Auth checked only in the UI in Vercel
criticalUpdated Oct 12, 2026
Deployment protection (a Vercel login in front of a preview) protects the preview URL. It does not protect your production API from the public internet.
Fix for Vercel
Deployment protection (a Vercel login in front of a preview) protects the preview URL. It does not protect your production API from the public internet. Do not treat a locked preview as production auth.
The five-minute check, the other platforms, and the agent prompt are on the full guide. More Vercel fixes are on the Vercel page.