# Custom UI

You can build your own custom UI powered by the new Authentication Flow API. Here are some resources for getting started:

{% content-ref url="/pages/bh9jTI1HfOss0Ga6QOXo" %}
[Authentication Flow API](/customization/custom-ui/authentication-flow-api.md)
{% endcontent-ref %}

{% content-ref url="/pages/He7jrk5pGyIal720Wguq" %}
[Implement Authentication Flow API using PHP](/customization/custom-ui/implement-authentication-flow-api-using-php.md)
{% endcontent-ref %}

{% content-ref url="/pages/o7crbElU3llCeleh5K9w" %}
[Implement Authentication Flow API using Express](/customization/custom-ui/implement-authentication-flow-api-using-express.md)
{% endcontent-ref %}

{% content-ref url="/pages/riCnWMQbTVvEYPkPMMEg" %}
[Add Custom Login/Signup UI to Native Apps](/customization/custom-ui/add-custom-login-signup-ui-to-native-apps.md)
{% endcontent-ref %}


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# Agent Instructions: Querying This Documentation

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

```
GET https://docs.authgear.com/customization/custom-ui.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.