Tim joins Sam to talk about his work on the new app router in Next.js 13. He explains how the app router leverages Server Components and React’s new cache API to bring a new level of composability to server-side code, how Server Actions are being designed to enable partial revalidation in a single round trip to the server, and how to think about UI updates as a result of server-side state changes.Topics include:0:00 - Intro2:53 - Rendering Server Components and the RSC payload21:49 - Composition vs. top-down data flow and the React cache53:35 - Revalidation after a user event and Server Actions1:06:37 - Revalidation after a server-side state change1:14:02 - Back and forward navigation1:21:43 - Caching layers1:30:53 - Current focus on stability, performance, education, and TurboPackLinks:Tim’s deep dive on caching and revalidatingNext.js docs on Caching