There is always a lot on Android’s agenda. Not only the eagerness of creating new technology and ways of challenging the digital world, but a devoted attitude to solve the most painful setbacks. Specifically within the mobile apps and games realm.

Creating a good app or game is not the ultimate truth. Developers need to account for many circumstances towards success. And one of them is indeed the entire user’s journey. Especially the download experience (APKs), which developers have been long dwelling upon.

Android’s answer? Android App Bundles (AAB). Maybe this already rings a bell for you. And that’s what this article is all about: to provide you a deeper understanding about Android App Bundles and out of all the noise around the topic if you should indeed embrace it.

But what are exactly Android App Bundles?

Android App Bundles were launched way back in 2018 committed to brushing up the download experience of apps by Android users. Some of its main features are:

  • Download only the app resources that are required by the user’s device (e.g. why as a smartphone user would you download the images and videos with a format that is only applicable to tablets?).
  • Download additional features only if they are needed (e.g. why as a user would you download 30 different languages if you are only going to use one?).
Android App Bundles vs Universal APK

Google states that the AAB format provides an APK reduction of up to 50% when compared with the regular one. For example, the popular apps Netflix and Duolingo that adopted the new AAB format claim to save respectively 30% and 42% of download apps’ size. 

AAB Advantages and Disadvantages for the users

According to Google, the Android end-users get the most out of the AAB format. Specifically a faster and smoother download and install journey. Mainly:

  • A smaller app size means saving storage in the device.
  • Requiring less storage means that the user can have more apps on their phones.
  • Additionally, the download and install times will be faster.
  • Consequently, the user will save on mobile data usage (if not on WiFi).

But AAB was not a bed of roses. And it came with some inconveniences:

  • The complexity of the installation process. The user no longer can directly download and install a single APK file because of the complexity and quantity required by the files.
  • Directed to power users.

AAB Advantages and Disadvantages for the developers

But what’s the developers’ pay-off? 

  • A smaller app size will translate into higher installation rates.
  • A smaller uninstall rate since it’s taking less space on the user’s phone.

And the main constraints?

  • Additional complexity with additional code and split files.
  • Developer needs to share its private app signing key to Google Play (developers can no longer sign their own apps).
  • Negative impact on user reach via alternative app stores (which we cover in the last section).

Android App Bundles in practice (Aptoide as an example)

Aptoide – our leading-edge partner app store, with more than 100 million users, has been supporting AAB since 2019, one of the first-ever third-party app stores to do so.

Here are some examples of apps that use the AAB format and are available today to be downloaded on Aptoide:

Android App Bundles examples

That is the reason why, when you go to the upload app screen in the Catappult developer console, you see an option to upload the split files (as shown in the screenshot).

Android App Bundles | Files Uploader

Does this mean that once you upload the app in AAB format it reaches all the full potential distribution power of Catappult? No, it’s not necessarily the answer and we will tell you why.

Should you, as a developer, adopt the AAB format?

By the end of 2021, the AAB format was already adopted by 28% of developers in Google Play (vs. 15% in 2020). The most popular type of AAB is the simplest format, with 96% of the apps adopting it, while PAD and PFD represent only 4%.

Even though the adoption of the AAB format in Google Play has been increasing, the Catappult team believes it’s not the only way to go. There are many other aspects you need to account for, mainly your goals and target. There’s a world beyond Google, with plenty of users and potential. Yes, we’re talking about the alternative app stores. Which can provide massive potential reach for your app.

Although some of Catappult’s partner app stores do support the AAB format (e.g. Aptoide), many of them still do not (e.g. Xiaomi, VIVO, OPPO, Meizu, Softonic). By not considering those stores you could be missing out on an opportunity to reach a bigger user base.

To give an idea, when we take a look at the download reach of our Top 20 apps, not a single one is using the AAB format when publishing their app in Catappult, some of them being Lords Mobile, Mobile Legends, and Clash of Kings.

As a final and important note, although we support progress, continuous innovation and we are eager to support all distribution formats if we focus on the success of a worldwide user reach, our data show that AAB is not the only path.


Check out our website to learn more and join Catappult today.