Custom domain

After the first deploy you’ll have a host-generated URL like my-site.pages.dev, my-site.vercel.app, or my-site.netlify.app. Pointing your real domain at it is two changes — one on the host, one at your DNS provider.

Step 1 — Update Astro

In astro.config.mjs, set the production site:

astro.config.mjs

export default defineConfig({
  site: 'https://yourdomain.com',
  // …
});

And in src/config/site.ts:

url: "https://yourdomain.com",   // no trailing slash

These two values feed canonical URLs, the sitemap, OG tags, and any place the build needs to generate absolute URLs. Get them right before you submit your site to Google Search Console — incorrect canonicals are a pain to walk back.

Redeploy after changing.

Step 2 — Add the domain on your host

Pick the section that matches your host:

Cloudflare Pages

1. Project → Custom domains → Set up a custom domain.
2. Enter yourdomain.com.
3. Cloudflare auto-detects whether your domain is on Cloudflare DNS:
   • On Cloudflare DNS: it sets the CNAME automatically. Done.
   • Elsewhere: Cloudflare gives you a CNAME target like my-site.pages.dev. Add a CNAME at your DNS provider — see Step 3.
4. Add www.yourdomain.com too (separately) so both work.

Vercel

1. Project → Settings → Domains → Add.
2. Enter yourdomain.com.
3. Vercel asks: which version should be the canonical?
   • Apex (yourdomain.com) — A record points to Vercel’s IPs.
   • Subdomain (www.yourdomain.com) — CNAME to cname.vercel-dns.com.
4. Add the other variant too (with a 301 redirect to the canonical).

Netlify

1. Site → Domain management → Add custom domain.
2. Enter yourdomain.com.
3. Netlify gives you either an ALIAS/ANAME record (for the apex) or a CNAME (for subdomains).
4. Add both yourdomain.com and www.yourdomain.com; configure the redirect in Domain management → HTTPS settings.

Step 3 — Configure DNS

Where your DNS lives depends on where you bought the domain. Common providers:

• Cloudflare — dash.cloudflare.com → your domain → DNS.
• Namecheap — Domain List → Manage → Advanced DNS.
• Google Domains / Squarespace — DNS → Custom records.
• Porkbun — Manage → DNS records.

For most setups, you’ll add:

Apex (yourdomain.com)

Type	Name	Value
A	@	(Vercel/Netlify will give you specific IPs)
ALIAS	@	my-site.pages.dev (Cloudflare/Netlify supported; not all providers)

If your DNS provider supports ALIAS/ANAME, prefer that — it’s more flexible than A records.

Subdomain (www.yourdomain.com)

Type	Name	Value
CNAME	www	my-site.pages.dev

After saving, DNS propagation takes anywhere from 30 seconds to 24 hours. Most major providers update within 5 minutes.

Step 4 — Verify

dig yourdomain.com
dig www.yourdomain.com

# Or in a browser:
curl -I https://yourdomain.com

Look for a 200 and a header like cf-ray: (Cloudflare) or x-vercel-id: (Vercel) — that confirms requests are hitting your host.

SSL / HTTPS

Every host listed above issues a Let’s Encrypt certificate automatically. After DNS resolves, the cert lands within a few minutes. You don’t have to do anything.

If you see a “this site is not secure” warning after DNS resolves, wait 10 minutes. If it persists past 30 minutes:

• Cloudflare: check that SSL/TLS mode is set to Full (not Flexible).
• Vercel / Netlify: re-add the domain on the dashboard — that triggers a cert refresh.

www vs apex — which is canonical?

Pick one. The other should 301-redirect to it.

• www.yourdomain.com is canonical historically — easier with CNAMEs and works on every DNS provider.
• yourdomain.com (apex) is shorter and “modern” — requires ALIAS/ANAME or A records.

Both are fine. Just don’t run them as two separate sites — that splits Google’s PageRank.

Common gotchas

Site still serves the host-generated URL after DNS resolves

You also need to update siteConfig.url and astro.config.mjs site. The build bakes those in — without them, every canonical and OG URL still points to the old host URL.

Mixed-content warnings in the browser console

You linked to http:// somewhere instead of https://. Grep for http:// in your source and fix.

Domain works but redirects in a loop

Cloudflare Proxy + another CDN in front = redirect loop. Either:

• Set Cloudflare SSL to Full (strict), or
• Disable Cloudflare Proxy (“orange cloud” → “grey cloud”) on the record pointing to your host.

Test before you switch live

Before swapping DNS, add a host-file entry locally:

/etc/hosts (macOS / Linux)

192.0.2.42  yourdomain.com

(use the actual IP your host gave you). Now https://yourdomain.com resolves to your build for your machine only — perfect for testing canonical URLs, social-share previews, etc. Remove the line when you’re done.

What’s next

• Cloudflare Pages — full setup if you started from scratch.
• Configure → SEO — set OG tags using the new canonical.