DEV Community

Ezekiel Umesi
Ezekiel Umesi

Posted on

How to Build a Simple Node.js Server from Scratch — A Step-by-Step Guide

Are you ready to create your first backend project with Node.js? In this post, you’ll learn how to build a basic Node.js HTTP server that handles different routes and sends back responses — all using core Node modules (no frameworks like Express yet!).

Let’s break it down step by step and explain exactly what’s happening behind the scenes. 💡

🛠️ Step 1: Set Up Your Project

Before writing any code, we need a place to put it:

mkdir my-nodejs-server
cd my-nodejs-server
npm init -y
Enter fullscreen mode Exit fullscreen mode

This creates a new project folder and initializes it with a default package.json file.

✨ Step 2: Create Your Server File

Now let’s create the file that will run your server:

touch server.js
Enter fullscreen mode Exit fullscreen mode

Open server.js in your code editor (VS Code, Vim, or anything else you like).

💻 Step 3: Write Your First HTTP Server

🔹 1. Import the HTTP Module 

const http = require('http');
Enter fullscreen mode Exit fullscreen mode

👉 This brings in Node.js’s built-in http module, which lets us create web servers. No need to install anything extra!

🔹 2. Create the Server 

const server = http.createServer((req, res) => {
    // Request handler logic goes here
});
Enter fullscreen mode Exit fullscreen mode
  • req: The request object (contains details about the request — like the URL and method).
  • res: The response object (we’ll use this to send data back to the browser).

🔹 3. Handle Routes

Now let’s respond based on the URL path requested:

const server = http.createServer((req, res) => {
    if (req.url === '/') {
        res.statusCode = 200;
        res.setHeader('Content-Type', 'text/plain');
        res.end('Hello, World! 🌍\n');
    } else if (req.url === '/about') {
        res.statusCode = 200;
        res.setHeader('Content-Type', 'text/plain');
        res.end('About Us 📖\n');
    } else {
        res.statusCode = 404;
        res.setHeader('Content-Type', 'text/plain');
        res.end('Page Not Found 🚨\n');
    }
});
Enter fullscreen mode Exit fullscreen mode

What’s happening here?

  • We inspect req.url to determine which page was requested.
  • We respond with appropriate text for /, /about, or anything else (which returns a 404).

🔹 4. Start Listening for Requests

Finally, let’s make our server start listening:

const port = 3000;
const hostname = '127.0.0.1';

server.listen(port, hostname, () => {
    console.log(`Server running at http://${hostname}:${port}/ 🎉`);
});
Enter fullscreen mode Exit fullscreen mode

✅ 127.0.0.1 is your localhost IP.
✅ 3000 is the port where the server will run.
✅ The callback confirms when the server is up.

📜 Full Code: server.js 

const http = require('http');

const server = http.createServer((req, res) => {
    if (req.url === '/') {
        res.statusCode = 200;
        res.setHeader('Content-Type', 'text/plain');
        res.end('Hello, World! 🌍\n');
    } else if (req.url === '/about') {
        res.statusCode = 200;
        res.setHeader('Content-Type', 'text/plain');
        res.end('About Us 📖\n');
    } else {
        res.statusCode = 404;
        res.setHeader('Content-Type', 'text/plain');
        res.end('Page Not Found 🚨\n');
    }
});

const port = 3000;
const hostname = '127.0.0.1';

server.listen(port, hostname, () => {
    console.log(`Server running at http://${hostname}:${port}/ 🎉`);
});
Enter fullscreen mode Exit fullscreen mode

⚡ Step 4: Run and Test Your Server

Start the server:

node server.js
Enter fullscreen mode Exit fullscreen mode

Now open your browser and visit:

To stop the server, hit Ctrl + C in your terminal.

🧠 How It All Works Behind the Scenes

Here’s a simplified flow:

  1. The browser sends a GET request to your server.
  2. Node’s http module captures it.
  3. Your code checks the requested route (req.url).
  4. A response is built and returned with res.end().
  5. The browser receives and displays it.

🛤️ Key Takeaways

Concept Description
req.url The path the client is requesting (/, /about, etc.)
res.statusCode Sets HTTP status like 200 (OK) or 404 (Not Found)
res.setHeader() Tells the browser what type of content it’s getting
res.end() Ends the response and sends it to the client

🎉 Final Words

You just built a fully functioning Node.js HTTP server with zero dependencies. 🎉

It’s a simple project — but a foundational one. From here, you can build more complex backend systems and eventually integrate databases, authentication, REST APIs, and beyond.

Happy coding! 💻✨

Top comments (0)