Mobile apps

Building an Android app (APK and AAB)

Before you start

Connect GitHub and link a repository (Code tab → GitHub). Publish your site — the app loads it, so an unreachable URL fails the build's preflight check immediately rather than after fifteen minutes of compiling.

Building

Go to Mobile app → Build and choose:

Android APK — debug-signed. Install it directly on a phone to test. No certificates needed.
Android AAB — the production bundle the Play Store requires. Needs signing secrets (below).

A build takes roughly 10–20 minutes. It appears in the list below the buttons with live status; when it turns green, press Get files to download.

Installing the APK to test

Download it, transfer it to an Android phone, and open it. Android will ask you to allow installation from unknown sources — expected for a debug build.

Signing for the Play Store

Generate a keystore once and keep it safe forever — losing it means you can never update your app again.

keytool -genkey -v -keystore release.keystore -alias myapp \
  -keyalg RSA -keysize 2048 -validity 10000

# then base64 it:
base64 -i release.keystore | pbcopy      # macOS
base64 -w0 release.keystore              # Linux

Add two repository secrets on GitHub (Settings → Secrets and variables → Actions):

ANDROID_KEYSTORE_BASE64 — the base64 output above
ANDROID_KEYSTORE_PASSWORD — the password you chose

Build again and the signed release APK and AAB appear alongside the debug one. Without the secrets the build still succeeds — it simply skips those outputs.

Costs

Google Play Console: $25, once.