Traditionally, Android apps were available in APK format and at the end of the story, but that all started to change with the arrival of Android App Bundle and various additional extensions like APKM, XAPK or ZIP files with multiple APKs.
Android App Bundles is the official format for publishing apps on Google Play, although it is a bit more mysterious than the APK of a lifetime. Here we will see What is an Android app bundle, what are their advantages and how do they differ APKs.
What is an Android Application Bundle (.aab)
Android app bundles are nothing new. Google introduced them to us at Google I / O 2018 as a new publishing format that would allow reduce the size of downloads for users which, according to Google studies, translates into more downloads and fewer uninstalls.
Essentially, an App Bundle contains all the resources of an application, although it cannot be installed directly on the mobile. In other words, the base and the rest of the recursor are included because they are graphics, layouts
With so much going on inside, there’s a question that arises: How come one of the advantages of the App Bundle is that they take up less? The answer is that the bundle of apps that a developer creates takes more than an APK. The smallest size is in the APK download which reaches the users and that Google Play generates from said set of applications.
It looks a bit like a tongue twister, but it’s actually a lot easier than it looks. If a developer creates an app and publishes it in APK format, the normal thing is that all resources are included like, for example, graphics in the 30 languages supported by the application. For simplicity, if each graph is 100KB, we will have 3000KB in said APK.
An App Bundle in .AAB format includes absolutely everything, but Google’s servers analyze its content and generate APK files with all possible configurations and that they only include resources for that configuration. In other words, the user downloads an APK which, instead of having the graphics for 30 languages, only includes those configured on the mobile. Instead of 3000 KB, it is 100 or 200 KB.
With the App Bundle, Google can generate APKs that only include the resources of your mobile. In other words, smaller
What if the user later changes the language of the mobile? Fortunately, everything is planned. In that case, Google Play downloads additional language files from your store. The same goes for the optional modular features that are included in the app and can be downloaded later, not included in the initial download.
As can be seen, the reduction in download size is the main advantage of this format over traditional APK publishing, although not the only advantage. In the past, Google has highlighted the 16 compelling reasons for developers to use the App Bundle instead of the APK: less development time, more information in the Google Play console, longer build times. short, modular functions …
How is an APK different from a set of apps?
So far, we’ve talked a lot about bundles from an app developer’s perspective, but as a user, how is one different from the other? In truth, the question is delicate, because as a user you shouldn’t come across bundles: is a package allowing developers to publish their applications on Google Play. As a user, there isn’t much you can do with it, at least not without the tools and knowledge.
And yet we find them in a specific case: when we want to install apps outside of Google Play, and they are not available in a lifetime APK file, but in a bundle of apps. They are more and more common on sites like APKMirror or APK.Support. What we’re downloading here isn’t really an original set of apps, but a collection of APKs that Google has generated for the various setups.
In other words, while apps published with APK are a single APK, those published as an App Bundle have a base APK and multiple APKs for different configurations, called Split APK. This made life difficult for websites to download Android apps, which had to create alternatives like APKM of APKMirror or XAPK, on UpToDown and other sites.
APKM, XAPK and other formats are ZIP files containing APK string which must be installed at the same time
APKM, XAPK or ZIP file filled with APK is not an app bundle, although this is a side effect of them. This is all a ZIP file that includes the base APK and secondary APKs for the supported architectures, languages, or any other available variations. They cannot be installed by themselves, just like an APK, but a special installer application is required that can install the “songs” together.
In other words, App Bundle replaces the APK when publishing an app to Google Play, but not when installing it. APK files continue to be installed on the mobile, but not one, but several and understanding only what is necessary for it to work on your mobile.
Along with the set of apps that the developer downloads, Google generates countless custom APKs that make downloading the apps faster. App Bundle and APK are not opposites, but complementary. This is a good invention, although it undeniably makes it difficult to install apps from external sources.