Explore the process of building a simple progressor upload service using vanilla JavaScript in this 38-minute tutorial video. Learn how to create a backend service with minimal libraries, focusing on core JavaScript functionality. Discover techniques for reading files with FileReader, slicing files into chunks, sending chunks to the backend using fetch, and implementing progress tracking on the frontend. Gain insights into potential improvements and scalability considerations for your upload service. Access the source code and additional resources to enhance your understanding of HTTP libraries, the Fetch API, and FileReader.