Worked on the icanbwell/fhir-server repository to enhance data integrity and API reliability by implementing optimistic locking for resource updates. Leveraged JavaScript to introduce If-Match and ETag-based PUT semantics, preventing concurrent write conflicts and reducing race conditions. Developed comprehensive precondition failure handling and improved error reporting to align with the API contract, while expanding the test suite to cover ETag scenarios and edge cases. Enhanced backend development practices by improving operation logging for better traceability and debugging. Collaborated across teams to co-author changes, ensuring robust testing and maintainability. Focused on API development, backend development, and thorough testing throughout the process.