End-user apps shipped simultaneously to the App Store and Google Play from a single React Native codebase, marketplace apps, content platforms, loyalty apps, service booking tools, and consumer products that need both iOS and Android coverage from day one. UI built with React Native's core components (View, Text, ScrollView, FlatList) and custom StyleSheet implementations that produce a polished, platform-appropriate look using React Navigation for stack, tab, and drawer navigation with platform-native gestures and transitions on each OS. Push notifications via Firebase Cloud Messaging (FCM) for cross-platform delivery with deep link routing so a notification taps into the correct app screen rather than the home screen, handled with @react-native-firebase/messaging and foreground/background/quit state handling on both platforms. In-app purchase integration using react-native-iap for App Store and Play Store subscription and one-time purchase flows including receipt validation via your backend to prevent receipt fraud. Biometric authentication (Face ID on iOS, fingerprint on Android) via react-native-biometrics for apps requiring fast re-authentication without password re-entry. App Store and Google Play submissions handled as part of the engagement: code signing configuration, provisioning profiles, build variants, screenshot and metadata preparation, and the review submission process, so your team does not need App Store Connect or Play Console expertise to ship. Target device coverage testing on a representative device set covering the top 10 iOS and Android device models by market share in your target geography before submission.