In the world of web applications, real-time updates and communication have become essential features. Traditional request-response architectures are no longer sufficient to meet the demands of modern applications. To overcome these limitations, we attempted to leverage the power of Express.js and Socket.IO to build real-time web applications that enable instant communication between clients and servers. In this blog post, we have shown how we created a real-time chat application using Express.js and Socket.IO in one of our projects.

Setting Up the Project

To get started, make sure you have Node.js installed on your machine. Then, create a new directory for your project and navigate into it using the command line. Run the following commands to set up the project:

Creating the Express.js Server: 

Creating the Client-side HTML: 

Create an HTML file named index.html and add the following code: 

Create a file named server.js and import the required modules: 

<!DOCTYPE html> 



  <title>Real-Time Chat</title> 

  <script src=””></script> 



  <input id=”messageInput” type=”text” placeholder=”Enter your message”> 

  <button id=”sendButton”>Send</button> 

  <ul id=”messageList”></ul> 


    const socket = io(); 

    const messageInput = document.getElementById(‘messageInput’); 

    const sendButton = document.getElementById(‘sendButton’); 

    const messageList = document.getElementById(‘messageList’); 

    sendButton.addEventListener(‘click’, () => { 

      const message = messageInput.value; 

      socket.emit(‘chatMessage’, message); 

      messageInput.value = ”; 


    socket.on(‘chatMessage’, (message) => { 

      const li = document.createElement(‘li’); 

      li.innerText = message; 






Running the Application: 

Start the server by running the following command: 

Open your web browser and navigate to http://localhost:3000. You should see the chat interface. Open multiple browser tabs or windows and start chatting in real time! 


In this blog post, we have shown how to build a real-time web application using Express.js and Socket.IO. We set up an Express.js server and established a WebSocket connection using Socket.IO. With this setup, we created a simple chat application that allows users to send and receive messages in real time. Socket.IO’s event-based communication model and Express.js’ simplicity make it a powerful combination for building real-time web applications. 

Socket.IO offers many more features and options for building sophisticated real-time applications.  If you are looking for a partner for your app development needs using Express.js and, please feel free to reach out our team today!