Mastering React Server Components: Understanding the Server/Client Boundary React Server Components introduce a different way of thinking about frontend architecture. The biggest shift isn't simply that some components render on the server. The important question is: What actually needs to run in the browser? Understanding this question makes RSC much easier to reason about. Server Components vs Client Components A simplified mental model is: Server Components ↓ Server rendering / data ↓ Client Components ↓ Browser interaction Server Components are useful for UI that doesn't require client-side interactivity. Client Components are appropriate when the component needs browser-side capabilities. For example: State Event handlers Browser APIs Interactive UI Client-side effects Don't make everything a Client Component One of the easiest mistakes when starting with RSC is treating "use client" as the default. It shouldn't be. Instead, start with a Server Component and introduce a Client Component when the UI actually needs client-side capabilities. This creates a more intentional boundary. Why the boundary matters The Server/Client boundary affects several areas of an application. JavaScript sent to the browser Moving unnecessary components to the client can increase the amount of JavaScript the browser needs to process. Data fetching Server Components can fetch data closer to where server-side work happens. This can simplify certain data-fetching patterns. Component architecture Instead of thinking only in terms of reusable components, developers also need to think about where those components execute. Performance Reducing unnecessary client-side work can improve the amount of work performed by the browser. But RSC shouldn't be treated as an automatic performance solution. The application still needs good data fetching, caching, rendering and asset strategies. When should a component be client-side? A useful starting checklist is: Does it need useState? Does it need event handlers? Does it access browser APIs? Does it require client-side effects? Does it depend on a library that requires the browser? If the answer is no, there may be no reason to move that component to the client. Composition becomes important A common pattern is to keep larger parts of the UI on the server while isolating interactive pieces. For example: Dashboard │ ├── Server Component │ ├── Header │ ├── Data │ └── Statistics │ └── Client Component ├── Filters └── Interactive Controls The interactive portion can remain client-side without turning the entire page into a Client Component. RSC isn't about eliminating Client Components This is an important distinction. The goal isn't: Server Components everywhere. The goal is: Use the appropriate execution environment for each part of the application. Server Components and Client Components solve different problems. Good architecture comes from understanding that difference. The mental model I use When creating a component, I ask: What does this component need? Where does that work need to happen? Does the browser actually need this code? Can the server handle the data/rendering work? Where should the client boundary begin? That mental model is more useful than memorizing a list of RSC rules. Final takeaway React Server Components are not simply a new rendering technique. They introduce another architectural dimension: Where should this code execute? Once that question becomes part of component design, the Server/Client model becomes much easier to reason about. Full article: https://www.anujbansaldev.in/blog/mastering-react-server-components Keywords: React Server Components, RSC, Next.js, React, JavaScript, Server Rendering, Client Components, Frontend Architecture, Web Performance