In Next.js

App router
- A newer router that allows you to use react’s latest features like Server components and Streaming
- Preferred in the official docs, new and more recommended
- Uses React Server Components by default
Page router
- Original Next.js router

Feature	App Router	Page Router
File-based routing	Uses nested folders to define routes	Files directly represent routes
Components	Server Components by default	Client Components by default
Data fetching	`fetch` function for data fetching	`getServerSideProps`, `getStaticProps`, `getInitialProps`
Layouts	Layouts can be nested and dynamic	Layouts are static
Dynamic routes	Supported, but syntax differs	Supported
Client-side navigation	Supported with router.push	Supported with Link component
Priority	Takes precedence over Page Router	Fallback if no matching route in App Router

Non-Next.js

React router
- The standard, most popular routing library for client-side React applications
- It’s used in React apps built with tools like Create React App or Vite (i.e., not Next.js)
- Handles routing entirely in the user’s browser (client-side). When you click a link, React Router intercepts it, prevents the browser from reloading, and just swaps out the React components to make it look like you changed pages
- It’s all about CSR!
  - server sends one minimal HTML file and a big JavaScript bundle. The user’s browser then runs the JavaScript to render the page and handle all navigation