envcheck

Validate your .env files against a schema. Catch missing vars, wrong types, and sneaky typos before your app explodes in production.

Why?

You've been there — deploy fails because DATABASE_URL is missing, or PORT is set to "lol". .env.example files help but nobody reads them. envcheck lets you define a schema and validates against it. Zero deps.

Install

npm install envcheck

Usage

1. Create a schema file (envcheck.schema.json)

{
  "DATABASE_URL": { "required": true, "type": "url" },
  "PORT": { "required": true, "type": "number", "default": 3000 },
  "NODE_ENV": { "required": true, "enum": ["development", "staging", "production"] },
  "API_KEY": { "required": true, "minLength": 32 },
  "DEBUG": { "required": false, "type": "boolean" },
  "MAX_CONNECTIONS": { "required": false, "type": "number", "min": 1, "max": 100 }
}

2. Run it

npx envcheck

Or validate a specific file:

npx envcheck --env .env.production --schema envcheck.schema.json

3. Programmatic API

const { validate } = require('envcheck');

const result = validate({
  schema: './envcheck.schema.json',
  env: './.env'
});

if (!result.valid) {
  result.errors.forEach(e => console.error(e.message));
  process.exit(1);
}

Schema Options

Field	Type	Description
required	boolean	Must be present (default: false)
type	string	string, number, boolean, url, email, json
default	any	Default value if not set
enum	array	Allowed values
minLength	number	Minimum string length
maxLength	number	Maximum string length
min	number	Minimum numeric value
max	number	Maximum numeric value
pattern	string	Regex pattern to match
description	string	Human-readable description (for docs/Errors)

CLI

Usage: envcheck [options]

Options:
  --env <path>       Path to .env file (default: .env)
  --schema <path>    Path to schema file (default: envcheck.schema.json)
  --strict           Fail on variables not in schema
  --json             Output as JSON
  --quiet            Only show errors
  -h, --help         Show help
  -v, --version      Show version

Example Output

✗ 2 errors found in .env

  MISSING   DATABASE_URL    Required variable not set
  INVALID   PORT            Expected number, got "abc123"

✓ 6 variables checked

License

MIT