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

# Choose a domain

> Serve your site on a subdomain like blog.acme.com or under a path of your existing website like acme.com/blog.

Every site starts on a free Notra address, `https://<address>.notra.site`, which you choose when you create the site. To use your own domain, open the site's **Domains** page and click **Add domain**, which offers two setups:

| | Subdomain | Path on your website |
| - | - | - |
| Example | `blog.acme.com/` | `acme.com/blog` |
| What you change | DNS records at your DNS provider | A rewrite on the host that serves `acme.com` |
| Your website | Not touched | Keeps serving everything else |
| Search engines | Treat it as a separate host | Count it toward `acme.com` |
| Set up in | 5 minutes, plus DNS propagation | 10 minutes, plus a deploy of your website |
| Guide | [Subdomain](/docs/sites/domains/subdomain) | [Path on your website](/docs/sites/domains/subpath) |

Pick a **subdomain** when you want the simplest setup, and a **path** when you want your blog to build on the authority of your main domain or when your website already links to `/blog`.

<Tip>
  In the **Add domain** dialog, type `blog.acme.com` for a subdomain or `acme.com/blog` for a path, and Notra picks the matching setup. Use **Keep my website and forward paths instead** or **Point the whole domain to Notra instead** to switch.
</Tip>

## Section paths

A site has up to two sections, a blog and a changelog. You set their paths when you create the site and under **Settings → Content → Sections** rather than in `blog.json`, so a commit can never move your site somewhere nobody verified.

| Rule | Example |
| - | - |
| Up to three segments of lowercase letters, digits and dashes | `/blog`, `/updates`, `/changelog/notra` |
| One section can live at the root | blog at `/`, changelog at `/changelog` |
| The two paths can't be the same or nested inside each other | Notra rejects `/blog` and `/blog/changelog` |
| At least one section must be on | Turn a section off with its switch in **Settings**, or leave its path empty when you create the site |

The section paths are the same on every domain, so if the blog is at `/blog`, it's at `blog.acme.com/blog` and `acme.com/blog`. For a subdomain that shows the blog at its root, set the blog path to `/`.

Changing a path rebuilds the site, and the current version stays live until the new build is ready. If you serve the site through a rewrite, update the rewrite too.

## The primary address

When a domain passes its check, it becomes the site's **Primary** address, and Notra rebuilds the site so canonical URLs, feeds, sitemaps, `llms.txt` and social previews point to it. The previous version stays live during the rebuild.

* If you verify several domains, the one you checked last becomes primary.
* Your Notra address keeps working but tells search engines not to crawl it once a primary domain is set, and every page names the primary address as canonical, so a post is never indexed twice.
* Removing the primary domain moves the site back to its Notra address and rebuilds it.
* A domain can only be active on one site at a time.

Notra only ever serves previews on Notra addresses and never on your own domain. See [Previews](/docs/sites/previews).


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