> ## Documentation Index
> Fetch the complete documentation index at: https://docs.youniverse.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# What is an app?

> The three layers every app is built from.

<Frame>
  <img src="https://cdn.youniverse.ai/blog-hero/docs/app-layers.jpg" alt="Stacked glass layers: database, logic and screens" />
</Frame>

Every app the AI Builder makes has three layers:

| Layer | What it is | Example |
| - | - | - |
| **Screens** | What people see and tap | Menu page, cart, sign-in form |
| **Logic** | The rules behind the screens | Calculate a total, send a receipt |
| **Data** | Where information is kept | Products, orders, users |

<Frame>
  <img src="https://cdn.youniverse.ai/blog-hero/docs/data.jpg" alt="Glass database beside a data table" />
</Frame>

You don't need to build these yourself — describe what you want and the builder handles all three. Knowing them helps you ask for changes clearly.

## Common questions

<AccordionGroup>
  <Accordion title="Do I need to code?">
    No. Describe what you want and the builder handles screens, logic and data.
  </Accordion>

  <Accordion title="Why learn the three layers?">
    It helps you ask for changes clearly.
  </Accordion>
</AccordionGroup>


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.