What is a Real-Time App and Why Does it Matter?

4 min readMichael Carroll on Jan 9, 2023

At the core, real-time technology is the sending (publishing) and receiving (subscribing) of data “as it happens” in real life. Information or data is sent and presented in milliseconds. So what is a real-time app? Below we’ll define real time applications, provide examples of a real time app, and more.

What is a real time app?

A real time app (also known as a real-time application, or realtime) is an application that sends and receives data in milliseconds.

Is a real time application the same an as online application?

Yes and no. While real time applications are all online, not all online applications are in real time. Some applications that are online may not have any real time functionality. An example would be an application that you need to manually refresh or reload the page to see changes. While Instagram has real time functionality, your feed needs to be manually reloaded to see the latest content. 

Real time applications are used in practically every industry, platform, system, and game. For example, when you receive notifications from online games, or direct message notifications from Instagram. These are all done in real time.

Real time app examples:

When someone sends you a message in a chat app, and you receive that message on your phone, or you get a mobile push notification, that notification or message is received in ‘real time.’

text message received animated gif real-time applications

Receiving a mobile push notification in real time

When you watch your taxi on your phone, and it smoothly moves along the street towards you, the map and taxi location is updating in ‘real time.’

taxi application map animated gif real-time applications

Taxi dispatch app GrabTaxi‘s real-time map

In a multiplayer game, when two players move their characters, player position is updated on both browsers in ‘real time’

multiplayer game animated gif real-time applications

Robot Onslaught by Thomas Hunter

When you click a button on your phone to change channels on your TV, that signal is sent in ‘real time.’

remote control animated gif real-time applications by Ian Jennings

When you’re walking to your house, and your lights turn on based on your geolocation, that signal is sent in ‘real time.’

home automation smart home animated gif real-time applications

Home automation app Revolv uses geolocation to trigger devices

PubNub exists for real time apps

The next question is, why does PubNub exist? To make real-time apps happen, mobile devices are sending little tiny packets of data to one another in 1/10 second or less (which is considered real-time speed).

This doesn’t just magically happen. The app developer needs a ‘real-time’ data stream network to send those little tiny packets of data. Building a ‘real-time’ infrastructure yourself is hard, can get expensive, and is a large burden on development time. And once it’s built, you then have to maintain and scale that network to ensure uptime for your application.

This is often why many of our customers often go through a build vs buy stage, and soon realize that building real time app infrastructure themselves isn’t plausible. Developers will first try to build real-time apps with an open source protocol, but soon find it’s expensive, time consuming, and tough to scale.

How to Build a Real Time App on a Data Stream Network

So app developers use our data stream network, which we’ve built and globally scaled for the developer. This saves them time and money (they don’t have to build it themselves, we did it for them). Businesses like PubNub are known by many names: IaaS (infrastructure-as-a-service), data streaming services, real-time data stream networks, real-time networks, etc.

The value to the developer is that they can use our infrastructure (our network) so that they can focus on building their apps. The infrastructure is made up of multiple data centers (massive server rooms spread across the globe) that move (aka, ‘stream’) these small packets of data. This type of infrastructure is called a real-time Data Stream Network. And that’s what we do at PubNub.

How to Create a Real Time Application

Now that you understand what PubNub does, see some

of real-time technology in use. Or if you want to get started right away, sign up for a free account and head over to our short Quick Start Tutorial to get going.