React Server Components (RSC) render on the server, fetch data directly, and stream HTML to the browser. Unlike traditional SSR, no JavaScript for the component ships to the client — dramatically reducing bundle size for components that do not need interactivity.
Benefits: direct database and secrets access from the component tree, drastically smaller client bundles, natural streaming for slow data sources, and the ability to compose server and client components freely.
Production adoption: Next.js App Router built on RSC by default in 2023. Remix adopted a related model. TanStack Start and Waku are RSC-native. RSC is now the mainstream pattern for React applications that value performance and simplicity.