React Server Components: Concepts and Patterns

React Server Components (RSC) are a significant overhaul of React's architecture, enabling optimizations such as reduced bundling size and safer requests, ultimately benefiting the end-user experience. The shift began with Concurrent React and Suspense, which created slots for asynchronous components to fill once data was available. RSC allows shipping only resources used during rendering, reducing client-side bloat. By leveraging server components, developers can tackle data fetching on the server-side, unlocking caching layers and pre-fetching/preloading of resources to maximize deliverability performance. Next.js is the only framework with React Server Components ready for production use, offering big UX and DX improvements through routing and error boundaries. RSC enables calling promises within rendering logic, reducing boilerplate code, and allows pushing user interactivity to the leaves of the rendering tree. Frameworks like Remix and Next.js have implementations of "server actions" to address pending UI states and optimistic transitions, aligning with progressive enhancement. Ultimately, RSC is a step towards a better, more performant, and high-quality web, but its suitability depends on the application's requirements.