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

# Deployments and domains

> How ProductOS ships your app: sandbox previews while you build, then a self-checking deploy to a live URL or your own custom domain.

Your app is visible from the first file written and shippable whenever you decide it is ready. Two mechanisms make that work: sandbox previews during development, and the Deploy Agent when you want to go live.

## Live previews while you build

Every project runs in an isolated cloud sandbox with a live preview URL. As agents write files, install dependencies, and run builds, the preview updates, so you review real behavior rather than descriptions of it. Previews are for development; they are not your production URL.

## Deploying

Deploy is an on-demand action, not a pipeline stage: trigger it whenever you want, as often as you want. When you do, the Deploy Agent runs a sequence designed to ship a working app, not just push files:

<Steps>
  <Step title="Check recent deploys">
    The agent first checks whether a recent deploy already covers the current state, avoiding redundant work.
  </Step>

  <Step title="Preflight build">
    It builds the project before anything ships. Problems surface here, not in production.
  </Step>

  <Step title="Push to GitHub">
    The code is pushed to your own GitHub repository, so every deploy corresponds to a commit you can inspect. See [Code ownership](/platform/code-ownership).
  </Step>

  <Step title="Deploy to Vercel">
    The app deploys to Vercel and comes up at its live URL.
  </Step>
</Steps>

If the build or deploy fails, the agent does not just report the error: it attempts to fix the problem itself, with up to 3 self-fix iterations before it hands the issue back to you.

<Tip>
  Run [QA](/build/qa) before deploying. The QA Agent tests your app in a real headless browser and returns a pass, partial, or fail verdict, and a fail can chain into an auto-fix run.
</Tip>

## Domains

Deployed apps ship to one of two places:

| Option             | URL                           | Availability  |
| ------------------ | ----------------------------- | ------------- |
| Platform subdomain | `{slug}.product-os.app`       | All plans     |
| Custom domain      | Your own domain, no watermark | Pro and above |

The platform subdomain is the default: every deployed project gets a `{slug}.product-os.app` address with no setup. On Pro and above you can attach your own custom domain, and the watermark is removed. See [Plans and credits](/getting-started/plans-and-credits) for plan details.

## Where this runs

All ProductOS deployments target Vercel, and your code always flows through your own GitHub repo on the way there. That means no proprietary hosting layer: if you later want to deploy the same repo yourself, through your own Vercel account or any other host, nothing stands in the way.

## Related pages

* [Deploy Agent](/agents/deploy): the agent behind the deploy action
* [Sandboxes](/code/sandboxes): how the development environment works
* [Security and data](/platform/security-and-data): isolation and data handling