• Architected core platform modules for gym management system, designed normalized schema with proper foreign key constraints and composite indexes at 99.7% uptime • Built BigQuery streaming pipeline with batched inserts and partitioned tables by event date, reduced log processing overhead by 60% handling 100K+ events daily without scan costs blowing up • Integrated 3+ third-party services behind adapter pattern with circuit breakers, automated 85% of workflows through webhook handlers saving 20+ hours weekly in manual ops • Shipped 8 feature overhauls with API versioning strategy — v1/v2/v3 routes coexisting, request transformers ensuring 100% backward compatibility for legacy mobile clients • Reverse-engineered biometric device protocol over TCP, built custom driver parsing binary payloads into structured check-in events, processing 100K+ daily scans with idempotent upserts • Refactored mobile API contracts to reduce payload size by 30%, implemented response compression and field filtering cutting latency from 1.2s to 660ms, mentored 2 junior devs on query optimization patterns