env-validator

Zero-dependency CLI to validate and lint .env files. Catches common mistakes before they break your app.

Install

npm install -g env-validator

Or run without installing:

npx env-validator

Usage

# validate .env in current directory
env-validator

# validate a specific file
env-validator .env.production

# validate multiple files
env-validator .env .env.staging

# only show errors, hide warnings
env-validator --quiet

What it checks

| Check | Severity | |-------|----------| | Missing = sign | error | | Empty key | error | | Invalid characters in key (-, spaces, etc.) | error | | Key starts with a number | error | | Unmatched quotes in value | error | | Lowercase key (should be UPPER_CASE) | warning | | Empty value | warning | | Duplicate key | warning | | Unquoted value with spaces | warning | | Inline comment missing space before # | warning |

Example output

Validating .env
18 lines · 5 keys

  ✗ line   3 [error]  Missing '=' — not a valid KEY=VALUE pair
  ⚠ line   7 [warn ]  Key "db_host" should be UPPER_CASE
  ✗ line  12 [error]  Key "NAME" has unmatched quotes in value
  ⚠ line  15 [warn ]  Duplicate key "PORT" (first seen on line 4)

  2 error(s)  2 warning(s)

Options

| Flag | Description | |------|-------------| | --quiet | Only show errors, suppress warnings | | --no-color | Disable colored output (good for CI logs) | | --help | Show help |

Exit codes

• 0 — no errors (warnings don't affect exit code)
• 1 — one or more errors found

This makes it easy to use in CI pipelines:

# GitHub Actions example
- run: npx env-validator .env.example

Running tests

npm test

License

MIT