How to Secure Your Vercel App
Last updated: January 12, 2026
Vercel handles infrastructure security, but application configuration is your responsibility. This guide covers securing your Vercel deployments and Next.js applications.
Step-by-Step Security Guide
1. Configure Environment Variables Properly
Add secrets in Vercel Dashboard, not in code. Scope variables to the correct environment (Production, Preview, Development).
2. Understand NEXT_PUBLIC_ Prefix
Variables with NEXT_PUBLIC_ are exposed to the browser. Never use this prefix for secrets.
# Server-only (safe)
DATABASE_URL=...
# Exposed to browser (public only)
NEXT_PUBLIC_API_URL=...3. Add Security Headers
Configure CSP, HSTS, and other security headers in next.config.js or vercel.json.
// next.config.js
headers: async () => [
{
source: '/(.*)',
headers: [
{ key: 'X-Frame-Options', value: 'DENY' },
{ key: 'X-Content-Type-Options', value: 'nosniff' },
],
},
]4. Protect Preview Deployments
Enable Deployment Protection to prevent unauthorized access to preview URLs.
5. Secure API Routes
Validate authentication and authorization in every API route and Server Action.
6. Run Security Scan
Use VAS to verify your deployment is secure before going live.
Common Security Mistakes
Avoid these common Vercel security pitfalls:
Recommended Security Tools
Use these tools to maintain security throughout development:
Ready to Secure Your App?
Security is an ongoing process, not a one-time checklist. After implementing these steps, use VAS to verify your Vercel app is secure before launch, and consider regular scans as you add new features.
Frequently Asked Questions
Are Vercel environment variables secure?
Yes, Vercel encrypts environment variables at rest and in transit. They're only exposed to your build and runtime. Just don't use NEXT_PUBLIC_ prefix for secrets.
How do I protect preview deployments?
Enable Deployment Protection in Project Settings. You can require Vercel authentication, password, or trusted IPs. This prevents unreleased features from being publicly accessible.