Next.js is a powerful framework built on top of React that enables developers to build production-ready web applications.
In this lesson, you will learn what Next.js is, why it exists, and when you should use it instead of plain React.
What Is Next.js?
Next.js is an open-source React framework developed by Vercel.
It provides a structured way to build applications with built-in solutions for common problems that React alone does not solve out of the box.
Next.js is not a replacement for React — it extends React with additional capabilities.
Why Was Next.js Created?
React focuses on building user interfaces, but it leaves many decisions to the developer, such as:
- Routing
- SEO optimization
- Performance optimization
- Server-side rendering
- Code splitting
As applications grew larger, these concerns became harder to manage consistently.
Next.js was created to standardize best practices and reduce boilerplate.
React vs Next.js
React by itself is a library.
Next.js is a framework.
Key differences:
- React handles UI only
- Next.js handles UI + routing + rendering strategies
- React apps are typically client-side rendered
- Next.js supports multiple rendering strategies
Next.js provides opinions and structure, which helps teams scale projects.
Rendering Strategies Explained
Next.js supports different rendering approaches:
- Client-Side Rendering (CSR)
- Server-Side Rendering (SSR)
- Static Site Generation (SSG)
- Incremental Static Regeneration (ISR)
This flexibility allows developers to choose the best strategy for each page.
SEO Problem in Traditional React Apps
In traditional React apps:
- Content is rendered on the client
- Search engines may see empty HTML
- SEO requires additional setup
Next.js solves this by rendering pages on the server or at build time, making content immediately available to search engines.
File-Based Routing
Next.js introduces file-based routing.
Instead of configuring routes manually, routes are created automatically based on the folder structure.
This reduces complexity and improves readability.
Example concept:
- pages/index.js =
/ - pages/blog.js =
/blog
We will explore this in detail in the next lesson.
Performance by Default
Next.js optimizes performance automatically by:
- Code splitting
- Lazy loading
- Optimized images
- Smart caching
These optimizations require manual configuration in plain React apps.
When Should You Use Next.js?
Next.js is a great choice when:
- SEO matters
- Performance is critical
- You are building a content-heavy site
- You want a scalable architecture
- You plan to deploy to production
For small experiments or simple widgets, plain React may still be enough.
Summary
In this lesson, you learned:
- What Next.js is
- Why it was created
- How it extends React
- Key differences between React and Next.js
- Rendering strategies
- SEO and performance benefits
In the next lesson, we will create a Next.js project and explore its folder structure.