This ensures new developers can get started immediately without hunting down configuration values from team members.
Next.js provides powerful built-in support for environment variables with a sophisticated file-loading system. When running next dev (development mode), Next.js automatically loads .env.development , and when running next build (production mode), it loads .env.production . Only variables prefixed with NEXT_PUBLIC_ are exposed to the browser; others are server-side only.
You, as a developer, need to test on port 8080 with verbose logs. Instead of modifying the committed file (causing merge conflicts), you create .env.local :
Keeping variables localized to .env.development prevents production database connection strings, high-tier API keys, or security tokens from accidentally bleeding into local work environments. .env.development
: If you have both .env and .env.development , most tools give priority to the more specific file ( .env.development ) during local runs. .env.development .env.production Loaded during npm start / dev npm run build API Endpoints localhost:5000 ://myapp.com Debug Mode Usually true Always false Git Status If you'd like, I can help you with:
DEV_USER_EMAIL=dev@example.com DEV_USER_PASSWORD=devpass123
The testing environment has its own distinct priority: This ensures new developers can get started immediately
.env.development is a file used to store environment variables specific to the development environment. It is a variation of the popular .env file, which is used to store environment variables for different environments. The .env.development file is typically used in conjunction with other .env files, such as .env.test , .env.staging , and .env.production , to manage environment-specific variables.
Create a file named .env.development in the root of your project.
// ❌ NEVER expose API keys on the client const stripeKey = process.env.REACT_APP_STRIPE_KEY; Only variables prefixed with NEXT_PUBLIC_ are exposed to
Never copy production secrets, real user data, or live encryption keys into .env.development . Use sandbox environments, local test databases, and mock APIs exclusively. Troubleshooting Common Issues Variables Return 'undefined'
The .env.development file typically contains "safe" or local-only information. Key examples include:
Remember: .env files are a configuration tool, not a security solution. For production deployments and sensitive credentials, always use dedicated secret management solutions. But for streamlining your development workflow and managing environment-specific settings, .env.development is an invaluable asset in every modern developer's toolkit.