Bind a Custom Domain

After deploying, you need to point your own domain at the deployment platform so that email tracking links use your own domain.

DNS flexibility across the four platforms:

Platform	DNS requirement	Connection method
Cloudflare Workers	Entire zone must be hosted on CF	NS-level
Vercel	Any DNS provider	CNAME
Netlify	Any DNS provider	CNAME
Deno Deploy	Any DNS provider	CNAME

---

Cloudflare Worker

Prerequisite: your domain is already hosted on Cloudflare (DNS at Cloudflare).

Option A: Workers Routes (recommended — full subdomain takeover)

Best for: dedicating a subdomain (e.g., track.yourdomain.com) to tracking.

1. Open Cloudflare Dashboard → select your domain
2. Left sidebar DNS → Records → Add record
   • Type: AAAA
   • Name: track (or any subdomain you want)
   • IPv6 address: 100:: (placeholder, Worker handles all requests)
   • Proxy status: Proxied (orange cloud must be on)
3. Left sidebar Workers Routes → Add route
   • Route: track.yourdomain.com/*
   • Worker: select the just-deployed email-track-domain
4. Takes effect within minutes. Visit https://track.yourdomain.com/r/test to verify it reaches your backend.

Option B: Worker Custom Domain (simpler)

Best for: binding a Workers project directly to a domain (Cloudflare handles DNS and SSL automatically).

1. Open Workers Dashboard → select email-track-domain Worker
2. Settings → Triggers → Custom Domains → Add Custom Domain
3. Enter track.yourdomain.com, confirm
4. Cloudflare auto-creates DNS records and issues an SSL certificate

Difference: Option A is flexible (can route specific paths), Option B binds the whole domain (simpler). Most users should pick B.

---

Vercel

1. Open Vercel Dashboard → select project → Settings → Domains
2. Enter track.yourdomain.com, Add
3. Vercel will show the DNS record you need to add at your DNS provider, similar to:

   Type: CNAME
   Name: track
   Value: cname.vercel-dns.com

4. After adding DNS, wait a few minutes for Vercel to auto-issue the SSL certificate

---

Netlify

1. Open Netlify Dashboard → select site → Domain management → Custom domains → Add a domain
2. Enter track.yourdomain.com → Verify → Yes, add domain
3. Netlify shows the DNS records to add at your DNS provider:

   Type: CNAME
   Name: track
   Value: <your-site>.netlify.app

4. Wait for SSL to be issued (minutes to 24 hours)

---

Deno Deploy

1. Open dash.deno.com → select project → Settings → Domains → Add Domain
2. Enter track.yourdomain.com, Deno Deploy gives two records:

   Type: A      Name: track  Value: <your-IPv4>   (example, use the actual value)
   Type: AAAA   Name: track  Value: ...           (IPv6)

   Or use CNAME:

   Type: CNAME  Name: track  Value: <project>.deno.dev

3. Add the DNS records, then return to Deno Deploy and click Verify
4. SSL is issued automatically

---

Verification

After deployment + binding, visit in your browser:

URL	Expected behavior
https://track.yourdomain.com/	302 redirect to google.com (root not in allowlist)
https://track.yourdomain.com/test.php	302 redirect to google.com (blocked extension)
https://track.yourdomain.com/r/abc123	Forwarded to your backend (allowed path)
https://track.yourdomain.com/favicon.ico	Forwarded to your backend (allowed root file)

If the third one returns 502 "Backend fetch failed", BACKEND_HOST is misconfigured or the backend is unreachable.

---

Using in emails

Replace all tracking links in your emails that pointed to cf-track.laifa.xin with track.yourdomain.com. For example:

Old: http://cf-track.laifa.xin/r/abc123
New: https://track.yourdomain.com/r/abc123

Open/click statistics still flow to your original backend, but recipients see your own domain — more professional, and improves your anti-spam score.