Solo-built and published cross-platform (iOS/Android/Web) educational app for preschoolers on React Native + Expo, live on Google Play under the Families program. Built a custom COPPA-compliant analytics system from scratch with zero PII/device-identifier collection, and authored the app's privacy policy. Designed a persistent game-state architecture (React Context + AsyncStorage) with debounced writes and crash-safe resumability, plus a literacy-based parental gate. Bilingual (EN/ES) content across 18 animals.