Vercel Deployment Guide
Deployment Protection and Agent Access
Vercel deployments may have Deployment Protection enabled, which requires authentication to access preview deployments. This can block automated testing and agent access to preview URLs.
Identifying Protected Deployments
If you encounter a login page or authentication requirement when accessing a Vercel preview URL, the deployment has protection enabled. Signs include:
- Redirect to
vercel.com/loginor SSO login page - 401/403 errors when accessing the deployment
- Preview URLs that require Vercel team membership
Enabling Agent Access with Protection Bypass
To allow agents and automated systems to access protected deployments, users need to set up Protection Bypass for Automation:
- Navigate to Project Settings
- Go to the Vercel Dashboard - Select the project - Click on Settings → Deployment Protection
- Generate a Protection Bypass Secret
- Under "Protection Bypass for Automation", click Generate Secret - Copy the generated secret securely
- Using the Bypass Secret The secret can be used in two ways: As a Header:
curl -H "x-vercel-protection-bypass: <secret>" https://your-preview-url.vercel.appAs a Query Parameter:https://your-preview-url.vercel.app?x-vercel-protection-bypass=<secret> - For Browser-Based Testing
- Append ?x-vercel-protection-bypass=<secret> to the preview URL - The secret will be stored in a cookie for subsequent requests
Alternative: Disable Protection for Previews
If protection bypass is not suitable, users can disable protection for preview deployments:
- Go to Settings → Deployment Protection
- Set "Vercel Authentication" to Only Production Deployments or Disabled
Do NOT repeatedly attempt to access protected URLs without the bypass secret.
Environment Variables
Set environment variables in Vercel Dashboard under Settings → Environment Variables, or use the Vercel CLI:
vercel env add MY_SECRETAccess in your application:
const secret = process.env.MY_SECRET;Vercel CLI Commands
Common Vercel CLI commands:
# Login to Vercel
vercel login
# Deploy to preview
vercel
# Deploy to production
vercel --prod
# List deployments
vercel ls
# View deployment logs
vercel logs <deployment-url>
# Pull environment variables locally
vercel env pull