Environment Variables (.env) Generator
Build properly formatted .env files in seconds. Add variables row by row, generate the output, and copy it directly into your project.
Variables
Add your variables
Output
.env Preview
# Your .env output will appear here
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TL;DR
A fast .env generator for everyday dev config
A .env file holds key=value configuration that your application reads at startup. Use this tool to build .env content in your browser without installing anything. Nothing you type is sent to a server.
Basis: The Twelve-Factor App methodology and dotenv convention.
What Is a .env File?
What is a .env file?
A .env file is a plain text file placed in the root of a project. Each line
holds one configuration value in the format KEY=value. Applications load these values before the main code runs so that
secrets, API endpoints, and environment-specific flags never need to
be hardcoded in source files.
The convention was popularized by the Twelve-Factor App methodology, which recommends storing all configuration in the environment rather than in the codebase.
Key rule: a .env file is a convenience for local development. In production, set real environment variables through your hosting platform rather than shipping a .env file with your build.
How It Works
How environment variables work
When a Node.js process starts, it can call require('dotenv').config()
which reads the .env file and injects each key into process.env. From that point, any module in the application can read process.env.PORT or
process.env.DATABASE_URL without needing to import the .env file directly.
Other runtimes and frameworks have equivalent mechanisms. Vite reads
.env files automatically and exposes variables prefixed with VITE_ to client-side code. Next.js supports multiple .env files (.env.local, .env.production) and exposes variables prefixed with NEXT_PUBLIC_ to the browser.
Use Cases
Common use cases by framework
Node.js
Use the dotenv package to load .env variables into process.env at startup. Place require('dotenv').config() at the very top of your entry file.
React / Vite
Prefix variables with VITE_ so Vite exposes them to client-side code via import.meta.env. Variables without the prefix are server-only.
Next.js
Next.js loads .env, .env.local, and environment-specific files automatically. Prefix with NEXT_PUBLIC_ to make a variable available in the browser.
Docker / Compose
Reference a .env file using the env_file key in docker-compose.yml, or pass individual variables with the environment key for container-level overrides.
Laravel
Laravel reads .env automatically via the vlucas/phpdotenv library bundled with the framework. Access values with env('KEY') or config() helpers.
Django / Python
Use python-decouple or django-environ to read .env files. Both libraries support type casting and default values for missing variables.
CI/CD pipelines
Most CI platforms (GitHub Actions, GitLab CI, CircleCI) let you store secrets as masked variables in the project settings. These are injected into the build environment automatically.
Best Practices
Environment variable best practices
- 1
Never commit .env to version control
Add .env and all .env.* variants (except .env.example) to your .gitignore. A leaked secret in git history is nearly impossible to fully remove.
- 2
Commit a .env.example file instead
A .env.example file lists every variable name with safe placeholder values. It documents what a new developer needs to configure without exposing real credentials.
- 3
Separate environments
Use different .env files or platform-level variables for development, staging, and production. Never reuse production credentials in a development environment.
- 4
Rotate credentials regularly
Treat API keys and secrets like passwords. Rotate them on a schedule and immediately after any suspected exposure.
- 5
Use uppercase key names
By convention, environment variable names are UPPER_SNAKE_CASE. This avoids collisions with shell variables and makes secrets visually distinct from regular code variables.
- 6
Quote values with spaces
If a value contains spaces or special characters, wrap it in double quotes: GREETING="Hello World". Most loaders handle quoted values correctly.
Common Examples
Common environment variable examples
These variables appear across most web applications. Their exact values change per environment.
| Variable | Example value | Purpose |
|---|---|---|
| PORT | 3000 | HTTP server listen port |
| NODE_ENV | development | Runtime environment flag |
| DATABASE_URL | postgres://user:pass@localhost/db | Full database connection string |
| API_KEY | sk-xxxxxx | Third-party API authentication |
| JWT_SECRET | a-long-random-secret | JSON Web Token signing key |
| NEXT_PUBLIC_SITE_URL | https://example.com | Public base URL for the app |
| REDIS_URL | redis://localhost:6379 | Redis connection string for caching |
| SMTP_HOST | smtp.mailservice.com | Email server hostname |
How To Use It
How to use this .env generator
The tool follows a straightforward workflow. No setup required.
- 1
Open the Generator tab and click Add Variable to create your first row.
- 2
Enter a variable name in uppercase (for example PORT or DATABASE_URL) and its value in the next field. Add an optional inline comment if needed.
- 3
Add more rows for each variable your application needs. Rows with empty names are skipped automatically.
- 4
Click Generate .env File to build the formatted output. Review the preview area to confirm the result.
- 5
Click Copy Output to place the full .env content on your clipboard, then paste it into a .env file in your project root.
FAQ
Common .env questions
Direct answers to the most common questions about .env files, security, and tooling.
What is a .env file?
A .env file stores environment variables as KEY=value pairs used to configure apps securely without hardcoding secrets.
Is a .env file secure?
A .env file is only as secure as its storage. The file itself is plain text, so anyone who can read it can see every value. Keep secrets out of version control, restrict file permissions to the application user, and rotate credentials regularly.
Should .env be committed to Git?
No. You should add .env to your .gitignore file and never commit it. Instead, commit a .env.example file that lists every variable name with placeholder values so other developers know what to configure without exposing real secrets.
How do I create environment variables for my app?
Use the Generator tab above to build key=value pairs row by row. Add an optional comment to any variable, then click Generate .env File. The formatted output is ready to paste into a .env file in your project root.
What apps and frameworks use .env files?
Most modern frameworks and runtimes support .env files natively or through a library. Common examples include Node.js with dotenv, React and Vite with VITE_ prefix variables, Next.js with NEXT_PUBLIC_ prefix, Docker Compose with env_file, Laravel with its built-in .env loader, and Django with python-decouple or django-environ.
Is this .env generator tool safe to use?
Yes. The generator runs entirely in your browser. No input is sent to a server, stored remotely, or shared with third parties. You can paste real secrets safely because nothing leaves your device.
What is a valid environment variable name?
By convention, environment variable names use uppercase letters, digits, and underscores only, and they must not start with a digit. The strict POSIX pattern is ^[A-Z_][A-Z0-9_]*$. Some runtimes allow lowercase names, but uppercase is the most portable convention.
Sources / References
Sources / References
These sources underpin the conventions, rules, and framework behavior described on this page.
- The Twelve-Factor App: Config : Methodology for storing config in the environment separate from code.
- dotenv on npm : The most widely-used Node.js library for loading .env files.
- Vite environment variables : How Vite loads and exposes environment variables with the VITE_ prefix.
- Next.js environment variables : Next.js documentation on .env files and NEXT_PUBLIC_ exposure.