.env.example Generator
Parse your .env to create a safe template, build one from scratch, or compare two .env files side-by-side.
How to Use the .env.example Generator
- Parse mode — paste your existing .env file. Sensitive values (keys, passwords, tokens) are automatically detected and replaced with placeholder descriptions. Non-sensitive values with obvious defaults (ports, flags) are kept as-is.
- Build mode — construct a .env.example from scratch by adding variables with names, default values, descriptions, and required flags. Group them by section (Database, API, Auth, etc.).
- Compare mode — paste two .env files to see which variables exist in one but not the other. Useful when syncing .env files across environments or finding missing variables.
- Download or copy the generated .env.example and commit it to your repository.
Why .env Files Matter
Environment variables are the standard way to configure applications across different environments (development, staging, production) without hardcoding values in source code. The twelve-factor app methodology specifically requires storing configuration in the environment as one of its core principles. A .env file is a convenient local way to set these variables during development. The dotenv package for Node.js popularized this pattern, and it is now standard practice across virtually all web frameworks.
Security Best Practices
Your .env file contains secrets that must never be committed to version control. Add .env and .env.local to your .gitignore immediately after creating a new project. A .env.example file serves as the safe, committable documentation of what variables the application needs. Anyone who clones the repository copies .env.example to .env and fills in their own credentials. This pattern prevents accidental secret exposure while ensuring developers know exactly what to configure.
Detecting Sensitive Values
This tool automatically flags values as sensitive when the variable name contains keywords like KEY, SECRET, PASSWORD, TOKEN, PASS, PRIVATE, CREDENTIAL, or AUTH. These are replaced with descriptive placeholders like your-api-key-here in the output. Non-sensitive values with obvious defaults — like PORT=3000 or NODE_ENV=production — are preserved as-is, since they do not expose any secrets.
Environment File Hierarchy
Frameworks like Next.js, Vite, and Create React App support multiple .env files with a defined priority order. From lowest to highest priority: .env (base defaults), .env.local (local overrides, always gitignored), .env.development / .env.production (environment-specific), .env.development.local / .env.production.local (local environment-specific overrides). Understanding this hierarchy prevents confusion when variables seem to be ignored — a higher-priority file is likely overriding them. Use our GitHub Actions Generator to see how to use secrets in CI/CD pipelines.
Grouping Variables by Section
For larger applications with many environment variables, organizing them into sections with comment headers significantly improves readability. Common sections include Database (connection strings, pool size), External APIs (API keys, base URLs), Authentication (JWT secrets, OAuth credentials), Storage (S3 buckets, CDN URLs), Feature Flags (boolean toggles), and Application Settings (port, log level, environment name). The Build mode in this generator lets you assign each variable to a named section, which then appears as a comment block in the output.