Guide · Reviewed 2026-09-04
What Is a .env File?
A .env file is a plain-text list of named configuration values, usually written as KEY=VALUE pairs. Development tools commonly load those values into a process environment so configuration such as ports, service URLs, feature flags, and credentials can vary without changing application code.
Written and reviewed by EnvDesk product team. Last updated .
What does a .env file look like?
Most dotenv parsers accept one assignment per line. Blank lines and lines beginning with # are commonly treated as comments, while exact quoting and expansion behavior depends on the parser.
- APP_PORT=3000
- API_URL=https://api.example.com
- DEBUG=false
Is .env a universal standard?
No single specification governs every dotenv implementation. Node.js, Python libraries, Docker Compose, frameworks, and shell tools can disagree about quoting, multiline values, variable expansion, and file precedence. Check the documentation for the runtime that actually loads your file.
Should .env files be committed?
Files containing credentials should normally be excluded from version control. A value-free .env.example can document required keys, but generated examples still need human review so comments and safe defaults remain useful.