env-validator-gen

Scans your source files for process.env.* usage and generates a typed validation schema that crashes early if any required variables are missing — no manual list maintenance needed.

Install

npm install -g env-validator-gen
# or run directly
npx env-validator-gen ./src

Usage

Given source files that use environment variables:

// src/db.ts
const client = new Client({ url: process.env.DATABASE_URL });

// src/auth.ts
const secret = process.env.JWT_SECRET;
const expiry = process.env.TOKEN_EXPIRY;

Run the scanner:

npx env-validator-gen ./src

Generates src/env.ts:

// Auto-generated by env-validator-gen. Do not edit manually.
import { z } from 'zod';

const envSchema = z.object({
  DATABASE_URL: z.string().min(1, 'DATABASE_URL is required'),
  JWT_SECRET: z.string().min(1, 'JWT_SECRET is required'),
  TOKEN_EXPIRY: z.string().min(1, 'TOKEN_EXPIRY is required'),
});

export const env = envSchema.parse(process.env);
export type Env = z.infer<typeof envSchema>;

Import it at your app's entry point and it validates all env vars at startup — throwing a descriptive error if any are missing.

Options

| Flag | Description | |------|-------------| | --out <file> | Output file path (default: src/env.ts) | | --raw | Generate a plain Node.js validator instead of Zod | | --dotenv | Add import 'dotenv/config' to the generated file | | --print | Print to stdout instead of writing a file |

Examples

# Custom output path
npx env-validator-gen ./src --out config/env.ts

# Plain Node.js validator (no Zod dependency)
npx env-validator-gen ./src --raw

# With dotenv auto-load
npx env-validator-gen ./src --dotenv

# Preview without writing
npx env-validator-gen ./src --print

Raw mode (no Zod)

With --raw, generates a plain validator with no dependencies:

// Auto-generated by env-validator-gen. Do not edit manually.

const REQUIRED_ENV_VARS = [
  'DATABASE_URL',
  'JWT_SECRET',
  'TOKEN_EXPIRY',
] as const;

const missing = REQUIRED_ENV_VARS.filter((k) => !process.env[k]);

if (missing.length > 0) {
  console.error(`Missing required environment variables: ${missing.join(', ')}`);
  process.exit(1);
}

export const env = process.env as Record<typeof REQUIRED_ENV_VARS[number], string>;

What gets scanned

The scanner detects all three common patterns:

process.env.DATABASE_URL       // dot notation
process.env['DATABASE_URL']    // bracket with single quotes
process.env["DATABASE_URL"]    // bracket with double quotes

Scanned file types: .ts, .tsx, .js, .jsx, .mjs, .cjs

Ignored directories: node_modules, dist, .git, coverage, .next, build

Use as a library

import { scanFiles, scanContent, generateZodValidator, generateRawValidator } from 'env-validator-gen';

// Scan a directory
const keys = scanFiles('./src');

// Or scan a string of code
const keys2 = scanContent('const x = process.env.API_KEY;');

// Generate output
const zodSchema = generateZodValidator(keys, { withDotenvLoad: true });
const rawSchema = generateRawValidator(keys);

License

MIT