OneSignal

1. Create an app at OneSignal.
2. Upload your APNs key (iOS) and Firebase Cloud Messaging credentials (Android).
3. Copy the OneSignal App ID.

In .env.local:

EXPO_PUBLIC_ONESIGNAL_APP_ID=your-app-id

In src/config/features.ts:

oneSignal: true,

The Expo plugin is already in app.json (onesignal-expo-plugin, production mode). After changing the App ID, run npm run prebuild.

Init lives in src/lib/onesignal.ts. Permission is requested from src/app/index.tsx on first launch. After login, the Firebase UID is typically set as the OneSignal external user id so you can target signed-in users.