FitSnacks is a native mobile application engineered with React Native and Expo, with a strong focus on runtime performance, privacy-aware data handling, and resilient offline behavior.

The core architecture is built on strict TypeScript and a modular domain-oriented structure (components, services, store, and models) to keep boundaries explicit and refactors safe as features scale. Global client state is handled with Zustand, while persistence is powered by react-native-mmkv for low-latency reads/writes on device.

The UI layer combines React Navigation (stack + tabs), FlashList for high-throughput list rendering, Reanimated for smooth interactions, and Expo modules for haptics and notifications. Health capabilities are integrated through HealthKit and Health Connect using react-native-health, react-native-health-connect, and expo-health-connect, with additional iOS widget support via @_rkstar/react-native-widget-center and @bacons/apple-targets.

Engineering quality is enforced with Jest and Testing Library across units and critical services, and native reproducibility is managed with Expo prebuild plus expo-build-properties. Delivery is automated through EAS Build and EAS Submit, while Expo Updates enables OTA releases for fast iteration without requiring a full store release for every change.

• Strict TypeScript + modular domain architecture for scalable maintenance

• Zustand global state with MMKV persistence for fast on-device data access

• Performance-focused UI stack: FlashList, Reanimated, and Expo native modules

• Deep health integrations: HealthKit/Health Connect and iOS widgets

• Robust delivery pipeline: Expo prebuild, EAS Build/Submit, and OTA updates