Difference between apk (.apk) and app bundle (.aab)

App Bundles are a publishing format, whereas APK (Android application PacKage) is the packaging format which eventually will be installed on device.

App Bundles use bundletool to create a set of APK. (.apks) This can be extracted and the base and configuration splits as well as potential dynamic feature modules can be deployed to a device.

The dependencies can look something like this:

The contents of an App Bundle look kind of like this:

More information on App Bundles is available here.

App bundles are publishing format, whereas APK (Android application Package) is the packaging format which eventually will be installed on device.

Google uses app bundle to generate and serve optimized APKs for each user’s device configuration, so they download only the code and resources they need to run your app. Therefore, users can get smaller and more optimized downloads.