React Server Components (RSC) Migration Guide

Introduction

React Server Components (RSC) represent a major shift in how modern React applications are built. Instead of running everything on the client side, React can now render parts of your app directly on the server, helping you reduce bundle size, improve performance, and simplify data-fetching logic.

If your application is currently on an older React version or using only Client Components, migrating to RSC may feel overwhelming—but don’t worry. This guide explains everything in simple and natural language, from folder structure to best practices, with examples to help you smoothly adopt the latest React architecture.

What Are React Server Components (RSC)?

React Server Components allow React to render certain components on the server instead of the browser. This helps:

Reduce JavaScript bundle size
Improve loading speed
Allow direct access to databases or server APIs
Remove the need for complex API routes in some cases

Simple Explanation:

Instead of shipping all components to the browser, you decide which ones run on the server and which ones run on the client. Components running on the server never reach the user's browser as JavaScript—they are sent as an HTML-like payload.

This results in better performance and cleaner architecture.

Why Should You Migrate to RSC?

Here are the main benefits of switching to React Server Components:

1. Faster Page Load

Only essential components run in the browser. Server-side components reduce JavaScript weight, helping pages load faster.

2. Improved SEO

Server-rendered content is easier for search engines to understand.

3. Simplified Data Fetching

You can fetch data directly inside Server Components using async functions.

4. Better Security

Sensitive logic stays on the server instead of exposing it in the client.

5. Reduced Backend + Frontend Communication

In many cases, you no longer need API endpoints for simple database queries.

How to Know if Your App Is Ready for RSC?

Your app is ready when:

You are using a modern React setup (e.g., Next.js App Router or a Vite-based setup with RSC support)
You want to reduce bundle size
You have repeated API calls handled in client components
You want better SEO and performance

If your app uses heavy client-side logic, don’t worry—RSC is flexible and works alongside traditional React components.

Recommended Folder Structure for RSC

A clean folder structure helps keep server and client components organized.

Suggested Folder Layout:

src/
  components/
    server/
      Header.jsx
      ProductList.jsx
    client/
      Button.jsx
      Dropdown.jsx
  app/
    page.jsx
    layout.jsx
    api/
  lib/
    db.js

Explanation:

server/ folder → Components rendered on the server (default in Next.js 13+)

client/ folder → Components requiring interactivity (buttons, forms, modals)

app/ folder → Routes, layouts, and RSC-based pages

lib/ folder → Database utilities and shared logic

This separation keeps the application easier to understand and maintain.

How to Create a Server Component

Server Components are the default in modern React setups.

Example:

export default async function Products() {
  const data = await getProducts();
  return (
    <div>
      <h2>Product List</h2>
      <ul>
        {data.map(item => (
          <li key={item.id}>{item.name}</li>
        ))}
      </ul>
    </div>
  );
}

Key Points:

No "use client" at the top
You can use async functions directly
This code never runs in the browser

How to Create a Client Component

Client Components require a special directive:

Example:

"use client";

import { useState } from "react";

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

  return (
    <button onClick={() => setCount(count + 1)}>
      Count: {count}
    </button>
  );
}

Use this only for components needing:

Click events
Forms
State management
Animations

Best Practices When Migrating to RSC

Here are important guidelines to follow for a smooth migration.

1. Keep Server Components as Default

Only use Client Components when needed. This keeps your JavaScript bundle smaller.

2. Move Data Fetching to Server Components

Instead of using useEffect for loading data, fetch it directly inside your Server Component.

3. Use Client Components for UI Interactions

Any component that needs useState, useEffect, or event handlers must be a Client Component.

4. Avoid Passing Server Functions to Client Components

Client Components cannot receive server-side functions as props.

5. Keep Client Components Small and Focused

Let Server Components handle logic; let Client Components handle UI interaction.

Common Pitfalls to Avoid

Migrating to RSC can lead to some mistakes if you're not careful.

1. Using Client Hooks in Server Components

Hooks like useState or useEffect will cause errors.

2. Fetching Data in Client Components

This leads to unnecessary loading states and slower pages.

3. Mixing Server and Client Logic Together

Keep a clear separation.

Server = logic, data, rendering
Client = interaction

4. Forgetting "use client" Directive

If your component needs interactivity, add the directive at the top.

5. Circular Imports Between Server and Client Components

Always maintain a clean hierarchy.

Migration Strategy — Step-by-Step

Follow this process to migrate your existing React app.

Step 1: Identify Components That Can Become Server Components

Look for components that:

Only display data
Fetch data
Don't use React hooks

Step 2: Move Data Fetching to the Server

Rewrite your data logic using async functions.

Step 3: Convert UI Components to Client Components

Add "use client" at the top when interaction is needed.

Step 4: Organize Your Folder Structure

Separate server and client logic for easier maintenance.

Step 5: Test Each Page After Migration

Check:

Rendering issues
Client hydration errors
Data fetching correctness

Step 6: Optimize Slowly

Do not convert everything at once—migrate feature by feature.

Conclusion

Migrating to React Server Components brings major improvements in performance, clarity, and user experience. By separating server-rendered UI from client-side interactions, your application becomes faster, lighter, and easier to maintain. With a clean folder structure, proper use of server and client components, and awareness of common mistakes, you can successfully adopt the latest React architecture and unlock modern capabilities.