AAB (Android App Bundle)
Also known as: android app bundle, aab file, aab vs apk
An AAB (Android App Bundle) is the publishing format developers upload to Google Play. Play uses it to generate and deliver device-specific APKs, so each phone downloads only the code and resources it needs rather than one large universal package.
- Publishing format uploaded to Google Play
- Play generates device-specific APKs from it
- Reduces download and install size per device
AAB vs APK
An AAB is a build-and-upload format, not something you install directly. It packages all of an app’s code and resources for every device configuration. When a user installs from the Play Store, Google’s servers split the bundle and deliver a tailored set of APKs to that specific phone.
The payoff is smaller downloads: a device pulls only the screen densities, CPU architecture, and language resources it actually uses, instead of the entire app for all configurations.
Why it matters for storage
Because Play delivers only the relevant slices, installed apps take less space than a one-size-fits-all APK would. This is conceptually similar to app thinning on iOS, where the store tailors the download to each device.
AAB is now the required publishing format for new apps on Google Play, so most modern installs already benefit from this targeting.