How Push Notifications Work

A lot of elements have to come together for push notifications to work. Read this explanation to find out what’s happening behind the scenes.

How Push Notifications Work

Push notifications are one of the most important features of modern smartphones. Without them, how would you know when you’ve been tagged in a Facebook photo? Or when you receive a new email? Can you imagine life without those little red circles?

Push notifications are a big part of our daily lives in the age of the smartphone, but many people take them for granted without knowing anything about how they work. Various people and services must work together before that seemingly simple push notification can pop up on your device’s screen.

Push notifications come from apps running in the background. When a certain condition is triggered, the information is pushed (hence the name) from the server, and you’re phone goes “ding”.

Various elements work together to show that little red circle

Push notifications are the counterpart of pull notifications. Pull notifications are generated when the user asks a server for information. Push notifications are sent from the server without needing to receive a request first. That is what allows them to appear on your home and lock screen.

That’s simplifying it a lot though. There are several elements involved that make sure your apps can keep you up to date via push notifications.

Operating system push notification service

The first element is something called an operating system push notification service (OSPNS). Apple’s iOS, Google’s Android, Windows, Amazon’s Fire OS and Blackberry each have their own OSPNS.

App publisher

The person or organisation that publishes an app must enable it for use with one or more of the operating system push notification services. The publisher first registers their app with one or more OSPNSs, then the service will give the publisher an application-programming interface (API). The API is the code that allows the app to interact with the OSPNS.

Client app

Each different OS (Android, iOS, etc.) has an app that comes with the user’s phone. Incoming notifications are received by this software after being sent from the server.

Software development kit (optional)

Each OS also has what’s known as a software development kit (SDK). This isn’t necessary for push notifications to work. Rather, it offers greater possibilities for analysis. The SDK also has other functions, for example; the Android SDK is also used with Android Debug Bridge (ADB).

When a user downloads and installs an app, codes called unique identifiers are generated. These identify the app and the phone to the OSPNS. The unique identifiers are then sent to the publisher and to the OSPNS.

The publisher writes the text of their app notifications and also defines the conditions under which they are triggered. The publisher can also decide upon what delay there is (if any) between the trigger and the sending of the notification.

Some publishers set all of this up themselves, but there are also companies (such as Urban Airship) dedicated to providing this as a service for app publishers. The benefit of this service for publishers is that it leaves them with more time to focus on perfecting the app’s core functionality.

That’s a brief rundown of what’s going on behind the scenes whenever a new alert pops up on your smartphone. That’s way more than initially meets the eye right?