SupaVlog is a video blog starter kit built with Supabase, Stream, Hookdeck, and Next.js that enables easy creation of scalable video-based applications. The features include user sign up, login, recording vlogs in the browser, video and thumbnail storage, and viewing lists of all or specific user's vlogs. The system architecture consists of components such as authentication, database, video recording, queueing, and image storage, which are offloaded to reliable third-party services like Supabase, Stream, and Hookdeck. Next.js is used for the front-end application deployment, while Vercel ensures reliability and scalability. The components communicate through various webhook events and interactions with the database and storage services.