Setting Up Your First Node.js Application Step-by-Step

Getting started with Node.js is the first step toward building backend systems, APIs, and full-stack applications using JavaScript. This guide walks you through the complete setup process—from installation to running your first server—without using any frameworks.

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1. Installing Node.js

Node.js is a JavaScript runtime that allows you to execute JavaScript outside the browser.

Steps:

1. Go to the official Node.js website: https://nodejs.org

2. Download the LTS (Long-Term Support) version

3. Install it using the default settings

This installation also includes npm (Node Package Manager), which you’ll use later for managing dependencies.

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2. Verifying Installation

Once installed, you need to confirm that Node.js is correctly set up.

Open your terminal (or command prompt) and run:

node -v

You should see a version number like:

v24.x.x

Now check npm:

npm -v

If both commands return versions, your setup is successful.

💡 Tip: If you ever forget common commands or want quick one-liner solutions for JavaScript/Node tasks, platforms like Practica JS can be very handy for fast reference and practice.

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3. Understanding Node REPL

REPL stands for:

Read – Evaluate – Print – Loop

It’s an interactive environment where you can execute JavaScript code line-by-line.

Start REPL:

node

You’ll see something like:

>

Try this:

console.log("Hello from REPL");

Output:

Hello from REPL

Exit REPL:

.exit

or press:

Ctrl + C (twice)

Why REPL matters:

• Quick testing of JavaScript code

• Debugging logic

• Learning Node interactively

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4. Creating Your First JavaScript File

Now let’s move from interactive mode to writing actual scripts.

Step 1: Create a file

Create a file named:

app.js

Step 2: Add code

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

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5. Running Your Script

To execute the file, navigate to its directory in terminal and run:

node app.js

Output:

Hello, Node.js!

This is your first Node.js execution 🎉

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6. Writing Your First “Hello World” Server

Now let’s create a basic HTTP server using Node’s built-in module (no frameworks).

Step 1: Update app.js

const http = require("http");

const server = http.createServer((req, res) => {
  res.write("Hello World from Node.js Server");
  res.end();
});

server.listen(3000, () => {
  console.log("Server running at http://localhost:3000/");
});

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Step 2: Run the server

node app.js

Step 3: Open browser

Go to:

http://localhost:3000

Output:

Hello World from Node.js Server

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What’s Happening Behind the Scenes?

• require("http") → imports Node’s built-in HTTP module

• createServer() → creates a server instance

• req → incoming request object

• res → response object sent back to client

• listen(3000) → server starts listening on port 3000

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Key Takeaways

• Node.js allows you to run JavaScript outside the browser

• REPL is useful for quick experimentation

• Scripts are executed using the node command

• You can create a basic server without any frameworks

• Node’s core modules (like http) are powerful enough for fundamentals

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What’s Next?

Once you’re comfortable with this setup, you can move on to:

• File system operations (fs module)

• Handling routes manually

• Understanding asynchronous behavior in Node.js

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