Move custom domains off Vercel
Fern Docs sites are now prebuilt as static pages and served from the edge, so pages load faster and a publish no longer slows your site down. Custom domains that still point to Vercel, Fern’s previous hosting, must point to cname.ferndocs.com by December 1, 2026. You can now make the switch from the Dashboard, and your docs stay live on the current setup until you change the DNS record.
fern generate --docs(including--preview) warns when acustom-domainstill points to Vercel and lists each affected domain.- From December 1, 2026, the warning becomes an error and publishing to that domain fails.
- Subpath domains and domains behind a reverse proxy or your own CDN aren’t affected.
To switch, go to your docs site in the Dashboard and select Make the switch.