Lifan worked on the BerriAI/litellm repository, focusing on backend reliability for API deployments. He addressed a bug affecting Swagger UI path handling when using server_root_path by programmatically adding a servers field to the OpenAPI schema, ensuring correct routing through reverse proxies and subpath deployments. Using Python, he implemented and validated this solution with targeted tests that covered various deployment scenarios, demonstrating skills in API development and test-driven backend engineering. This work improved production reliability and simplified deployment configurations, reflecting a thoughtful approach to OpenAPI schema manipulation and robust testing practices within a short, focused development period.