PORT=5173 VITE_API_URL=http://localhost:3000 DEBUG=true LOG_LEVEL=verbose SECRET_KEY=dev-super-secret-do-not-use-in-prod
: Variables must be alphanumeric, starting with letters, and use underscores ( _ ) instead of hyphens or spaces. By global convention, they are capitalized.
The .env.development file is a cornerstone of this philosophy, acting as a dedicated configuration hub specifically for your local development environment.
: Credentials for sandbox environments or mock payment gateways (like Stripe’s test keys). Best Practices for Security and Efficiency Environment variables - Vercel .env.development
: For development mode ( npm start ), files load in the following order of priority: .env.development.local (highest priority) → .env.development → .env.local → .env (lowest priority).
# .env.development VITE_API_URL="http://localhost:5000/api" DB_PASSWORD="super_secret_local_password" # Only available in vite.config.js Use code with caution.
DB= # What database connection? URL= # Which URL? FLAG= # Which feature? : Credentials for sandbox environments or mock payment
# .env.development NEXT_PUBLIC_ANALYTICS_ID="UA-DEV-12345" # Available everywhere STRIPE_SECRET_KEY="sk_test_123" # Server-side only Use code with caution. In your code, access them via the standard Node.js syntax: javascript const analyticsId = process.env.NEXT_PUBLIC_ANALYTICS_ID; Use code with caution. 3. Node.js (Express, Fastify) with dotenv
Environment variables are dynamic values that affect the way running processes behave on a computer. By isolating these variables into a specific file, developers ensure that their local laptops run configurations tailored for coding, debugging, and testing—without touching production databases or external live APIs. The Anatomy of a .env File
: Use .env.development for team-shared defaults, .env.development.local for personal overrides, and .env.local for cross-environment personal preferences. DB= # What database connection
commit .env.development to Git. Add it to your .gitignore file immediately.
: Quotes are optional unless the value contains spaces or special characters. Use double quotes if you need to use escape sequences (like \n ).