IHKTHK" %}
[User Sign Up, Sign In, and Authentication with Firebase](/blocks/app-features/sign-in/sign-in.md)
{% endcontent-ref %}

{% content-ref url="/pages/afVi7mBt7fMkwXE5wLyw" %}
[User Sign Up, Sign In, and Authentication with Google](/blocks/app-features/sign-in/sign-in-1.md)
{% endcontent-ref %}

{% content-ref url="/pages/QQpFDowIjy05ldVe7kSx" %}
[User Sign Up, Sign In, and Authentication with Apple](/blocks/app-features/sign-in/user-sign-up-sign-in-and-authentication-with-apple.md)
{% endcontent-ref %}


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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://docs.thunkable.com/blocks/app-features/sign-in.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.