Custom Domains

1.Deploy the website first

A custom domain attaches to a function that already serves a website. Deploy the function so it has a live version, then it becomes selectable as a domain target. See Websites for how a function serves HTML.

• Only deployed functions in your workspace appear in the domain target picker.
• One domain serves one website; add more domains to point at other websites.

2.Add your domain

In Workspace Settings → Domains, choose Add domain, enter the hostname you own, and pick which website it should serve. hostfunc registers the hostname and returns the exact DNS records to add.

• Enter a bare hostname — www.example.com, no https:// and no path.
• A subdomain like www or app is the simplest to connect.

3.Add the DNS records at your registrar

Copy the CNAME (and any TXT validation records) into your registrar's DNS editor — Namecheap, GoDaddy, Cloudflare, etc. The Domains screen shows provider-specific hints next to each record.

• Subdomain: add a CNAME from your host (e.g. www) to the target shown (e.g. cname.hostfunc.app).
• TXT records prove you control the domain so the SSL certificate can be issued.
• Root/apex domains can't use a CNAME — use your registrar's ALIAS/ANAME or CNAME-flattening to the same target, or point www and add an apex redirect.

4.Wait for verification and SSL

The Domains screen polls automatically: it moves from “Add DNS records” to “Issuing SSL” to “Live”. DNS propagation and certificate issuance can take a few minutes (occasionally longer) — you can close the page and come back.

• “Add DNS records” — waiting for your records to be visible.
• “Issuing SSL” — records verified, certificate being provisioned.
• “Live” — your site is served at https://yourdomain with a valid certificate.

5.Receive email on your domain

Once a domain is live, the function's email trigger can use it: regenerate the inbound address on the function's Triggers page and it is issued on your domain (e.g. site-acme-x7q2w3e4@www.example.com). An Inbound email panel then appears on the Domains screen with the MX and TXT records to add.

• Add the MX/TXT rows exactly as shown (in Namecheap: Domain List → Manage → Advanced DNS). The MX record must have the lowest priority value on that name.
• The panel polls verification automatically; once it shows “Receiving”, mail to the generated address triggers your function.
• Inbound email DNS is separate from the website CNAME — removing one doesn't affect the other until the domain itself is removed.

6.Remove a domain

Removing a domain stops routing it, deletes the hostname from Cloudflare (and its inbound-email registration), and frees it so it can be claimed again. Your website keeps serving on its run.hostfunc.io URL.

7.Limits and validation

Guardrails that apply when adding domains.

• Up to 20 custom domains per workspace.
• Hostnames must be ASCII (a-z, digits, hyphens); internationalized/punycode (xn--) names aren't supported yet.
• hostfunc.io, hostfunc.app, and hostfunc.dev names are reserved.