> For the complete documentation index, see [llms.txt](https://docs.riff.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.riff.ai/reference/app-builder/preview.md).

# Preview

Preview is the default tab when you open an app in the App builder. It shows your app running live — you can interact with it exactly as your users will, and any change the Riff agent makes appears instantly without you needing to refresh.

## What you see

A full-height frame showing your app in its current state. While it connects you'll see the Riff loading screen briefly. Once ready, the app is fully interactive.

<div data-with-frame="true"><figure><img src="/files/t2HeyY8H05lYO2u3GjA5" alt=""><figcaption></figcaption></figure></div>

## How to use it

**Test as a user would.** Click buttons, fill in forms, navigate between pages. If something looks wrong, you've caught it before your team or customers see it.

**Changes appear immediately.** The Riff agent's edits hot-reload into Preview. You don't need to save or refresh — what you see is always current.

## Notes

Preview shows the **development version** of your app — not the deployed (production) version. Deploying is a separate step. See [Deploy](/reference/app-builder/deploy.md).


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