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How do you handle environment variables in Node.js?

Q: How do you handle environment variables in Node.js?

**TL;DR.** Read environment variables from process.env . Keep secrets and per-environment settings **out of code** — load them from the real environment (or a .env file in dev via --env-file /dotenv), **validate** them at startup, and never commit .env . This follows the 12-factor "config in the environment" principle. .env / shell / secrets manager process.env <text class='d-sub' x='272' y='90' tex

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This question checks how candidates manage configuration for different deployment environments.

environment variablesconfigurationsecurity

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Validate env once with zod

import { z } from 'zod';

const Env = z.object({
  NODE_ENV: z.enum(['development', 'production', 'test']),
  PORT: z.coerce.number().default(3000),
  DATABASE_URL: z.string().url(),
});

export const env = Env.parse(process.env);   // throws at boot if invalid
// Run dev with: node --env-file=.env src/index.js

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