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  • Writer's pictureMatt Burrell

Why You Should Build Real-time Applications

Updated: Feb 16, 2023

Real-time features are an essential part of modern web applications. Users want the same rich, fast, and smooth experience that they get with native apps.

In this article, I discuss why you might want to consider building a real-time application and look at some of the technical challenges involved.

What is a real-time application?

A real-time application is one where the server sends updates to a client instantaneously. An example would be how messages automatically appear in messaging applications like WhatsApp.

In traditional web applications updates are ‘pulled’ from the server whenever they’re needed. This is usually in response to a request made by the client, i.e. a browser or mobile device. The server then responds to the client requests with the required data.

Real-time applications are a good way of keeping users updated with live, or streaming, data.

How do real-time applications work?

In modern real-time applications, a special type of connection is established between the client and server. This connection allows the server to push updates directly to the client without the client requesting it.

A legacy way of developing a real-time application is through polling, where a client intermittently polls the server to check if any updates have occurred. However, polling isn’t a scalable solution for providing live updates and isn’t suited for handling streaming data, which is becoming more and more prevalent.

Nowadays real-time functionality is typically achieved using either Server-Sent Events (SSE) or WebSockets. The advantage of a WebSocket connection, however, is that it allows two-way communication. With Server-Sent Events, the server is able to push data to clients, but clients can’t talk back to the server over the same connection. A WebSocket connection on the other hand allows communication in both directions.

Choosing which of these two technologies to use depends on which browsers and devices you need to support. Older browsers (like some versions of Internet Explorer) don’t support server-sent events or WebSockets. In this case, you would need to revert to polling (or better long-polling) to add ‘real-time’ features.

Trying to manage connections (and fall-backs to polling) can become complicated. Luckily there are some great technologies you can use that do all the grunt work for you.

For example, Socket.IO, SignalR or Pusher. Choosing the right tool requires careful thought and consideration of your existing tech stack.

Examples of real-time applications

Normally you would only add real-time functionality to the parts of your app that require live updates. One of the most obvious use cases would be a chat feature allowing users to message each other in real time.

But other use cases exist such as dashboards that require live updates, online gaming, collaboration tools, live auction sites, stock tickers, video conferencing, and real-time file sharing.

These examples are ‘high-level’ but when you combine them together into specific use cases you can build very powerful and user-friendly apps.

Advantages of building real-time applications

By including real-time features in your application you’re adding some solid benefits for both your users and your business.

  • Real-time features allow users to be proactive rather than reactive. Users can respond and handle events almost as they happen rather than clicking a refresh button.

  • Real-time features are more engaging for the user – think of social media applications and their addictive nature.

  • Real-time applications fit nicely with streaming data sources. They allow users to see live data and analytics as it comes in.

  • Real-time applications can improve business processes and collaboration between users. They enable new types of tools to be built and therefore create new business opportunities.

  • Real-time features can work well with recommendation engines. By integrating your app with machine learning algorithms, you can improve users’ experience and generate more revenue through up-selling and referrals by pushing recommendations to users while they are interacting with your application.

The challenges of building real-time applications

Technologies such as Socket.IO, SignalR and Pusher make building real-time applications much easier. But other technical challenges remain.

Before going into production with real-time apps, you need to consider scalability, security, deployment and infrastructure cost. You need to design your application’s data flow and events.

You need to consider how your app will integrate with your existing architecture, applications and tools. Databases (relational and NoSQL), for example, aren’t designed to push real-time data to clients so designing a robust real-time architecture is essential.


Real-time applications aren’t the future, they’re already well-established and here to stay. There are clear benefits to adding real-time capability to your applications for both users and your business.

But designing and building real-time applications requires expertise. The right tools and architecture need to be in place to ensure your app scales, integrates with your existing infrastructure and remains secure.

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