Worked on enhancing file validation workflows in the nestjs/nest repository by implementing bufferless file validation within the FileTypeValidator module. Leveraging TypeScript and Node.js, introduced an optional mimetype fallback mechanism that allows validation of files saved directly to disk, addressing scenarios where a buffer is unavailable. This approach preserved existing validation behavior when the fallback was not enabled, ensuring backward compatibility. The update improved the reliability and flexibility of backend file handling pipelines, reducing friction in production environments. The work demonstrated a focused application of backend development skills to solve practical challenges in file validation for disk-based workflows.