Worked on strengthening data validation within the afet-yonetim-sistemi/ays-be backend by refining the logic for user name handling. Focused on hardening the NAME_REGEX to enforce stricter validation rules, preventing issues such as consecutive or misplaced special characters in user names. Expanded unit tests across multiple controllers to ensure comprehensive coverage of new invalid name formats, thereby reducing the risk of invalid data entering production. Utilized Java for backend development and validation, emphasizing robust unit testing practices. These efforts improved data integrity and compliance with established standards, addressing a critical bug and enhancing the reliability of user input validation processes.