What’s the difference between APK and AAB?

HIGHLIGHTS

  • Google to replace Android APK with AAB
  • Google has now announced that all apps will now be switched to this AAB file format
  • Target API level 30 (Android 11) or above and adjust for behavioral changes.

Google is mandating that Devs need to submit new apps in the AAB format on the Play Store. that it will be replacing the Android Package (APK) with the Android App Bundle (AAB) for all new apps which will be published on Google Play starting August 2021 and to replace APK as the standard publishing format entirely on Play Store.

AAB format was actually introduced in 2018, AAB is essentially a more advanced application packaging method, mainly to solve the problem that developers need to create applications of different architectures, and intelligently match the user’s device model for distribution, thereby simplifying the size of the APP installation package.

At present more than a million apps on the Play Store, including Adobe, Netflix, Twitter, and Duolingo, use app bundles instead of APKs, the company claims. In addition, the company will make it the standard for all app developers to submit to the Play Store in the newer AAB format from August 2021.

App bundles are publishing format, whereas APK is the packaging format that eventually will be installed on the device. Google uses an app bundle to generate and serve optimized APKs for each user’s device configuration, so they download only the code and resources they need to run your app. so end-users can get well-optimized applications with reduced app size.

Android Application Package (APK)

APKs are a type of file that is recognized only by an AOSP. An APK file basically contains all the necessary app resources needed to install an app on any android platform.

It is not wrong to think of APK files as essentially compressed zip files. They contain all the app files and code in their compressed form. In addition, APK files also contain an app certificate which helps with app recognition on the Google Play Store.

This compressed app file can only be extracted on an Android system. Expect Andriod platform recently other operating systems such as HarmonyOS & Windows 11 were able to open and install an APK file.

One of the best things about android was sideloading applications with a single click any users were able to download and install APK files from other app stores other than the Google Play Store.

Android Application Bundles (AAB)

AABs were added in 2018 to the Android system. This is now the official app format to be used on the Google Play Store. There are several reasons AABs are preferred over APKs now.

as per Google, There are now over 1 million apps using app bundles in production, including the majority of the top 1,000 apps and games on Google Play such as Adobe, Duolingo, Gameloft, Netflix, redBus, Riafy, and Twitter.

According to official Android documentation, AABs are an app publishing format that contains all the necessary app files and codes. However, they hand over the process of APK generation and signing in to the Play Store.

Here’s a visual representation of the contents of a typical AAB file –

SourceAndroid documentation 

Advantages of AAB format

  • Reduced App size: Google Play uses the app bundle to generate and optimize APKs for distribution for different device configurations and languages. This makes your app smaller (on average, 15% smaller than a universal APK) and faster to download, which can lead to more installs and fewer uninstalls.
  • Play App Signing: Play App Signing, which is required for app bundles, protects your app signing key from loss by using Google’s secure infrastructure and offers the option of upgrading to a new, cryptographically stronger app signing key.
  • Play Feature Delivery: Used by more than 10% of the top apps using app bundles, Play Feature Delivery gives you the ability to customize what feature modules are delivered to which device and when, with install-time, conditional, and on-demand delivery modes.
  • Play Asset Delivery: Reduces user waiting time by dynamically delivering large assets while cutting delivery costs. Games using Play Asset Delivery can use texture compression format targeting, so your users only get the assets suitable for their device, with no wasted space or bandwidth.

Source: Android Developers Blog

Disadvantages of AAB format

  • sideloadeding apps—that is, apps that are not installed using the Google Play Store and are missing one or more required split APKs—fail on all Google-certified devices and devices running Android 10 (API level 29) or higher. When downloading your app through the Google Play Store, Google ensures that all required components of the app are installed.
  • Android App Bundles do not support APK expansion (*.obb) files, so you may not be able to sideload gaming applications.
  •  if you install an app from the Play Store but want to update to the latest version from another Play Store alternative such as Amazon App Store app gallery or Aptoide Store), then the installation might fail due to a signature mismatch.

How to sideload AAB application in android platform

After downloading the App bundle application, you can sideload using some 3rd party applications such as app bundle installer & Split APKs Installer (SAI)Android’s package installer currently does not support AAB packaging format, which means the user won’t be able to sideload with one click.

Step 1: download AAB application from trusted sources or official websites

Step 2: Download SAI or split apk installer from playstore

Step 3: At the bottom of the Application page. You can now use the internal file picker or system file picker to select the Android App Bundle you want to install.

Step 4: Navigate to the downloaded app and click install and wait till receiving a pop-up notification as soon as the installation is complete.

Let me know in the comments if you have any trouble installing .AAB file

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