---
title: Getting started with Socket.io
description: This tutorial shows how to install and use Socket.io server
tags: Socket-io npm socket javascript node-js
products:
- instances
dates:
validation: 2025-04-22
posted: 2018-07-05
validation_frequency: 12
difficulty: beginner
usecase:
- resource-management
ecosystem:
- third-party
---
import image from './assets/scaleway-Hello_world.webp'
import Requirements from '@macros/iam/requirements.mdx'
Socket.io enables real-time event-based communication between one or more clients and a server. It works on every platform, browser, or device and is fast and reliable. Socket.io has two parts: a client-side library that runs in the browser, and a server-side library for Node.js. Both components have an identical API.
Learn how to install and use Socket.io with Express using the `npm` package manager, and create a simple chat server to see the basics of how a client and server work together.
- A Scaleway account logged into the [console](https://console.scaleway.com)
- [Owner](/iam/concepts/#owner) status or [IAM permissions](/iam/concepts/#permission) allowing you to perform actions in the intended Organization
- An [SSH key](/organizations-and-projects/how-to/create-ssh-key/)
- An [Instance](/instances/how-to/create-an-instance/) running Ubuntu 20.04 LTS or later
- Root access to the Instances you want to manage
- Installed [Node.js](https://nodejs.org/en/) (version 18.x or later) and [NPM](https://www.npmjs.com/) on your Instance
## Installing Express.js and Socket.io
Express is a minimal, flexible Node.js web application framework. Install it alongside Socket.io to create a real-time server.
1. Create a project folder and navigate into it:
```
mkdir myapp
cd myapp
```
2. Initialize your project with `npm`:
```
npm init -y
```
This creates a `package.json` file with default settings.
3. Install Express and Socket.io:
```
npm install express@4 socket.io@4 --save
```
4. (Optional) Install jQuery if you want to use it in the front-end:
```
npm install jquery --save
```
## Creating an Express server
1. Create a file called `app.js` file in the `myapp` folder.:
```
nano app.js
```
This file will contain the application code for the Socket.io application.
2. Paste the following code into the application file `app.js`:
```js
const express = require('express');
const http = require('http');
const app = express();
const server = http.createServer(app);
const { Server } = require('socket.io');
const io = new Server(server);
app.use(express.static(__dirname + '/node_modules'));
app.get('/', (req, res) => {
res.sendFile(__dirname + '/index.html');
});
io.on('connection', (socket) => {
console.log('a user connected');
socket.on('disconnect', () => {
console.log('user disconnected');
});
});
server.listen(4200, () => {
console.log('listening on *:4200');
});
```
Save the file and exit `nano`.
3. Create another file called `index.html` in the `myapp` folder:
```
nano index.html
```
This file contains the frontend for the application.
4. Paste the following content into `index.html`:
```html
Socket.io Demo Chat
Hello World!
```
## Running the server
1. Launch the server using Node.js:
```
node app.js
```
2. Open a browser and go to `http://:4200`. You should see the chat interface.
## Enhancing the chat server with client-server interaction
1. Edit `app.js` to handle chat messages:
```js
io.on('connection', (socket) => {
console.log('a user connected');
socket.on('chat message', (msg) => {
io.emit('chat message', msg);
});
socket.on('disconnect', () => {
console.log('user disconnected');
});
});
```
2. Reload the server and try sending chat messages. Any message sent will be broadcast to all connected clients.
You have successfully installed and configured **Socket.io** and **Express** on **Node.js 18.x**. The basic chat server demonstrates real-time bidirectional communication between clients and the server.
You can now build more advanced applications using [Socket.io's robust API](https://socket.io/docs/v4/server-api/).