TypeScript Environment Variables: The Complete Guide
What Are Environment Variables?
Environment variables are key-value pairs your operating system or runtime passes into a process. Think of them as external configuration that stays outside your code. You don't want to hardcode a database URL or an API key — env vars let you change those values between dev, staging, and production without touching a single source file.
How Node.js Exposes Them
Node.js makes every env var available through process.env. It's a plain object where each key is a variable name and each value is a string — or undefined if the variable doesn't exist.
