What Is Node.js?

What Is Node.js?

Node.js is a program that lets your computer run JavaScript without a web browser. JavaScript is the language that makes web pages interactive. For a long time, it only worked inside browsers. Node.js took that same language and made it work anywhere on your computer — so you can use it to build tools, scripts, and even full websites.

Where Node.js Shines

Node.js is good at tasks where the program spends time waiting — for files, for data, or for messages from other computers. Common uses include:

• Websites and web services that respond to many visitors at once
• Small tools that automate boring tasks, like renaming files
• Chat apps and live updates, where data flows constantly

Big names like Netflix and PayPal use it for exactly these reasons.

Installing Node.js

Installing is simple:

1. Go to the official website, nodejs.org.
2. Download the version marked "LTS" (Long Term Support — the stable one).
3. Run the installer and follow the steps.

To check it worked, open your terminal (a text window for typing commands) and type:

node --version

You should see a number like v20.11.0.

Running Your First Script

Create a file called hello.js with one line:

console.log('Hello, Node.js!');

Then run it from the terminal:

node hello.js

The message appears in your terminal. You just ran JavaScript outside a browser.

Exploring with the REPL

Node.js also has a playground called the REPL. That stands for Read, Evaluate, Print, Loop — it reads what you type, runs it, prints the result, and waits for more. Type this in your terminal:

node

You get a > prompt. Try typing 2 + 2 and press Enter. Try Math.max(3, 9). Type .exit (or press Ctrl+C twice) to leave.

The REPL is perfect for testing small ideas before writing them into files.