What Is Vercel?
A cloud platform for deploying frontend frameworks and serverless functions, optimized for Next.js. Vercel provides automatic HTTPS, edge network deployment, preview environments, and serverless API routes. It is the most popular deployment target for AI-generated Next.js applications.
Security Risks
Vercel provides solid infrastructure security, but application-level risks remain:
- Environment variable exposure: Variables may leak through API responses or client bundles
- Preview deployment access: Preview URLs are public by default
- Serverless function security: API routes need explicit security controls
- Edge middleware limitations: Some security checks cannot run at the edge
- Build log exposure: Build logs may contain secrets if not properly managed
- Third-party integrations: Vercel integrations may have broad access to your project
Security Checklist
- Use Vercel environment variables (not hardcoded values) for all secrets
- Prefix client-side variables with NEXT_PUBLIC_ only when truly needed
- Enable Vercel Deployment Protection for preview environments
- Add security headers via vercel.json or next.config.js
- Implement authentication middleware for protected API routes
- Enable Vercel Web Application Firewall (if available on your plan)
- Configure proper CORS in API routes
- Review build logs for accidental secret exposure
- Set up Vercel Audit Log monitoring for team deployments
- Use Vercel Edge Middleware for rate limiting and geoblocking
Frequently Asked Questions
Does Vercel handle security automatically?
Vercel provides infrastructure security (automatic HTTPS, DDoS protection, edge network) but application security is your responsibility. You must add authentication, authorization, input validation, security headers, and access control to your application code.
How do I add security headers on Vercel?
Add headers in vercel.json or next.config.js: Content-Security-Policy, X-Frame-Options, Strict-Transport-Security, X-Content-Type-Options. Vercel respects these configurations and applies them to all responses. Use securityheaders.com to verify.
Are Vercel preview deployments secure?
Preview deployments are public by default – anyone with the URL can access them. Enable Vercel Deployment Protection to require authentication for preview URLs. Never connect preview deployments to production databases or services with real data.