Setup Environment Variables Per Branch

---
description: Configure different env vars for dev, staging, and production
---

1. **Local Development (.env.local)**:
- Create .env.local for local overrides (never commit this).

# .env.local
   DATABASE_URL=postgresql://localhost:5432/mydb
   API_URL=http://localhost:3001
   NEXT_PUBLIC_APP_URL=http://localhost:3000

2. **Shared Defaults (.env)**:
- Create .env for defaults (commit this).

# .env
   NEXT_PUBLIC_APP_NAME=MyApp
   NEXT_PUBLIC_MAX_UPLOAD_SIZE=5242880

3. **Vercel Environment Setup**:
- In Vercel Dashboard → Project → Settings → Environment Variables.
- Add variables for each environment:
- **Production**: main branch
- **Preview**: All other branches
- **Development**: Local only

4. **Access Branch-Specific Vars**:
- Vercel automatically injects VERCEL_ENV.

const apiUrl = process.env.VERCEL_ENV === 'production'
     ? 'https://api.myapp.com'
     : 'https://staging-api.myapp.com';

5. **GitHub Actions Setup**:
- Use secrets for CI/CD.

# .github/workflows/test.yml
   env:
     DATABASE_URL: ${{ secrets.DATABASE_URL }}
     API_KEY: ${{ secrets.API_KEY }}

6. **Pro Tips**:
- Prefix public vars with NEXT_PUBLIC_ for client-side access.
- Use .env.example as a template (commit).
- Never log environment variables in production.
- Use Vercel CLI to pull env vars: vercel env pull .env.local.