Designed, built, and operate a real-time multiplayer card game across Android, iOS, and Web. Architected a hybrid backend combining Firebase serverless functions for transactional workflows with a dedicated Node.js server for low-latency real-time game state synchronization. Implemented production-grade state synchronization to maintain consistent gameplay across concurrent users. Designed in-app economy systems (coins, streaks, referrals, leaderboards) to drive engagement and retention. Integrated AdMob mediation for monetization and instrumented analytics using Mixpanel to optimize funnels and user behavior. Manage releases, crash monitoring, and performance optimizations independently in a live production environment.