Android App Bundle

Android App Bundle is a new universal format for publishing and distributing Android apps. Unlike the classic Android Package (.APK) format, AAB contains information about the device’s technical specifications and hardware. The app has the.AAB extension is smaller in size.

What is the Android App Bundle for?

Since August 2021, developers have been required to use the Android App Bundle when publishing mobile apps on Google Play. The following format is also required:

• to reduce the size of the application;
• flexible distribution settings;
• convenience of supporting multiple versions, for example, those intended for different devices;
• easy management of published applications and viewing statistics;
• simplifying the release of new versions, such as game updates.

What’s the difference between AAB and APK?

APK apps have several different versions. This can be seen, for example, by visiting the popular alternative app site APKMirror.

Each version is built as a “monolith” and contains all the resources for various devices and configurations. AAB delivers only the resources and configurations required for a specific device.

An Android App Bundle is a package of various components, similar to a ZIP archive. It contains all the files needed for installation. A single.AAB file can replace multiple APK versions because it extracts the app versions for the required devices and OS versions when unpacked.

An APK may include support for different screen resolutions or languages. If the user doesn’t need them, they’ll just take up space. AAB installs a “split” APK for a specific configuration and doesn’t take up any memory.

How AAB works

When a user downloads an app published in AAB format, Google Play automatically generates a small APK from the package with parameters optimized for a specific device. These APKs are called split APKs: they are lighter than standard ones, but less functional. If the user decides to change system settings, such as changing the language, the system will generate and download a new split APK for the new device configuration.

Features of AAB

Light weight

An.AAB app takes up, on average, 15% less space than an APK app. This helps conserve network and device resources when downloading and installing apps, improving the user experience. For developers, this means more downloads: smaller apps are more likely to be downloaded.

Convenient control

With App Bundle Explorer, developers can easily update their app, roll back to an older version, or make adjustments to the entire bundle in one go. Advanced settings allow you to view statistics, metadata, and other information that helps promote your product.

Strong connection with Google Play

AAB further ties Android app releases to the Google Play Store. Without the store, working with packages is virtually impossible: AAB requires specialized software for unpacking and installation. The Android App Bundle code is free and open-source, so developers can write their own software, but this requires significant resources.

Transfer of responsibility for security

With an APK, the app’s security is the responsibility of its developer. They alone own the digital certificate that allows modification of the program’s code. AAB moves APK creation to Google Play Cloud Services. Apps are also signed there. Therefore, responsibility for security shifts to Google. Developers can keep a copy of the certificate.