To install an APK on Android, open the downloaded file, allow your browser or file manager to 'install unknown apps' when prompted, and tap Install. If you see 'App not installed', the usual cause is an existing app with the same package name signed by a different key, or a version code lower than the installed one — uninstall the old version or raise the version code.
Installing (sideloading)
- Download the APK on the phone — from the builder app, or send it to yourself.
- Tap the file. Android asks to allow the source (Chrome, Files) to install unknown apps; allow it for that source.
- Tap Install. Play Protect may scan the app; for a new, unknown package it can show a warning — choose Install anyway for your own app.
"App not installed" — decoded
| Cause | Fix |
|---|---|
| Same package already installed, different signing key | Uninstall the old app first (its data is lost) |
| Version code lower than the installed one | Rebuild with a higher version code |
| Not enough storage | Free space; installs need ~2–3× the APK size |
| Download incomplete or corrupted | Download again |
| Android older than 7.0 | Not supported |
The 15-minute test script
- Home screen: icon is crisp, name not truncated.
- Cold start: force-stop, launch. Splash, then first screen, no white flash.
- Every screen: navigate everything; back goes back and exits only from the first screen.
- Rotation and keyboard: rotate on each screen; open the keyboard on each form — nothing hidden behind it.
- Offline: airplane mode, cold start, every screen again.
- Permissions: accept once; reinstall and deny once. The page must handle both.
- Links: external, tel:, mailto: and target="_blank" behave as intended.
- Update: install the next build over this one; saved data is still there.
- Cheap phone: repeat the essentials on the oldest device you can borrow.
Sharing test builds
For a few testers, sending the APK works. For more — and required before production for new Play accounts — use Play's internal or closed testing tracks: testers install from the Play Store, updates arrive automatically, and you get crash reports.
Questions people ask
Is it safe to install an APK from outside the Play Store?
It is safe for an app you built yourself. Allow unknown sources only for the app you are installing from, and only install APKs whose origin you trust.
Why does Play Protect warn about my APK?
New packages that Play has never seen can trigger a warning. For your own app, choose Install anyway; once published on Play, the warning stops.
Will updating the APK delete my app's data?
No — installing a new version with the same package name and signing key keeps localStorage and IndexedDB. Uninstalling first deletes them.