What is AAB? Why is Google Play Store moving to AAB, how different is it from APK? Read

Google is bringing a big change to how applications will be published on its Android app store. From August 2021, new applications being published on the platform will be in AAB format, which stands for Android App Bundles. Google's plans to implement the Android App Bundle date back to 2018, when the Alphabet-owned company first talked about them. For questions like what is AAB, and why Google Play Store is moving towards AAB, find answers below. 

What is AAB?

Google is doing away with APK files, with a plan to gradually switch from APK to AAB. But what is AAB? As mentioned earlier, AAB stands for Android App bundle. According to Android Developer's guide, an Android App Bundle is a publishing format that includes all the resources and compiled code for an application, and defers the APK generation and signing to Google Play. AAB formats allow custom downloads for devices that request an application. More about why Google Play Store is moving to AAB in the next section.  

Using Android App Bundles, Google Play will be able to optimize APK distribution for specific device configuration and language. In other words, when a user will on the 'Install' button on the Google Play Store, the file downloaded will be tailor-made for his or her device. For instance, if users have selected English as a language on their device, they do not require the language pack for German or French and hence they would not be downloaded. Similarly, if a device requesting an application does not support 4K resolution, the APK received by the device will not have the 4K resource pack.

Why google play store is moving to AAB?

Google is switching to AAB as it allows the platform to deliver customized solutions to the users, based upon device configurations and languages. The removal of unnecessary resource packs from a universal APK will reduce the download size by up to 15%, saving Google a lot of bandwidth. Subsequently, files that are smaller in size will take less time to download and hence reducing the chances of users cancelling the download request. More about how to convert AAB to APK in the next section.

AAB will also provide Google with more control over app distribution services, as any third party store will have to set up an AAB to APK converter over cloud in order to provide the applications available on the Google Play Store, while Google does it with the help of its own tool called 'bundletool'. Another question that might arise at this point: "is AAB better than APK?" Essentially, AAB enables app distribution platforms like Google Play Store to provide custom applications to Android, which do not contain the codes and resource files that are not required. 

How to convert AAB to APK?

Once developers start uploading AAB files to Google Play Store, Google will make use of its 'bundletool' to convert those files to APK format and send it to devices. These APKs will not contain all the files that might be present in a universal APK but have files that are necessary to run an application on a specific device. It is also available as a command-line tool for developers so that they can create a server compatible build of their application's APK.