React Server Components (RSC): The Future of React Apps

Published: 8 Januar 2023

Introduction

React Server Components (RSC) represent a paradigm shift in how React applications are built and rendered. First introduced as an experimental feature in React 18, RSC is now evolving into a core part of modern React development, especially with frameworks like Next.js 13+ fully embracing it.

In this post, we’ll break down:

• What React Server Components are.
• How they differ from traditional Client Components.
• Why they drastically improve performance and developer experience.

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1. What Are React Server Components (RSC)?

Traditionally, React components are either:

1. Client Components – Rendered in the browser, with interactivity, hooks, and state.
2. Server-Side Rendered (SSR) Components – Pre-rendered on the server but hydrated on the client.

React Server Components (RSC) introduce a new way of rendering that runs entirely on the server, without sending JavaScript to the client.

Key Features of RSC:

✅ No client-side JavaScript needed – Components don’t ship unnecessary JS to the browser.
✅ Direct access to the database – Fetch data inside components without API calls.
✅ Seamless integration with Client Components – Mix and match as needed.

Example: In a traditional React app, fetching data requires an API call from the client. With RSC, components can fetch data directly from the server, eliminating unnecessary network requests.

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2. How Do Server Components Improve Performance?

By moving logic to the server, RSC eliminates some of the most common performance bottlenecks in React applications.

⚡ Reduced JavaScript Bundle Size

One of the biggest performance problems in large React apps is bloated JS bundles. Since RSC never sends JavaScript to the client, apps become lighter and faster.

🚀 Example:

• A traditional app might load 200KB of JavaScript for rendering a product list.
• With RSC, only HTML and minimal interactivity scripts are sent, reducing the load by 50-80%.

⚡ No Need for useEffect() for Data Fetching

With RSC, you don’t need to use useEffect() for fetching data anymore. Instead, components fetch data at render time on the server and send the final HTML to the browser.

🚀 Example:
Instead of making an API call like this:

function Products() {
  const [products, setProducts] = useState([]);

  useEffect(() => {
    fetch("/api/products")
      .then(res => res.json())
      .then(data => setProducts(data));
  }, []);

  return <ProductList products={products} />;
}

With RSC, the server fetches the data before sending HTML to the browser:

async function Products() {
  const products = await db.getProducts(); // Direct database query

  return <ProductList products={products} />;
}

🚀 Benefits:

• No extra API request from the client.
• Faster page loads with server-side fetching.
• SEO-friendly because the content is already loaded.

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3. Server Components vs. Client Components: What’s the Difference?

Feature	Server Components (RSC)	Client Components
Runs on	Server	Browser
JavaScript sent to client	❌ No	✅ Yes
Can use state (useState)	❌ No	✅ Yes
Can use effects (useEffect)	❌ No	✅ Yes
Can fetch data directly	✅ Yes	❌ No
Interactive elements (buttons, inputs)	❌ No	✅ Yes

Can You Use Both?

Yes! React encourages using Server Components for non-interactive UI and Client Components for interactive elements (like forms, buttons, or modals).

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4. How to Use React Server Components in Next.js 13+

Next.js 13 introduced the App Router (app/ directory), which fully supports RSC. By default, all components inside this directory are Server Components unless explicitly marked as Client Components.

Step 1: Create a Server Component

// app/products/page.tsx (Server Component)
import db from "@/lib/db"; // Direct database query

export default async function Products() {
  const products = await db.getProducts(); // Fetch data on the server
  return (
    <ul>
      {products.map((p) => (
        <li key={p.id}>{p.name}</li>
      ))}
    </ul>
  );
}

🚀 No extra API calls from the client – the data is already loaded!

Step 2: Use a Client Component for Interactivity

"use client"; // This makes the component interactive
import { useState } from "react";

export default function AddToCart({ productId }) {
  const [count, setCount] = useState(0);

  return (
    <button onClick={() => setCount(count + 1)}>
      Add to Cart ({count})
    </button>
  );
}

🚀 You only mark the component as "use client" when needed!

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5. When Should You Use React Server Components?

✅ Best Use Cases for Server Components:

• Static content like blogs, product listings, and dashboards.
• Fetching data from databases without extra API calls.
• Reducing JavaScript bundle size for better performance.

❌ Avoid RSC for:

• Interactive elements (buttons, forms, modals).
• Components that rely on useState, useEffect, or event listeners.

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6. Final Thoughts: Are Server Components the Future?

React Server Components are one of the biggest innovations in React since Hooks. They allow developers to build faster, more efficient apps by leveraging server-side rendering without sending extra JavaScript to the client.

💡 Key Takeaways:

• Server Components reduce JavaScript bundle size by keeping logic on the server.
• Data fetching is simpler and no longer requires useEffect().
• They work alongside Client Components to create fast, interactive applications.

As Next.js and other frameworks adopt RSC, it’s time for developers to start experimenting with them. The future of React is lighter, faster, and more server-driven – and Server Components are leading the way. 🚀