AAB vs APK: What Google Play Needs and Why
AAB vs APK: why new Google Play apps must use App Bundles since August 2021, how Play builds optimised APKs, the 4 GB limit, and when APKs still matter.
Short answer
An APK is an installable Android package. An AAB (Android App Bundle) is a publishing format: you upload it, and Google Play builds optimised APKs for each device. Google says new apps have had to publish with App Bundles since August 2021, and the total compressed download for an install must be no more than 4 GB.
The difference
| APK | AAB | |
|---|---|---|
| What it is | The file a device installs | A bundle Google Play turns into APKs |
| Can users install it directly | Yes (sideloading) | No |
| Required for new Play apps | No | Yes, since August 2021 (Google) |
| Download size for users | Everything for every device | Only code and resources each device needs |
| Signing | You sign the APK | You sign with an upload key; Play signs APKs with the app signing key |
Why Google moved to bundles
Google says Play uses your bundle to generate and serve optimised APKs for each device configuration, so users download only what they need. You no longer build and manage multiple APKs per device type.
Size limits
Google’s docs say the total compressed size of the APKs needed to install your app (base plus configuration APKs) must be no more than 4 GB, and on-demand feature modules must also meet that limit. Asset packs have separate limits. For large games, see Play Asset Delivery.
When you still need APKs
- Sideloading a build to a device for testing (use bundletool to produce APKs from your bundle).
- Other stores that accept APKs.
- Internal app sharing accepts both.
Signing and Play App Signing
With bundles, Google holds the app signing key and you keep an upload key. If you lose the upload key, you can request a reset. See lost upload key.
How to build an AAB
- Android Studio: generate a signed bundle
- Flutter: flutter build appbundle
- Unity: tick Build App Bundle (Unity guide)
Frequently asked questions
Can I convert an AAB to an APK?
Yes, with Google’s bundletool, which generates APKs from a bundle for local testing.
Does an AAB make my app smaller for users?
Usually yes. Play serves only the code and resources each device needs.
Are AABs required for updates to old apps?
Google’s requirement covers new apps (since August 2021) and TV apps (since June 2023). Older apps can check their status in Play Console.
Sources and how we keep this accurate
Policy facts are checked against Google's own documentation on the date shown above. Google can change requirements at any time, so confirm in your Play Console. Where we give advice or estimates rather than Google's rules, we say so. TestersZone is independent and not affiliated with Google. Drafts are AI-assisted and reviewed by our team.
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