Next.js Folder Zen: Padroneggiare la Directory app/

Next.js 13+ introduced the App Router with the app/ directory, replacing the old pages/ router with a file-based architecture that controls routing, layouts, and rendering behavior. Special files like page.tsx, layout.tsx, loading.tsx, and error.tsx define route behavior, while nested layouts enable complex UIs without code duplication. Route groups and dynamic routes provide scalable project organization for large applications.