Next.js Introduction

Next.js is a framework built on top of React that makes it easier to create fast and modern websites. It handles things like page rendering, routing, and performance automatically, so developers can focus on building features.

• Next.js can be used for both frontend (UI) and backend (API routes), making it a full-stack framework.
• Server-Side Rendering (SSR) Pages are generated on the server at request time, giving better SEO and performance.
• Static Site Generation (SSG) Pages can be pre-built at build time for faster loading and scalability.
• It simplifies routing, styling, and performance so beginners can build modern apps without extra setup.

"Hello, World!" Program in Next.js

// pages/index.js
export default function Home() {
    return (
        <div>
            <h1>Hello, World!</h1>
        </div>
    );
}

Output

In this example :

• The code resides in pages/index.js, defining the home page for the root route (/).
• Declares a functional component named Home that renders the UI.
• Outputs JSX, displaying "Hello, World!" inside an <h1> tag within a div.
• Exports the Home component, enabling Next.js to render it as the default page.

Before starting to learn Next.js we need to install Next.js on our system

Working of Next.js

Next.js works as a bridge between the server and the browser. It decides how pages are rendered and delivered, ensuring speed, SEO, and a smooth user experience.

Node.js

• Next.js runs on top of Node.js, which acts as the backend environment to execute JavaScript outside the browser.
• It handles server requests and responses efficiently.

Next.js Framework

• Provides Routing (file-based system for pages).
• Supports Server-Side Rendering (SSR), Static Site Generation (SSG), and Incremental Static Regeneration (ISR) to improve performance and SEO.
• Works as the bridge between backend logic and frontend rendering.

React Components

• Next.js uses React to build the UI components of the application.
• These components are rendered on the server (SSR) or pre-generated (SSG) before being sent to the browser.

Browser (Client-Side)

• The final HTML, CSS, and JavaScript are delivered to the user’s browser.
• Thanks to Next.js optimizations and CDN support, users see a fast, SEO-friendly, and interactive web app.

This is how Next.js works to deliver fast and optimized web applications.

React Vs Next.js

Both are popular choices for web development, but they serve different purposes and offer different levels of functionality.

React.js:

• A JavaScript library used mainly for building UI components on the client-side.
• Handles only the frontend, needs extra setup for routing, SEO, and backend features.

Example of building a blog page with Reactjs:

// React.js
import React, { useEffect, useState } from "react";
import { BrowserRouter as Router, Route } from "react-router-dom";

function Blog() {
  const [posts, setPosts] = useState([]);

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

  return (
    <div>
      <h1>My Blog</h1>
      {posts.map(post => <p key={post.id}>{post.title}</p>)}
    </div>
  );
}

export default Blog;

• You create a Blog.js component.
• To handle routing, you install a separate package like React Router.
• To fetch blog posts, you use useEffect() and fetch() inside the component.
• The page is rendered on the client-side, so search engines may not immediately see the content (bad for SEO)

In React.js, you need extra libraries (like React Router) and client-side fetching, which can hurt SEO.

Next.js:

• A React-based framework that supports SSR (Server-Side Rendering) and SSG (Static Site Generation).
• Provides built-in routing, SEO optimization, and full-stack capabilities out of the box.

Example:

// Next.js
export default function Blog({ posts }) {
  return (
    <div>
      <h1>My Blog</h1>
      {posts.map(post => <p key={post.id}>{post.title}</p>)}
    </div>
  );
}

export async function getServerSideProps() {
  const res = await fetch("https://example.com/api/posts");
  const posts = await res.json();
  return { props: { posts } };
}

• You create a pages/blog.js file.
• Routing is automatic (no need for React Router).
• Data fetching can be done with getServerSideProps() or getStaticProps().
• The page is pre-rendered on the server-side, so search engines see the content immediately (good for SEO).

In Next.js, you get built-in routing and server-side rendering, making your app faster and SEO-friendly with less setup.

History of Next.js

• Next.js was created by Vercel (formerly ZEIT) to simplify the development of React applications with server-side rendering.
• The framework quickly gained popularity due to its performance optimizations and ease of use.
• The current stable version of Next.js is 15.5.0, released on August 20, 2025.
• The framework continues to evolve, introducing new features with each update.

Applications of Next.js

• Web Development: Next.js is widely used to build fast, SEO-friendly websites and web applications such as blogs, e-commerce platforms, and portfolios.
• Enterprise Applications: Companies use Next.js to develop scalable, secure, and high-performance enterprise apps with server-side rendering and API integration.
• E-commerce Platforms: With built-in SSR and SSG, Next.js powers online stores to load faster, rank better on search engines, and provide smooth user experiences.
• Content-Heavy Websites: Next.js is perfect for news portals, documentation sites, and blogs where SEO and performance are crucial.
• Dashboards and Analytics Tools: Next.js can handle dynamic data rendering and integrates well with APIs, making it ideal for dashboards and data-driven apps.

Features of Next.js

Next.js comes with powerful built-in features like SSR, SSG, API routes, and file-based routing that make development faster and easier.

• Server-Side Rendering (SSR): Next.js allows developers to pre-render pages on the server at request time, providing better performance and SEO compared to traditional client-side rendering.
• Static Site Generation (SSG): Next.js offers static site generation for pages that don’t change frequently. This process involves generating HTML pages at build time, which are then served to users directly from a CDN.
• API Routes: Next.js provides a simple way to create API endpoints within your application, eliminating the need for a separate backend server.
• File-Based Routing: Next.js uses a file-based routing system where routes are created by simply adding files and folders to the pages directory. This makes it easy to organize and manage your application’s structure.
• Automatic Code Splitting: Next.js automatically splits your code into smaller chunks, ensuring that only the necessary JavaScript is loaded for each page.
• Hot Module Replacement (HMR): HMR allows developers to see changes in real-time without needing to refresh the browser, significantly speeding up the development process.
• Built-In CSS and Sass Support: Next.js includes support for importing CSS and Sass files directly into your components, making it easy to style your application without additional configuration.
• Image Optimization: Next.js 15 introduced built-in Image Optimization, which automatically serves images in the best format and size, improving performance across devices.
• Streaming Metadata (Next.js 15): Streaming Metadata allows asynchronous metadata fetching without blocking page rendering or client-side transitions, improving the performance of your application.
• Turbopack Performance Enhancements (Next.js 15): The Turbopack bundler has been optimized for faster compile times and reduced memory usage, enabling a better development experience.