React Server Components: The Future of Rendering in Modern Web Apps

July 3, 2025
|
3
minute read
Blog
Written By
Cauvery Raja
As React evolves, so do the tools and techniques available to developers for building high performance, scalable web applications. One of the most exciting innovations in recent years is React Server Components (RSC)—a game-changing update that allows components to be rendered on the server, delivering performance gains and architectural flexibility.

From MPAs to SPAs: A Quick Recap

Before we dive into Server Components, let’s take a moment to understand where they fit in the broader evolution of web development.

➤ Multi-Page Applications (MPAs)

In traditional web apps, each user interaction (like clicking a link) triggered a full page reload. This MPA model was simple but slow and jarring—especially as web applications became more dynamic.

➤ Single Page Applications (SPAs)

Then came SPAs, powered by frameworks like React, Angular, and Vue. These apps load a single HTML shell and dynamically update the DOM with JavaScript. The result? Smooth, app-like experiences in the browser.

However, SPAs introduced new challenges—especially in SEO, performance, and initial page load times. As apps grew, so did their JavaScript bundles, causing longer time-to-interactive and reduced performance on low-end devices or poor networks.

Rendering Strategies in SPAs

Developers adopted different rendering techniques to balance performance, user experience, and SEO. The three most common strategies are:

  • Client-Side Rendering (CSR): The entire app is bundled and sent to the browser, which waits for JavaScript to load before rendering anything. This can result in long load times as applications grow.
  • Server-Side Rendering (SSR): HTML is rendered on the server and sent to the client, improving initial load performance and SEO. The page is later “hydrated” with JavaScript to enable interactivity.
  • Static Site Generation (SSG): HTML is pre-rendered at build time and served from a CDN. Great for content-heavy pages with low interactivity needs.

Despite these rendering strategies, developers often find themselves making trade-offs between performance, SEO, and developer experience. While SSR and SSG address some issues, they still rely heavily on client-side JavaScript to hydrate and run the app. As applications continue to scale, the need for a more efficient, flexible solution has become clear. This is where React Server Components enter the picture.

What Are React Server Components?

React Server Components bring a hybrid, component-level rendering model. You decide which components should run on the server, without sending any JavaScript to the client, and which should remain interactive and run on the client.

This enables you to:

  • Fetch data inside components, without the useEffect or client-side state
  • Avoid hydration entirely for non-interactive content
  • Dramatically reduce client bundle size

➤ Why They Matter

Here are some standout benefits:

  • Improved Performance: By offloading rendering to the server, you reduce the JavaScript payload, improving time-to-interactive.
  • Streaming Support: Pages can be streamed in chunks, allowing content to appear sooner and speeding up the perceived load time.
  • No JS for Static Parts: Components that don’t require interactivity don’t ship any JavaScript to the browser. 
  • Seamless with Client Components: Use server components for heavy lifting, and client components for interactivity—all in the same app.
  • Simplified Data Fetching: Fetch data directly inside server components—no need for useEffect or client-side state setup.

➤ How Do They Work

  1. You send a request to the server (e.g., visiting a page).
  2. React runs the Server Components to build part of the component tree on the server.
  3. While rendering:
    1. Server Components can fetch data, call databases, etc.
    2. React builds a data payload describing the rendered UI.
  4. React streams that payload to the browser.
  5. In the browser:
    1. The client React runtime takes the streamed payload.
    2. It hydrates any Client Components (i.e., attaches interactivity).
  6. The Server Components are just static HTML (not interactive).

What Is Actually Streamed Here?

React doesn't stream HTML. It streams a custom serialization format (called Flight). 

Let's take a real-world example with Server and Client component setup.

 // components/UserInfo.server.tsx
 // Server Component – rendered only on the server
 export default async function UserInfo({ userId }) {
   const user = await getUserFromDatabase(userId);
   return <div>{user.name}</div>;
 }

 // components/EditUserForm.client.tsx
 // Client Component – interactive
 'use client';


 import { useState } from 'react';


 export default function EditUserForm({ userId }) {
 const [name, setName] = useState('');


 const handleSubmit = () => {
   // send updated name to server
 };


 return (
   <form onSubmit={handleSubmit}>
     <input value={name} onChange={(e) => setName(e.target.value)} />
     <button type="submit">Save</button>
   </form>
  );
 }

// app/page.tsx (React Server Component Tree Root)
import UserInfo from '@/components/UserInfo.server';
import EditUserForm from '@/components/EditUserForm.client';


export default function Page({ params }) {
 return (
   <>
     <UserInfo userId={params.id} />   {/* rendered and streamed as HTML */}
     <EditUserForm userId={params.id} /> {/* reference sent for hydration */}
   </>
 );
}

In this case, conceptually React sends the following payload via Flight.

[
["<div>John Doe</div>"],
["EditUserForm", { userId: "123" }]
]

It might send plain HTML output for parts of the UI like <div>John Doe</div>, which can be inserted directly into the DOM without needing JavaScript. For interactive parts — like a form that requires state or event handling — the server includes a reference to a Client Component (e.g., EditUserForm) along with its props (e.g., { userId: "123" }). The client then takes this serialized data, inserts the static content into the page, and hydrates only the Client Components, loading the necessary JavaScript to make them interactive. This approach results in faster load times and smaller JavaScript bundles, as only the interactive parts of the app need to be shipped and executed in the browser.

While React Server Components sound very similar to traditional server-side rendering, they follow a fundamentally different model. Let’s take a closer look at how RSC compares to SSR—and why that difference matters.

Does it feel more like Traditional SSR?

Although both approaches render content on the server , they solve different problems and operate in fundamentally different ways, here’s a quick comparison:

Now that we understand how React Server Components differ from traditional SSR and why they matter, let’s look at how you can start using them.

How to Use React Server Components Today

The easiest way to get started is with Next.js 13+ and the App Router, which provides built-in support for RSC, enabling you to mix Server and Client Components seamlessly within your app. This setup not only simplifies routing and layouts but also gives you fine-grained control over what runs on the server and what ships to the client. 

If we take the same example we saw earlier, this would be its folder structure.

app/
├── page.tsx
components/
├── UserInfo.server.tsx       // Server Component (static)
└── EditUserForm.client.tsx   // Client Component (interactive)

Key Concepts:

  • app/ directory: Enables RSC with layouts, routing, and nested components
  • Server Components (default): Run on the server, no client JS. Rendered on the server and sent as HTML. No hydration needed, no JS sent.
  • Client Components: Use 'use client' directive at the top of the file. Interactive elements (like forms or modals) are still sent with JavaScript and hydrated on the client.

➤ When Should You Use RSC?

Use Server Components for:

  • Data-heavy UI (product lists, blog posts, dashboards)
  • Static or semi-dynamic content
  • Layouts, headers, footers, etc.

Use Client Components for:

  • Forms, modals, sliders
  • Anything that uses state or browser APIs
  • Interactive user experiences

Conclusion

React Server Components are a powerful leap forward in web architecture. They offer a way to:

  • Build faster apps with smaller bundles
  • Stream content progressively
  • Simplify data fetching and reduce complexity
  • Enhance performance without losing flexibility

They’re not a silver bullet—but when used correctly, RSC can dramatically improve both developer experience and user experience.

As React continues to unify the strengths of SSR, SSG, and CSR, Server Components will likely become a key pillar in future production apps.

Author

UI Developer
Cauvery Raja