Over a two-month period, contributed to the Expensify/App and callstack-internal/Expensify-App repositories by delivering twelve new features focused on expense transaction management, policy approvals, and user experience improvements. Leveraged JavaScript, TypeScript, and React to enhance IOU flows, contact method processes, and report generation, emphasizing data validation and robust state management. Implemented optimistic UI updates for faster feedback and refactored transaction logic to improve reporting accuracy and maintainability. Strengthened code quality through targeted refactoring and expanded test coverage using Jest. The work enabled smoother workflows, reduced reconciliation errors, and supported safer deployments without introducing regressions or unresolved bugs.