Understanding React Server Components in Depth

What Are Server Components?

React Server Components (RSC) are components that render exclusively on the server. Unlike traditional React components, they don't have client-side interactivity — they're rendered to HTML on the server and streamed to the client.

Key Benefits

• Zero JavaScript bundle size — server components don't ship JS to the client
• Direct database access — no need for separate API routes
• Better performance — reduced client-side hydration
• Automatic code splitting

Server vs Client Components

In the Next.js App Router, all components are server components by default. To opt into client-side rendering, add the 'use client' directive at the top of your file.

// Server Component (default)
async function ServerComponent() {
  const data = await db.query('SELECT * FROM posts')
  return <div>{data.map(p => <Post key={p.id} {...p} />)}</div>
}

// Client Component
'use client'
function ClientComponent() {
  const [count, setCount] = useState(0)
  return <button onClick={() => setCount(c => c + 1)}>{count}</button>
}

When to Use Each

Use Server Components for data fetching, static rendering, and anything that doesn't require interactivity. Use Client Components for event handlers, browser APIs, state, and effects.

Conclusion

Server Components are a powerful addition to the React ecosystem. Understanding when and how to use them is key to building performant Next.js applications.