Routing

App Router maps folders in app/ to URL segments and builds a layout tree.

Route segments

• app/dashboard → /dashboard
• app/blog/[slug] → /blog/:slug
• Each segment can include page.js, layout.js, loading.js, error.js, not-found.js.

Nested layouts

• app/layout.js → app/dashboard/layout.js → app/dashboard/settings/layout.js.
• Layouts persist across transitions and preserve state.
• Good for shared UI: headers, sidebars, breadcrumbs.

Dynamic and catch-all routes

• [id] or [slug] for dynamic params.
• [...slug] for any depth.
• [[...slug]] also matches the root.

Special routing features

• Parallel segments (@modal, @feed) render in parallel.
• Intercepting routes ((.), (..), (...)) enable modal routes.
• Route Handlers (route.js) provide API endpoints.