During October 2025, Xuelang Ping developed a robust MIME type detection fallback for file processing in the BerriAI/litellm repository. Addressing the challenge of missing or generic Content-Type headers, Xuelang implemented logic that leverages S3 response data to accurately infer file types, particularly for images and documents. This backend enhancement, written in Python and supported by unit testing, improved the resilience and reliability of the file ingestion pipeline. By reducing misclassification risks and lowering failure rates, Xuelang’s work ensured more accurate downstream processing and better data integrity, demonstrating depth in API integration and backend development within a production environment.