With the introduction of React Server Components in Next.js 13+, developers can now choose where components are rendered—on the server or the client. This choice can drastically improve performance, reduce bundle sizes, and optimize user experience.

Server Components

Server Components are rendered entirely on the server. They do not ship JavaScript to the client, which means smaller client bundles and faster load times. You can use them for:

• Fetching data from APIs or databases without exposing secrets.

• Rendering static content or large lists.

• Components that don’t require user interaction.

Server Components integrate seamlessly with the App Router. You can import them directly into client components when needed, and they work alongside client-side state.

Client Components

Client Components are necessary when your component needs interactivity—state, effects, event handlers, or browser APIs. Common use cases include:

• Forms and input fields.

• Buttons with click handlers.

• Interactive charts or dynamic UI elements.

Client Components are bundled and sent to the browser, so using them only where necessary keeps your app performant.

Best Practices

1. Default to server: Start with server components whenever possible. Only switch to client components when interactivity is required.

2. Mix carefully: You can embed server components inside client components, but not the other way around. Plan your component tree with this in mind.

3. Optimize data fetching: Take advantage of server-side fetching in server components to minimize client requests.

// Server component
export default async function Posts() {
  const posts = await fetch('https://api.example.com/posts').then(res => res.json());
  return (
    <div>
      {posts.map(post => (
        <div key={post.id}>{post.title}</div>
      ))}
    </div>
  );
}

// Client component
'use client';
import { useState } from 'react';

export default function Counter() {
  const [count, setCount] = useState(0);
  return <button onClick={() => setCount(count + 1)}>Clicked {count} times</button>;
}

By combining server and client components thoughtfully, you can build apps that are fast, scalable, and maintainable.

Common Pitfalls with Client and Server Components

1. Overusing Client Components Sending too many components to the client increases bundle size and slows down rendering. Always ask: “Does this component really need interactivity?”

2. Incorrect Nesting Server components cannot include client components directly unless the client component is wrapped properly. Mistakes here can cause runtime errors.

3. Excessive Data Fetching on the Client Fetching data in client components for content that doesn’t need to be interactive defeats the purpose of server components. Prefer server-side fetching whenever possible.

Performance Tips

• Leverage Streaming: Next.js supports streaming server components. This allows your app to send parts of the UI as soon as they’re ready, improving perceived load time.

• Split Components: Break large components into smaller server components. This reduces the amount of client-side JavaScript and keeps interactivity scoped.

Cache Strategically: Use caching at the server component level for repeated data requests to avoid redundant fetching.