Frontend • ~14 min read

React.js vs Next.js: Complete Framework Comparison

React is the foundation; Next.js builds on it with powerful features like server-side rendering, static generation, and file-based routing. This guide covers architecture, performance, SEO, and when to choose each framework.

Overview and relationship

React is a JavaScript library for building user interfaces with components. It handles the view layer—rendering UI and managing state—but leaves routing, data fetching, and build configuration to you or other libraries.

Next.js is a React framework that adds a full-featured development environment on top of React: server-side rendering (SSR), static site generation (SSG), API routes, automatic code splitting, file-based routing, and production optimizations out of the box.

Think of it this way: React is the engine; Next.js is the complete car.

React fundamentals

React (created by Meta) revolutionized frontend development with its component-based architecture and declarative approach to building UIs.

Core concepts

Basic React component

import { useState } from 'react';

function Counter() {
  const [count, setCount] = useState(0);
  
  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>
        Increment
      </button>
    </div>
  );
}

What React doesn't include

Advantages

Disadvantages

Next.js fundamentals

Next.js (created by Vercel) is a full-stack React framework that provides structure and features for production-ready applications.

Key features

Basic Next.js page (App Router)

// app/page.tsx
export default function Home() {
  return (
    <div>
      <h1>Welcome to Next.js</h1>
      <p>Server-rendered by default</p>
    </div>
  );
}

// This page is server-rendered automatically

Advantages

Disadvantages

Rendering strategies

Rendering strategy is the biggest difference between React and Next.js.

Client-Side Rendering (CSR) - React default

Server-Side Rendering (SSR) - Next.js

Static Site Generation (SSG) - Next.js

Incremental Static Regeneration (ISR) - Next.js

Routing comparison

React (with React Router)

import { BrowserRouter, Routes, Route } from 'react-router-dom';

function App() {
  return (
    <BrowserRouter>
      <Routes>
        <Route path="/" element={<Home />} />
        <Route path="/about" element={<About />} />
        <Route path="/blog/:id" element={<BlogPost />} />
      </Routes>
    </BrowserRouter>
  );
}

Next.js (Pages Router)

pages/
  index.tsx         → /
  about.tsx         → /about
  blog/
    [id].tsx        → /blog/:id

Next.js (App Router - newest)

app/
  page.tsx          → /
  about/
    page.tsx        → /about
  blog/
    [id]/
      page.tsx      → /blog/:id

Performance and optimization

React performance considerations

Next.js performance features

Core Web Vitals

Next.js is optimized for Core Web Vitals out of the box:

SEO capabilities

React SEO challenges

Next.js SEO advantages

Example: Next.js metadata

// app/page.tsx
export const metadata = {
  title: 'My Page Title',
  description: 'Page description for SEO',
  openGraph: {
    title: 'OG Title',
    description: 'OG Description',
    images: ['/og-image.jpg'],
  },
};

export default function Page() {
  return <h1>Content</h1>;
}

Feature comparison

FeatureReactNext.js
RenderingClient-side onlySSR, SSG, ISR, CSR
RoutingExternal library neededFile-based, built-in
Code splittingManualAutomatic
SEOChallengingExcellent
API routesNoYes
TypeScriptManual setupFirst-class support
Image optimizationNoBuilt-in
DeploymentStatic hostingVercel, Node server, static

When to use each

Choose React when:

Examples:

Choose Next.js when:

Examples:

Hybrid approach

Many companies use both:

This gives you best of both worlds: public pages get SSR/SSG benefits, while the application uses flexible CSR.