Android App Bundle: Distribution and Size Optimization
Article Summary
Dmytro Khmelenko breaks down how Android App Bundle reduced their app size by 20% without changing a single line of code. Here's how Google's 2018 feature actually works under the hood.
Instead of uploading multiple APKs for different device configurations, App Bundle lets you upload one file to Play Store. Google then generates optimized APKs tailored to each user's specific device configuration (locale, screen density, CPU architecture). Khmelenko uses bundletool to dissect exactly what gets delivered to users.
Key Takeaways
- App Bundle splits into master APK (12MB with code), locale APKs (54-104KB), and density APKs
- Screen density files vary dramatically: hdpi is 2.3MB, xxhdpi jumps to 6.2MB
- Users download only what they need: 19MB vs 24MB universal APK (20% reduction)
- Bundletool lets you extract and test exact APK combinations per device config
App Bundle automatically reduced download size from 24MB to 19MB by delivering only the resources each device actually needs.
About This Article
Freeletics had to manually manage multiple APK files in the Play Store console because their universal APK didn't account for different device configurations like CPU architecture, locale, and screen density.
Dmytro Khmelenko's team switched to Google's App Bundle format. They uploaded a single .aab file, and the Play Store automatically split it into optimized APKs using bundletool to handle device-specific configurations.
When they analyzed bundletool's output, they found locale files ranged from 54KB to 104KB and density files from 2.3MB to 6.2MB. This let them measure exactly which resources each device configuration actually needed.