What Are Push Notifications?

A push notification is a message sent from an app directly to someone’s mobile device. The message appears even if the device is locked or if the person is inside a different app. Push notifications are useful for sending information to app users in real time.

In this guide, we’ll answer all your burning questions about push notifications, from what they look like to how they work, and so much more. For a basic overview of how Leanplum can help with your push notification strategy, learn more here.

Chapter 1: What Is a Push Notification?

What is a push notification? 

A push notification is a message sent from an app directly to someone’s mobile device. The message appears even if the device is locked or if the person is inside a different app. Push notifications are useful for sending information to app users in real time.

How do push notifications look to an app user? Mobile operating systems are continually evolving and improving the way push notifications work. Below, we review the differences between push notifications on the two biggest mobile operating systems: iOS and Android.

iOS Push Notifications

On iOS, once a user unlocks their homescreen to take an action, the push notification moves into the notification tray. It is then only accessible if a user drags the tray down from the top bar. By nature, iOS push notifications tend to be ephemeral because they are moved out of the homescreen once a user unlocks their device. If a user doesn’t see them on the lock screen, the chances of them interacting with the push notification are low.

Recently, Apple released iOS 10. In the OS update, apps can display customizable content, alongside photos, videos, audio, and gifs, which users are able to download inside the push notification. These are referred to as rich push notifications. For example, when you receive
a push notification that includes a video, you’ll be able to view that video and reply, like, or share right from the push message, without having to go into the app.

Android Push Notifications

On Android, messages “stick” around longer in the lock screen. A user is required to interact with the notification in some form, whether opening or dismissing, for it to disappear. Even after users archive notifications, Android still lets them know they have unread notifications by adding a sticky icon to the top left corner of the home screen. As a result, users are more likely to look at push notifications long after they’re sent.

The most recent update, Android 7.0 Nougat, allows users to respond directly to text messages or change tasks lists from the notification itself. Android 7.0 also introduced “bundled notifications” for when multiple messages are received.

what are push notifications? | Leanplum

Chapter 2: A Brief History of Push Notifications


Apple Push Notification Service (APNS) is launched with iOS 3.

In the early days, app users had to look for information or request it from apps through a website. Push notifications changed the way apps communicated with its users as app developers gained the ability to deliver messages to their users in a convenient, simple way. As a bonus, push notifications preserved battery life better than pull technology.

In the same year, Tapulous sends some of the first push notifications to its iOS app Tap Tap Revenge 2 through legacy mobile push service, Urban Airship.


Android Cloud to Device Messaging (C2DM) is launched by Google with Android 2.2

With Android 2.2, developers were able to send data from servers to their apps on Android phones. Before this critical update, only Google’s own apps could use push notifications to keep their data up-to-date. With C2DM, third-party developers were allowed this capability.


iOS 5 introduces the Notification Center.

Apple introduces the Notification Center in iOS 5, organizing iOS notifications into one place. Before iOS 5, push notifications would appear on the screen and pause current user activity. With this release, notifications popped up in a banner at the top of the screen and could be accessed in one place.


iOS 5 introduces the Google Cloud Messaging (GCM) replaces C2DM.

Announced at Google I/O, Google Cloud Messaging introduced the ability to send push notifications with deep-linking commands, app data, and iOS support.


Flash forward to 2016. Rich push notifications are introduced to iOS with iOS 10.

With this new rollout, app teams are able to customize the layout of their messages with media, customized text fields, and in-line reply options. Users can download this media directly from a rich push notification, without having to enter the app. And for the first time, apps can receive insights into whether users dismiss a push notification, helping them improve their mobile messaging strategy.

Firebase Cloud Messaging (FCM) succeeds GCM.

With Google’s FCM update, app developers have the ability to target clients in device groups and data messages up to 4KB.

Chapter 3: The Value of Push Notifications

You may be asking yourself, “what is the benefit of push notifications?” It’s a great question.

Push notifications create value for both users and mobile teams. The main benefits are increasing user engagement and app revenue. When executed correctly, an effective push notification strategy will drive conversions, while retaining more users. Let’s take a look at how this works.

Driving User Engagement

Low engagement doesn’t mean your app is disliked. Those who don’t find value in an app will likely fall dormant entirely or uninstall. Instead, there’s a chance that your app isn’t top-of-mind for some of your more casual users,meaning they aren’t in the habit of using it daily.
This is where push notifications come in. Push notifications drive engagement by keeping your app top-of-mind. By reaching your audience outside of the app, you can attract them back and re-engage them. Push notifications also serve as a useful communication channel to deliver transactional info, reminders and quick updates that are valued by users.

Driving App Retention

The average cost per install to acquire a new app user is $2. But as you’ll learn below, most of those users abandon the app. Here’s a quick rundown of the key facts covered in our retention report.

  • Mobile app retention is notoriously low — average day 90 retention is only 1.89 percent
  • The simple tactic of sending push notifications increases retention by 20 percent
  • Push notifications sent at personalized times can boost retention by 7x

Personalization is the key to push notifications. Personalized content and behavioral triggers were shown to increase message open rates, yet optimizes send times are a powerful strategy to improving your 90-day retention rates.

Push notifications can be a fleeting communication channel, especially on iOS. As explained earlier, iOS apps suffer from a lower push notification open rate because the OS clears messages once the user unlocks their phone. As a result, writing valuable content isn’t enough — the message must be delivered at the perfect time for the recipient to read it.

Personalizing push notification send times and leveraging behavioral triggers will ensure that your message reaches your audience at the right time. This has been proven to increase retention and lead to increased ROI.

Driving Revenue

Push notifications should be part of any app retention strategy because it translates directly into revenue. Push notifications aren’t just a matter of DAUs and the user experience — they can have a material impact on the bottom line. That’s because push notifications have been proven to help retention, and long-term users bring in more revenue over time.

For a specific example, we previously looked at how Target’s mobile app could earn an extra $209MM if it increased its retention through well-timed push notifications. The more you protect your acquisition investment, the more you drive ROI.

Do We Really Need Push Notifications?

It may be a common perception that push notifications are annoying or intrusive. Are push notifications really necessary? To evaluate, let’s imagine a world without push notifications.

In this scenario:

  • Messaging apps won’t be able to send conversation updates
  • News apps won’t be able to deliver breaking news, weather/traffic updates, and other time-sensitive information
  • Ridesharing apps wouldn’t be able to tell users when their driver arrive

In all of these examples, users lose value by missing out on time-sensitive information. Push notifications can provide great value, as long as they are not overused and the user’s personal preferences are nurtured.

Yes, we really do need push notifications. Some apps, like messaging services and rideshares, can’t function without them. The goal is to send notifications that provide value to the user rather than only providing value to the business.

Chapter 4: Push Notifications Best Practices

Recognize the Differences on iOS vs. Android 

After analyzing 1.5 billion push notifications, we found that Android is four times more powerful than iOS at engaging users via push notifications. You can see that iOS has an average open rate of 1.77 percent. Conversely, Android has an average open rate of 3.48 percent open rate — double that of iOS.

However, the median time it takes for users to interact with push notifications, depending on operating system, varies in an interesting way. iOS users open push notifications in a median time of seven minutes compared to Android users’ time of 48 minutes.

When it comes to your mobile strategy you should account for these differences. Since push notifications on iOS tend to be so ephemeral, it is smart to coordinate your push notifications with an email strategy, to extend reach to users who may not see or miss the push notification altogether.

Determine the Best Times to Send Push Notifications

It’s crucial to note when and where to send push notifications. Here, we break down engagement patterns according to region.

Although scheduling by time zone means you can respect typical day and sleep patterns, you’re not accounting for cultural differences that impact the way users engage with the app. For example, even if you schedule a notification at 3p.m. in a user’s local timezone, the user in that region might be busy at work and unable to check their phone. Instead, they may prefer to engage later at night, or after dinner. Sending at the wrong time will render the notification ineffective.

How do you solve this problem? We created a machine learning algorithm that analyzes individual app engagement patterns and automatically sends messages when people are most likely to open. By employing this tactic, you can improve the chances your push notifications will resonate with users, no matter where they are.

Increase Conversions With Personalization

The golden rule is that push notifications must be personal. Beyond that, push notification best practices depend on your app.

For apps with a lengthy onboarding process, personalized onboarding reminders may prove useful. Rather than sending a generic reminder to all users who fail to complete the onboarding, you can customize the content based on where the person is in the funnel. This allows you to present a more specific call to action.

Another example of an effective push notification is the shopping cart abandonment message. This long-standing issue in retail can be curtailed with personalized push notifications that remind users to complete their checkout. By reminding the person of which specific items were in their cart and creating a sense of urgency with promos, apps are more likely to see conversions.


Chapter 5: How Push Notifications Work 
on iOS & Android

How do push notifications work on Android? And how do push notifications work on iOS? Let’s break down some of the technical details. There are a few components essential in setting up push notifications for a mobile device.

Provider –> OSPNS –> Device –> Client App

The provider sends the push notification to the Operating System Push Notification Service (OSPNS), which routes app within the device. The majority of OSPNS are based on Google Cloud Messaging (GCM) and Apple Push Notification Service (APNS).


  1. Android device sends unique sender ID and app ID to the GCM server to register
  2. Once the ID’s are received, GCM sends a registration ID to that Android device
  3. That registration ID is then coded into the provider’s server
  4. The provider sends the push notification to the GCM server with the registration ID with the GCM server deliver the message to the corresponding device


  1. Apple requires iOS apps to request push notification permissions before they are allowed to be sent
  2. Once the user allows the app to send notifications, iOS requests a unique device token from the APNS server
  3. The app receives this token and sends it to provider’ server
  4. The provider then forwards the push notification request to APNS
  5. APNS then sends the push notification to the user device

For both iOS and Android apps, SDKs (software development kit) can be installed which tracks these tokens and allow for more flexibility when sending push notifications. With an SDK like Leanplum installed, a developer can track user behavior and send personalized push notifications with ease.


Chapter 6: Build a Push Notification Strategy for 
the Future

To future-proof your mobile app, you need to build a push notification strategy that will help you make the most of the coming years—and beyond.

Choose a Platform That Works for You

If you are still using Parse, this push notification vendor was scheduled to shut down in January 2017. Make sure your apps choose an alternative solution.

Create Rich Push Notifications

With iOS 10, videos and rich media are playable inside the push notification. According to Convince and Convert, “Audiences are 10x more likely to engage with video content — embed, share, or comment — more than text-only.” Consider adding videos with actionable replies to your rich push notifications for even higher engagement.

Combat Android Opt-Outs

For the first time, in Android 7.0 Nougat, users have the option to opt-out of push notifications. We predict that Android apps will now see the same challenges as iOS apps, and come up with more creative ways to convince users to opt-in.

To increase notification opt-ins, consider implementing Push Pre-Permissions. Push pre-permissions appear at the moment users are most engaged, explaining the value of push notifications. We’ve seen some concrete results, including a 182% increase increase in user opt-ins.

Ask for a demo today and 
learn how Leanplum can help you drive more app ROI.