Engineered a secure, scalable fintech backend from scratch using NestJS and Clean Architecture to ensure long-term maintainability. I optimized complex SQL aggregations and PostgreSQL queries to significantly improve application responsiveness. On the frontend, I built modular, highly responsive interfaces using ReactJS, TypeScript, and RefineJS. Collaborated closely with cross-functional teams to align technical feasibility with financial business goals, resulting in a high-performing, user-centric application.