Managing an 80,000-line codebase with a rapidly growing user base (2,000+ MAU) and real financial stakes. The system required high concurrency for the gaming elements and banking-grade security for the trading platform. My Solution: I led a team of developers in building a robust, full-stack architecture using Python and React-TypeScript. • Process Engineering: I professionalized the development workflow, moving the team from ad-hoc coding to a structured Scrum methodology. This improved code quality and reduced regression bugs. • Security & QA: Given the financial nature of the product, I established strict testing pipelines. We treated every update as a critical financial transaction, ensuring user funds remained secure despite frequent feature deployments. • Team Leadership: I mentored junior developers and reorganized development schedules to prevent team fatigue, ensuring consistent output without sacrificing code quality.