As a developer, it's up to you to do everything in your power to improve user retention. Keeping the install-to-uninstall ratio as low as possible is important for your app to be ranked highly. New users are joining the Android ecosystem by the millions each year as Google continues expanding into markets such as India and various African nations. The users in these emerging markets tend to be more data-conscientious than most, so you may not even realize that your APK size has become too large to appeal to these users. That's why Google is introducing a new app model for Android called the Android App Bundle. Coupled with the new Google Play Dynamic Delivery, app sizes can be dramatically reduced to help improve user retention in key markets.

Reducing APK size with Android App Bundle and Google Play Dynamic Delivery

If you are building an app with the aim to provide the most compatibility with Android devices, that means you'll need to build for all form factors including Android smartphones, tablets, and Chromebooks and all hardware architecture including ARM, ARM64, and x86. You'll also need to create multiple layouts to accommodate the diversity of screen resolutions, aspect ratios, and densities. And to give the best experience for users in different regions, you'll also need to translate your app into multiple languages. Putting all of this together can result in one massive, bloated APK that contains a lot of resources that aren't relevant to most users. Of course, you can offer different APKs for each architecture, form factor, layout, etc. and let Google Play handle which version to serve the user, but you'll still end up with users installing apps that contain unnecessary resources.

With the new app model called Android App Bundle, you can go ahead and bundle everything your app needs for every device. Just upload your app to the Google Play Developer Console and hit "create bundle." It's that simple! Then, thanks to Google Play Dynamic Delivery, only the resources and code relevant to the user's particular device will be served. For example, if a user whose primary language is French downloads your app that has designated French language strings, then Dynamic Delivery will serve the French translation and not an APK that contains all the languages. This can potentially dramatically reduce the overall download and installation size. We were told that LinkedIn saw a 23% reduction in app size while Twitter saw a 35% reduction.

The Android App Bundle is also modular so you can deliver features on-demand instead of during installation. This requires that you join the beta for Google Play Dynamic Delivery and download the latest Android Studio 3.2 Canary release to publish your app on the Google Play Store. The amount of data that you'll save with App Bundle and Dynamic Delivery will depend on the number of app variants you offer and the kinds of resources you bundle with your app, but given how easy Google is making it for developers to reduce APK size, you should take advantage of the new tools as soon as possible if you want to draw in more users from emerging markets.