</>
DevToolHub

ENV File Generator

Generate .env and .env.example files with preset templates for popular frameworks. Add custom variables, edit values inline, and download both files.

Environment Variables
=
=
=
=
=
=
=
=
=
=
=
=
=
.env
NEXT_PUBLIC_APP_URL=http://localhost:3000  # Public-facing app URL
NEXT_PUBLIC_API_URL=http://localhost:3000/api  # API base URL (client-side)
DATABASE_URL       =postgresql://user:password@localhost:5432/mydb  # Database connection string
NEXTAUTH_SECRET    =your-secret-key-here  # NextAuth.js secret for JWT signing
NEXTAUTH_URL       =http://localhost:3000  # NextAuth.js canonical URL
NEXT_PUBLIC_GA_ID  =G-XXXXXXXXXX  # Google Analytics measurement ID
SMTP_HOST          =smtp.example.com  # Email SMTP server host
SMTP_PORT          =587  # Email SMTP server port
SMTP_USER          =noreply@example.com  # SMTP username
SMTP_PASSWORD      =your-smtp-password  # SMTP password
REDIS_URL          =redis://localhost:6379  # Redis connection URL for caching
NODE_ENV           =development  # Node environment (development/production/test)
.env.example
NEXT_PUBLIC_APP_URL=  # Public-facing app URL
NEXT_PUBLIC_API_URL=  # API base URL (client-side)
DATABASE_URL       =  # Database connection string
NEXTAUTH_SECRET    =  # NextAuth.js secret for JWT signing
NEXTAUTH_URL       =  # NextAuth.js canonical URL
NEXT_PUBLIC_GA_ID  =  # Google Analytics measurement ID
SMTP_HOST          =  # Email SMTP server host
SMTP_PORT          =  # Email SMTP server port
SMTP_USER          =  # SMTP username
SMTP_PASSWORD      =  # SMTP password
REDIS_URL          =  # Redis connection URL for caching
NODE_ENV           =  # Node environment (development/production/test)

How It Works

Select a framework preset to pre-fill common environment variables with sensible placeholder values and descriptive comments. Edit any variable inline, add your own custom entries, or remove ones you do not need. The tool generates two output files simultaneously: a complete .env with all values filled in and an .env.example with values stripped out (safe to commit to version control).

Everything runs in your browser. No credentials or configuration data is sent to any server.

Common Environment Variables by Framework

FrameworkKey VariablesNotes
Next.jsNEXT_PUBLIC_*, NEXTAUTH_SECRET, DATABASE_URLNEXT_PUBLIC_ prefix exposes vars to the browser
ExpressPORT, JWT_SECRET, CORS_ORIGIN, RATE_LIMIT_*All vars are server-side only
DjangoSECRET_KEY, DEBUG, ALLOWED_HOSTS, DATABASE_URLUse django-environ or python-dotenv to load
LaravelAPP_KEY, DB_*, MAIL_*, CACHE_DRIVERLaravel reads .env natively via vlucas/phpdotenv
DockerCOMPOSE_PROJECT_NAME, POSTGRES_*, *_PORTUsed in docker-compose.yml with ${VAR} syntax
AWSAWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_*Prefer IAM roles over access keys in production

ENV File Best Practices

  • Never commit .env to git. Add it to .gitignore immediately. Commit .env.example instead so collaborators know which variables are needed.
  • Use descriptive comments. Future you (or a teammate) will appreciate knowing what SMTP_PORT=587 is for without searching the docs.
  • Keep variable names UPPER_SNAKE_CASE. This is the universal convention across languages and platforms. Avoid spaces, hyphens, or camelCase.
  • Quote values with special characters. If a value contains spaces, equals signs, or hash characters, wrap it in double quotes to prevent parsing errors.
  • Use different files per environment. Maintain separate .env.development, .env.staging, and .env.production files or use a secrets manager for production.
  • Rotate secrets regularly. API keys, JWT secrets, and database passwords should be rotated on a schedule, not left unchanged for years.

FAQ

What is the difference between .env and .env.example?

The .env file contains actual secret values and should never be committed to version control. The .env.example file lists all required variable names with empty values and comments. You commit .env.example so new developers know which variables to configure, then each developer copies it to .env and fills in their own values.

Which frameworks support .env files natively?

Next.js, Vite, and Create React App load .env files automatically. Laravel uses vlucas/phpdotenv built into the framework. For Express/Node.js, install the dotenv package and call require("dotenv").config() at the top of your entry file. Django uses django-environ or python-dotenv.

Should I use .env files in production?

For small projects, .envfiles work fine in production. For larger deployments, use your platform's secrets management: Vercel Environment Variables, AWS Secrets Manager, GCP Secret Manager, or HashiCorp Vault. These provide encryption at rest, access controls, and audit logs that flat files cannot.

How do I access env vars in Next.js client-side code?

Only variables prefixed with NEXT_PUBLIC_ are exposed to the browser bundle. Server-side variables (without the prefix) are only available in API routes, getServerSideProps, and Server Components. This is a security feature: it prevents database credentials and API secrets from leaking to the client.

Building server configs? Generate .htaccess files or create meta tags for SEO.