> ## 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.

# Build your first app

> From a prompt to a working preview.

<Frame>
  <img src="https://cdn.youniverse.ai/blog-hero/docs/preview-devices.jpg" alt="The same app on desktop, tablet and phone" />
</Frame>

<Steps>
  <Step title="Start a New App">Open **AI Builder**, choose **New App** and describe what you want — or start from a category like Online store, Booking or Game.</Step>
  <Step title="Watch the first build">The first build of a new app is a flat **2,000 credits**, whatever its size. A progress overlay stays up until the fresh version is ready.</Step>
  <Step title="Refine in plain words">Ask for changes: *"make the pricing cards one column on phones"*. Check Desktop, Tablet and Mobile in the Preview tab.</Step>
  <Step title="Add keys when asked">**Settings → Setup & keys → Needs** lists anything a feature still requires.</Step>
  <Step title="Publish">Publishing is always free. See [Publish your app](/builder/publish).</Step>
</Steps>

## Questions are free

Questions, remarks and *"just asking"* messages are answered instantly at no cost. Only messages that order a change start the build agent. A small edit is typically around 180 credits.

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

## Spend less

* Name the page or file a change belongs to.
* One clear goal per message.
* Paste the exact error text from **Logs**.
* Use the visual editor for wording, colors and images — it's free.
* Roll back from **History** instead of asking the agent to undo.

## Common questions

<AccordionGroup>
  <Accordion title="Do questions cost credits?">
    No. Only messages that ask for a change start the build agent.
  </Accordion>

  <Accordion title="How much is a small edit?">
    Usually around 180 credits.
  </Accordion>

  <Accordion title="Is publishing free?">
    Yes, always.
  </Accordion>
</AccordionGroup>


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