Worked on backend development for the langgenius/dify repository, focusing on improving API validation for document uploads. Addressed a critical issue by enforcing the presence of the data_source_type field within the data_source dictionary for both DocumentAddByFileApi and DocumentUpdateByFileApi endpoints. This Python-based solution ensures that uploads cannot proceed without required metadata, thereby preventing incomplete data submissions and reducing downstream errors in data ingestion pipelines. Leveraged skills in API development and backend systems to deliver a targeted bug fix rather than new features, demonstrating attention to data integrity and robust validation practices within the existing Python codebase over the project period.