env-sentinel

Intro

env-sentinel is a lightweight CLI tool for validating .env files in Node.js projects using a simple, human-readable schema format.

It helps developers prevent runtime misconfigurations, especially in multi-environment projects or CI/CD pipelines. With zero dependencies and blazing-fast execution, env-sentinel offers a modern alternative to bloated validators or manual .env.example guessing games.

Whether you're working solo or managing a team, env-sentinel brings confidence, clarity, and automation to your environment variable workflows — without needing to write a line of custom validation logic.

• Zero-dependency .env file checker for Node.js projects.
• Validate your environment variables with a simple schema.
• Auto-generate schema from existing .env files with type inference.
• Perfect for CI/CD pipelines, local dev, and safer config handling.

Features

• Simple schema format (e.g. VAR_NAME=required:number)
• Smart type detection when generating from .env
• Zero dependencies
• CLI-ready: Use in local dev or pipelines
• Initializes .env-sentinel with inferred rules
• Fast fail with clear, colorized output

Installation

npx env-sentinel         # no install needed (recommended)

or install globally/local if preferred:

npm install -g env-sentinel

Initialize schema file (.env-sentinel) from existing .env

npx env-sentinel init

• Auto-detects types like number, boolean
• Creates .env-sentinel in current directory

Re-generate (overwrite existing)

npx env-sentinel init --force

Use custom .env to generate schema

npx env-sentinel init --env-file .env.local

Schema Format (.env-sentinel)

Each line represents a variable and its rule:

DB_HOST=required
DB_PORT=required|number
DEBUG=optional|boolean
NODE_ENV=optional|enum:development,production,test

Supported Rules

Syntax	Description
required	Must be defined
optional	Can be missed
number	Must be a number
string	Can be anything
boolean	Must be true of false
min:value	Is greater than or equal to the specified minimum value; for strings, it checks the length, and for numbers, it checks the numerical value.
max:value	Is less than or equal to the specified maximum value; for strings, it checks the length, and for numbers, it checks the numerical value.
enum:foo,bar	Must match one of listed values

Usage

Check .env file

npx env-sentinel

Defaults:

• .env (env file)
• .env-sentinel (schema file)

Check custom file paths

npx env-sentinel check --env-file .env.production --schema config/prod.schema

Sample Output

On success:

✅ Environment validation passed!

On failure:

🛑 Missing required variable: DB_HOST
⚠️ Insecure value detected: DB_PASS=1234

Why use env-sentinel?

• No runtime bloat — stays lightweight and fast
• More transparent than Joi/Zod configs
• Quick to set up and CI-friendly
• Fits modern DX (type-safe, CLI-ready, focused)

Roadmap (Coming Soon)

• Custom rule plugins
• GitHub Action integration
• VSCode extension
• .env.template generator from schema
• Dry run & suggestion mode

License

MIT — Free to use, modify, and contribute!