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React Server Components: Complete Guide for Next.js 14/15

Oct 26, 2025•
reactnextjsrscperformance
•
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React Server Components (RSC) shift rendering and data fetching to the server for better performance and smaller bundles. This guide explains practical patterns in Next.js 14/15.

Executive summary

  • Fetch data in server components; stream UI with Suspense; keep client components minimal
  • Cache smartly (revalidate, tags); use actions for mutations; co-locate queries
  • Migrate gradually: shared layouts, isolate client-only islands

Data fetching patterns

// app/users/page.tsx (Server Component)
import { fetchUsers } from "@/lib/api"
export default async function Page() {
  const users = await fetchUsers()
  return (
    <ul>
      {users.map(u => <li key={u.id}>{u.name}</li>)}
    </ul>
  )
}

Streaming with Suspense

// app/page.tsx
import { Suspense } from "react"
import Feed from "./Feed"
export default function Page() {
  return (
    <Suspense fallback={<p>Loading…</p>}>
      <Feed />
    </Suspense>
  )
}

Caching and revalidation

  • Static (default) vs dynamic; revalidate seconds; route segment configs; tag‑based invalidation

Mutations with Server Actions

// app/actions.ts
'use server'
export async function createPost(data: FormData) { /* write */ }

Client interop

  • Mark components 'use client' only when needed (state, effects, event handlers)

Migration

  • Identify heavy client bundles; move fetch/compute to server components; keep UI behavior in islands

FAQ

Q: When to use client components?
A: Only for browser APIs, interactive state, or effects—keep the rest on the server.

  • Core Web Vitals: /blog/web-performance-optimization-core-web-vitals-2025
  • Micro‑Frontends: /blog/micro-frontends-architecture-module-federation-2025
  • PWAs Offline‑First: /blog/progressive-web-apps-offline-first-architecture-2025
  • React Patterns: /blog/react-design-patterns-hooks-context-state-management
  • GraphQL Federation: /blog/graphql-federation-microservices-api-gateway-2025

Call to action

Migrating to RSC on Next.js? Get a migration plan and review.
Contact: /contact • Newsletter: /newsletter

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