What is Next.js? Introduction

What is Next.js?

Next.js is a React framework for building websites and web apps. React gives you building blocks (components) for the user interface; Next.js adds everything else a real website needs: pages and URLs, server rendering, APIs, image and font optimisation, and SEO features like metadata and sitemaps.

Think of React as the engine and Next.js as the complete car: steering, brakes and seats included. You can drive React alone, but you would have to build many parts yourself.

React vs Next.js

With plain React (for example Vite), the browser downloads JavaScript and then builds the page. With Next.js, the server sends ready HTML, so the page appears faster and search engines can read it immediately.

How a Next.js page reaches the browser

1. The visitor opens a URL like /courses.
2. Next.js finds the matching file app/courses/page.jsx and runs it on the server.
3. It sends back complete HTML — the visitor sees content right away.
4. A small amount of JavaScript loads and makes interactive parts (menus, forms) work. This step is called hydration.

The simplest possible Next.js page is just a function that returns JSX:

// app/page.jsx  →  this file IS the home page "/"
export default function HomePage() {
  return (
    <main>
      <h1>Welcome to EduSite</h1>
      <p>Learn coding in Hindi + English.</p>
    </main>
  )
}

Main features you will learn

• File-based routing — create a folder, get a URL. No router setup.
• Server Components — components that run on the server and can read a database directly.
• Server Actions — handle form submissions without writing a separate backend.
• Route Handlers — build JSON APIs inside the same project (useful for mobile apps).
• Rendering choices — static (SSG), on every request (SSR) or static with refresh (ISR).
• Built-in SEO — titles, descriptions, Open Graph images, sitemap.xml and robots.txt.
• Turbopack — the fast bundler used by default in Next.js 16 for dev and build.

Who uses Next.js?

Next.js is one of the most popular ways to build React websites. It is used for company websites, e-commerce stores, dashboards, blogs and documentation sites. Knowing it is a strong skill for front-end and full-stack developer jobs in India and abroad.

What you will build in this course

In the final module you build EduSite, a complete coaching-institute website with courses, a Markdown blog, a contact form and full SEO. Here is the real home page from the project:

You can download the full source code from the Project Code box on every lesson page.

What you need before starting

Summary

• Next.js is a full-stack React framework.
• It renders pages on the server, which makes sites fast and SEO-friendly.
• Routing, APIs, forms, images, fonts and SEO are built in.
• This course uses Next.js 16 with the App Router and ends with a complete website project.