Worked on the LifeSG/web-frontend-engine repository to deliver a file upload extension validation feature, enforcing .jpg-only uploads in line with updated policy requirements. Used React and TypeScript to implement robust front end validation, providing enhanced user feedback for unsupported file types and reducing invalid submissions. Added comprehensive tests to verify validation logic and error messaging, ensuring clarity for both users and QA teams. Also addressed and corrected confusing or inaccurate error messages within the file upload component’s tests and stories. This work improved the reliability of the upload process and strengthened the overall quality of the front end experience.