With Netlify Edge Functions, developers can serve content from the CDN server closest to the user, modifying network requests at the edge with JavaScript or TypeScript. PolyScale is a Global Database Cache as a Service that allows developers to cache database data locally to users, reducing latency and scaling throughput. In this tutorial, the author uses Astro as a framework and creates an Edge function using Deno to query a Supabase database through PolyScale, demonstrating how to bring edge functions to any project and make interactions with databases blazingly fast. The author sets up a Supabase database, creates a PolyScale cache, and writes an Edge function that queries the DB, showcasing the benefits of caching database data locally to users. With this setup, developers can now apply this technique to applications where they have a database setup, pulling in the edge function into the action to improve performance.