Introduction to Next.js
Learn what Next.js is, why it exists on top of React, and how it has become the default framework for building production web applications.
What is Next.js?
Next.js is a React framework created by Vercel that adds the infrastructure a real production application needs on top of React: file-based routing, server-side rendering, static site generation, API endpoints, image and font optimization, and a build system tuned for performance — all built in, with no manual configuration required.
React by itself is a UI library — it only tells you how to render components. It doesn't know how to route between pages, fetch data on the server, or bundle your app for production. Next.js is the layer that turns React into a complete framework for building whole applications, not just individual components.
Next.js was created in 2016 by Guillermo Rauch and the team at Vercel (then called Zeit). It was one of the first frameworks to make server-side rendering with React practical for everyday developers, and it now ships new React features — like Server Components — before most other tools support them.
Why Next.js Exists
Before frameworks like Next.js, teams building a "React app" had to hand-assemble a router, a bundler (Webpack), a server-rendering setup, code-splitting, and an image pipeline — and keep them all working together as React itself evolved. Next.js exists to remove that assembly work entirely, so you can focus on building features instead of build tooling.
Problems Next.js solves out of the box:
- Routing — no need to hand-configure React Router; folders and files become routes automatically.
- Rendering — pages can be rendered on the server, at build time, or on the client, per-route.
- Data fetching — components can fetch data directly on the server before anything reaches the browser.
- Performance — automatic code splitting, image optimization, and font loading with no extra setup.
- Full-stack — API endpoints (Route Handlers) live in the same project as your UI.
Real-World Analogy
If React is a set of high-quality car parts — an engine, a chassis, wheels — Next.js is the fully assembled car with a working ignition, wiring, and dashboard. You could build the car yourself from the parts, but Next.js hands you something that already drives, so you can spend your time on where you're going instead of how the engine connects to the wheels.
React — The Engine
Provides the component model and rendering logic.
Next.js Router — The Steering
Turns your folder structure into working navigation.
Next.js Server — The Chassis
Runs your data fetching and rendering before the page reaches the browser.
What Next.js Adds on Top of React
| Capability | Plain React (Vite/CRA) | Next.js |
|---|---|---|
| Routing | Manual setup with React Router | Automatic, file-based (app/ folder) |
| Rendering | Client-side only, by default | Server, static, or client — chosen per route |
| Data fetching | Runs in the browser via useEffect/hooks | Can run on the server before the page loads |
| API endpoints | Requires a separate backend project | Built in via Route Handlers |
| Image optimization | Manual, third-party tools | Built in via next/image |
| SEO | Harder — content renders after JS loads | Strong — HTML can be fully rendered up front |
Where Next.js Is Used
E-commerce
Stores like those built on Shopify's Hydrogen use Next.js-style rendering for fast, SEO-friendly product pages.
Content & Marketing Sites
Blogs and marketing pages use static generation for near-instant page loads.
SaaS Dashboards
Server Components and streaming make data-heavy dashboards feel fast.
Streaming & Media
TikTok, Twitch, and Hulu all use Next.js for parts of their web experience.
Fintech Products
Companies like Notion and many banks use Next.js for secure, fast dashboards.
Full-Stack Products
Route Handlers let teams ship the UI and the API from a single codebase.
Common Beginner Mistakes
Next.js is built on top of React — you still write components, props, and state exactly as you would in React.
A lot of Next.js code (especially in the App Router) runs on the server, not the client — this changes how you think about data fetching.
FAQs
Yes — Next.js assumes you already understand components, props, state, and hooks. This course focuses on what Next.js adds on top of that foundation.
No — its zero-config defaults make it a great choice for personal projects and small apps too, and it scales up smoothly as a project grows.
Yes, Next.js itself is free and open-source. Vercel (its creator) also offers paid hosting, but you can deploy Next.js apps on many other platforms.
Key Takeaways
- Next.js is a React framework, not a replacement for React.
- It adds routing, rendering strategies, data fetching, and API endpoints on top of React.
- It is used across e-commerce, content sites, dashboards, and full-stack products.
Summary
Next.js takes the React you already know and wraps it in the infrastructure a real application needs — routing, rendering, and a server — so you can ship production apps without hand-building that infrastructure yourself. Next, you'll see how Next.js evolved into the framework it is today.