Worked on the JustJirka/P6PP repository to enhance scheduling reliability by implementing booking availability validation for both rooms and trainers. Developed backend logic in C# to check for overlapping service times during creation or update, ensuring that double-bookings are prevented at the API level. Incorporated validation logic that raises exceptions when conflicts are detected, thereby enforcing data integrity and reducing the need for manual conflict resolution. Focused on database management to support these checks, the solution improves overall booking reliability and lays the foundation for future scheduling enhancements. The work demonstrates a methodical approach to backend and validation logic development.