React Server Components: Kompletní průvodce pro rok 2026

React Server Components: A Complete Guide for 2026

React Server Components (RSC) have fundamentally changed how we build React applications. Since their stable release with React 19 and deep integration with Next.js, they have become the default way to think about component architecture.

What Are Server Components?

Server Components are React components that execute exclusively on the server. They never ship JavaScript to the client, which means they can directly access databases, file systems, and other server-only resources without building API endpoints.

Key Benefits

Zero bundle size impact — Server Components don't add to your JavaScript bundle. You can import heavy libraries like syntax highlighters, markdown parsers, or date formatting libraries without worrying about client-side performance.

Direct data access — Instead of building REST or GraphQL APIs, Server Components can query your database directly using ORMs like Prisma or Drizzle.

Automatic code splitting — The boundary between Server and Client Components creates natural code-splitting points.

Server vs Client Components

The mental model is simple:

• Server Components (default): For data fetching, heavy computation, server-only resources
• Client Components ('use client'): For interactivity, browser APIs, state, effects

// Server Component (default)
async function BlogPost({ id }: { id: string }) {
  const post = await db.query.posts.findFirst({
    where: eq(posts.id, id)
  });
  return <article>{post.content}</article>;
}

// Client Component
'use client';
function LikeButton({ postId }: { postId: string }) {
  const [liked, setLiked] = useState(false);
  return <button onClick={() => setLiked(!liked)}>Like</button>;
}

Composition Patterns

The most powerful pattern is composing Server and Client Components together. Server Components can pass serializable props to Client Components, and Client Components can render Server Components via the children prop.

Performance Impact

In production applications, we've seen:

• 40-60% reduction in JavaScript bundle size
• 2-3x improvement in Time to Interactive (TTI)
• Significantly better Core Web Vitals scores

When to Use What

React Server Components are not just a performance optimization — they represent a new mental model for building web applications that is simpler, faster, and more scalable.

Originally published on IceCat Studio Blog. Based on React documentation and community best practices.