Worked on the infiniflow/ragflow repository to implement public API file upload and runtime attachment features for chat, enabling users to upload files that can be referenced in chat completions and future conversations. Leveraged Python for backend development, focusing on robust API design and efficient file handling to ensure seamless integration of uploaded files into the chat context. Addressed a bug that previously prevented uploaded files from influencing chat conversations, thereby improving the overall chat experience. This work aligned the SDK and API to support file uploads in end-to-end workflows, demonstrating a methodical approach to backend and API development.