The App Router is one of the most significant changes in Next.js 13+ and has been refined in Next.js 16. Let's explore how it works and why it matters.
What is the App Router?
The App Router is a new paradigm for building Next.js applications. It introduces Server Components by default, nested layouts, and a more intuitive file system routing structure.
Key Concepts
File-based Routing
Every folder in the app directory becomes a route. The page.tsx file defines the UI for that route.
Layouts
Layouts are shared UI that wrap pages. They persist across navigation and don't re-render.
Server Components
By default, all components are Server Components. This means they render on the server and stream to the client.
Migration from Pages Router
Migrating from the Pages Router requires understanding the new patterns. Start with simple pages and gradually move complex features.
Best Practices
- Use Server Components by default
- Only use "use client" when necessary
- Leverage parallel and intercepting routes
- Implement proper error boundaries
Conclusion
The App Router represents the future of Next.js. While there's a learning curve, the benefits in performance and developer experience are worth it.