Field explanations
- Top-level settings define the tool behavior
- Environment-specific blocks override defaults
- Paths are usually relative to the config file or project root
- Secrets should be referenced, not committed
Minimal template
APP_ENV=development API_BASE_URL=http://localhost:3000 # SECRET_TOKEN=replace_me_locally
Common usage patterns
- Keep .env small and reviewable
- Use comments only when the format supports them
- Commit example files with placeholder values
- Validate locally before deploying
Common errors
- Quotes included in value unexpectedly
- Variable not loaded by IDE
- Production platform ignores local file
- Secret committed by accident
Online validation
Validate syntax first, then compare behavior against your deploy target. For JSON-based configs, use the JSON formatter before debugging tool-specific behavior.