Server result
The browser does not receive Server Component source or its server-only dependencies.
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Server Components field guide
Classify capabilities, cut the module graph, minimize the wire.
Capability matrix
| Capability | Server Component | Client Component |
|---|---|---|
| Direct database/filesystem access | Yes, when the server environment provides it | No; use a server API or Server Function |
| Async component with awaited data | Yes | Receive data, promises, or fetch through client mechanisms |
| State and event handlers | No | Yes |
| Effects and browser APIs | No | Yes |
| Source shipped in client bundle | No | Yes, with transitive client dependencies |
| Can contribute to initial HTML | Yes | Yes, in frameworks that prerender/SSR them |
| Props crossing server → client | Produces supported serialized values/elements | Receives them over the RSC boundary |
| Context consumption | Cannot consume client context | Yes; place provider as deep as practical |
Boundary placement algorithm
- Mark components requiring state, effects, handlers, context, or browser APIs.
- Create client entry points at the smallest cohesive interactive roots.
- Trace every transitive import below each entry point; that is the actual client graph.
- Keep database clients, secrets, heavy transforms, and server-only libraries above the cut.
- Pass narrow supported serialized values—not service objects, closures, or whole records by habit.
- For visual nesting, compose Server Components in a server parent and pass them into client slots.
- Parallelize independent server reads and add Suspense where latency and fallback independence justify it.
- Measure client modules, RSC payload, server latency, hydration, caching, and navigation—not bundle size alone.
Know what crosses
Client holes
The payload identifies where Client Components belong and which client modules implement them.
Boundary props
Supported serialized props become observable client data. Treat the boundary like an API.
Correct the premise
“RSC versus SSR?”
Execution/payload partition versus initial HTML generation. They compose.
“Server means per request?”
No. Server Components can run during a build or on a live server.
“Client means browser-only HTML?”
No. Client code ships and hydrates, but may also participate in initial server HTML.
“'use server' component?”
No. It marks a callable async Server Function; Server Components have no directive.