env-sync

CLI tool to sync and validate .env files — detect missing, extra, or mismatched environment variables between .env.example and .env.

Why?

Every project with environment variables has the same problem:

• You add a new config to .env.example but forget to update .env
• Someone deploys without the right env vars set
• You waste hours debugging "undefined is not a function" when it's really DATABASE_URL missing

env-sync catches these before they cause issues.

Install

# Install globally
npm install -g env-sync

# Or use directly with npx (no install needed)
npx env-sync

Usage

Basic comparison

env-sync

Compares .env.example with .env in current directory — shows missing keys.

Auto-fix missing keys

env-sync --fix

Adds all missing keys from .env.example into .env with empty values.

Strict mode (flag extra keys too)

env-sync --strict

Also shows keys in .env that aren't in .env.example.

JSON output (for CI/scripts)

env-sync --json

Outputs machine-readable JSON. Exit code 0 = no issues, 1 = issues found.

Initialize .env.example from .env

env-sync --init

Creates .env.example from your current .env (keys only, no values).

Custom file paths

env-sync --example .env.dev.example --env .env.production

Use in CI (GitHub Actions)

- name: Validate env files
  run: npx env-sync --strict --json

API

const { validate } = require('env-sync');
const result = validate({
  example: '.env.example',
  env: '.env',
  strict: true,
});
// { missing: [...], extra: [...], status: 'ok'|'issues' }

License

MIT