How to Modify and Sign App Bundle (.aab) Files
Updated on / dernière mise à jour : 02/17/2023
Google's app bundle files
An AAB file is an Android App Bundle, a file format developed by Google to streamline the process of delivering Android apps. It is essentially a zip file that contains all the code and assets needed to install an Android app on a user's device.
Historically, Android apps were distributed as APK (Android Package) files. These files contained everything needed to install an app on a device, including code, resources and assets. However, APKs had some drawbacks, including large file sizes and difficulty in supporting different device configurations. This made it challenging for developers to deliver apps efficiently and for users to install them quickly and easily.
To address these issues, Google developed the AAB format in 2018. The AAB format allows developers to create a single bundle that contains all the code and resources needed to run an app on a user's device. The bundle can be tailored to the user's specific device, including language, screen resolution and other settings. This results in smaller download sizes and faster installation times.
The AAB format achieves this by using a technique called "Dynamic Delivery." Essentially, the bundle contains only the code and resources needed to run the app on the user's device. When a user installs the app, the Google Play Store will dynamically download and install any additional resources that are needed, based on the user's device configuration. This ensures that users get the best possible experience, while minimizing the amount of data they need to download.
AABs are used by developers to publish apps on the Google Play Store. When a developer uploads an app to the Play Store, they upload an AAB instead of an APK. The Play Store will then use Dynamic Delivery to generate and serve optimized APKs to users based on their device configuration. This helps to ensure that users get a high-quality app experience, regardless of their device.
Are APK files still used?
Amazon does not use AAB files to distribute Android apps. Instead, they use the traditional APK format, which has been the standard format for Android apps for many years. While the AAB format was developed by Google to address some of the limitations of APKs, it is currently only supported on the Google Play Store. Other app stores, including the Amazon Appstore, continue to use the APK format for distributing Android apps.
Amazon has its own submission and review process for Android apps that are published on the Amazon Appstore. Developers must follow specific guidelines and requirements when submitting their APK files to Amazon, such as ensuring that the app is compatible with Amazon's devices and meets their quality standards. Once an app is approved by Amazon, it is made available for users to download and install through the Amazon Appstore.
SOLUTION: steps to modify and sign an App Bundle (.aab) file
1 – Build your Android App with your App creation platform (i.e.: MIT's App Inventor 2) and download the .apk file, as well as your keystore, to your PC.
2 – Modify your .apk file if needed. To do so, you can read our article "How to overcome MIT App inventor's 5 meg limit for your apk files?" (only need to read elements 1 to 7). You will probably want to modify the AndroidManifest.xml file within your .apk and this procedure will allow you to do so…
3- Now you can read Shreya.ig's excellent article "Edit or Modify the AAB file – change API 29 to 30 android 11" (important: follow the "easy method – short"). This shall allow you to convert your .apk file into an .aab file.
4- Once done, read Tomer Shami's very interesting "Tutorial for signing an AAB file".
5- And there you go, you've now modified an .apk file, converted it to an App Bundle file (.aab) and signed it. You are now ready to export it to the Google Play console.
Robert Radford, M.A.