Danylo Davydenko

Built cross-platform mobile apps for international clients (Cene+, Jerry, Tanglio), owning feature delivery end-to-end. Implemented real-time seat-selection using Supabase Realtime (Broadcast/Presence) alongside atomic PostgreSQL RPC locking to prevent conflicts. Designed monetization flows integrating payments with Stripe PaymentSheet (Apple Pay/Google Pay/3D Secure) and processed 1,000+ transactions across production apps. Improved mobile performance by migrating feeds to Shopify FlashList with custom recycling and memoization to maintain 60 FPS on low-end Android. Used TanStack Query and Zustand with optimistic mutations, rollback, and deduplication to reduce redundant API calls by ~40%. Established automated cross-platform CI/CD and E2E testing using Maestro, and implemented comprehensive Supabase backend infrastructure with multiple tables, RPCs, triggers, and RLS enforcement.

Worked on cross-platform mobile apps for international clients (Cene+, Jerry, Tanglio). Architected real-time seat-selection using Supabase Realtime and atomic PostgreSQL RPC locking. Engineered monetization flows integrating RevenueCat, Stripe PaymentSheet (Apple Pay, Google Pay, 3D Secure), processing 1,000+ production transactions across three apps. Built client-side state with TanStack Query and Zustand, using optimistic mutations with rollback and query deduplication (~40% fewer redundant API calls). Eliminated scroll lag on low-end Android by migrating list feeds to Shopify FlashList with custom recycling and memoization, maintaining 60 FPS over 1,000+ item feeds. Automated cross-platform CI/CD with EAS and established E2E suites with Maestro. Designed Supabase backend infrastructure including 15+ PostgreSQL tables, 10 optimized RPCs, database triggers, and enforced RLS across 20+ Row-Level policies.

Developed an enterprise B2B offline-first mobile system for field logistics and distribution (Boolean Distribution). Implemented a fault-tolerant offline architecture using SQLite plus a persistent background mutation queue with exponential backoff and conflict resolution to ensure zero data loss through offline-to-online sync. Added battery-friendly GPS throttling and geofencing logic to reduce battery usage by ~25%. Built multi-step inspection and ordering wizards, improving completion steps by ~50% before background upload. Implemented refresh/interceptor logic for reliable silent updates and graceful failure recovery.