Scale Optimization: Engineered and optimized core e-commerce cart functionalities for [contact hidden], successfully scaling backend services to sustain traffic peaks exceeding 35M+ monthly active users. MFE Shadow DOM Styles Fix: Resolved critical design system breakdowns across Micro Frontends (MFE) by orchestrating a dynamic injection system that registers global style payloads directly to the host document.head. This bypasses strict encapsulation boundaries and maintains cross-cart visual uniformity. State & Lifecycle Sync: Eliminated cart loading race conditions and UI freezing states by capturing deep browser-level rendering events and explicitly mapping them directly into MFE component initialization lifecycle hooks. CI/CD Pipeline Automation: Architected a dynamic test-data seeding framework within xUnit test configurations to address recurring CI/CD failures caused by mock-to-production data drifts. This fix saved approximately 15 engineering hours per week of downtime for a 6-developer team.