Led end-to-end development of a production-grade SaaS platform for a trading journal. Built scalable web applications with React, TypeScript, and RESTful APIs, delivering 100+ trade P&L calculations, risk-reward analytics, and win-rate insights. Implemented automated analytics dashboards and a real-time market data tracking system processing millions of data points with 99.9% uptime. Guided product decisions, defined architecture, and collaborated with stakeholders to ship a customer-focused solution.