APK and AAB

Every successful Android build produces two files. They are the same app — the APK is repacked from the bundle — and which you want depends on who is installing it.

An iOS build produces one file instead, an .ipa, which nobody installs by hand: it goes to TestFlight. See How iOS builds work.

Which to use

	.apk	.aab
Full name	Android Package	Android App Bundle
Install directly on a phone	Yes	No
Upload to Google Play	No	Yes
Send to a tester	Yes	No
Contains every screen density and architecture	Yes	Yes, split by the store on delivery
Size	Larger	Smaller as delivered, because Play sends each device only what it needs

Use the APK to put the app on a phone yourself, to share with your team, or to hand to members directly.

Use the AAB for Google Play. Play has not accepted APK uploads for new apps since 2021.

Installing the APK

1. Transfer it to the phone — email, cloud drive or USB.
2. Open it on the device.
3. Allow installs from that source when Android asks.
4. Open the app.

Android warns about apps that did not come from Play. That warning is about the source, not the app, and it is expected for a build you compiled and installed yourself.

Before you plan an AAB upload

Whether the .aab is uploadable depends on what signed it. With no upload key set up, your build is signed for testing — installable on any phone, refused by Play. See Android signing and the Play Store.

When it does not work

Symptom	Cause	Fix
The phone will not open the .aab	App bundles are not installable files	Download the .apk instead
App not installed on an older device	An earlier build with a different signature is already installed	Uninstall the old one first
Play rejects the upload as debug-signed	That build was signed for testing, not with your upload key	Android signing
The APK installs but shows a white screen	The app cannot reach your site	Confirm the site is public and serving over HTTPS