🌱 env-schema-gen

Automatically validate environment variables at startup — no boilerplate, no configs.

env-schema-gen helps you catch broken or misconfigured environment variables before your app runs, by inferring types and validating them instantly.

✨ Why env-schema-gen?

In Node.js:

• process.env values are always strings
• Missing or wrong env values cause runtime crashes
• Writing manual env validation is repetitive and boring

👉 env-schema-gen acts as a startup guard for your application.

If env variables are wrong → your app will not start.

📦 Installation

npm install env-schema-gen

🚀 Quick Start (30 seconds)

require("dotenv").config();
const { generateEnvSchema } = require("env-schema-gen");

// Validate envs before app starts
generateEnvSchema(process.env);

console.log("Environment is valid ✅");

That’s it.

🧠 How it works

env-schema-gen:

Reads process.env

Infers types (string, number, boolean)

Validates values at startup

Throws clear errors if something is wrong

🛠 Type Inference Examples ENV Value Inferred Type 3000 number true boolean false boolean hello string ❌ Example Error (Fail Fast)

.env

PORT=abc

generateEnvSchema(process.env, { PORT: "number" });

Output:

ENV validation error: PORT expected number, got string ("abc")

Your app stops immediately — no silent failures.

🎯 Using Type Overrides (Recommended)

Inference works for most cases, but you can enforce strict types:

generateEnvSchema(process.env, { PORT: "number", DEBUG: "boolean", });

This guarantees:

PORT is always a number

DEBUG is always boolean

✅ Supported Types

string

number

boolean

📌 Real World Example (Express) require("dotenv").config(); const express = require("express"); const { generateEnvSchema } = require("env-schema-gen");

generateEnvSchema(process.env, { PORT: "number", });

const app = express(); app.listen(process.env.PORT, () => { console.log("Server running 🚀"); });

💡 When should I use this?

Use env-schema-gen if you:

Deploy Node.js apps

Use .env files

Want early failure instead of runtime bugs

Don’t want heavy validation libraries

🧩 What this package is NOT

❌ Not a full config framework

❌ Not a schema definition DSL

❌ Not tied to TypeScript

It’s intentionally small, fast, and simple.

🔮 Roadmap (Future Versions)

Required vs optional variables

Default values

.env file parsing

Zod / Joi schema output

CLI: npx env-schema-gen

🪪 License

MIT © Shubham Tidke

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