nextjs-advanced-routing

Server Actions let you handle form submissions directly from the server using the 'use server' directive. Define a function in app/actions.ts marked with 'use server', pass it to your form's action prop, and the framework automatically handles the mutation and revalidation without client-side API calls.

Intercepting Routes let you intercept navigation to show modals or drawers over existing content without changing the URL path. Use the (.)segment convention to match routes at the same level, enabling seamless modal flows that preserve navigation state and work with the browser back button.

Streaming with Suspense sends page chunks to the client progressively instead of waiting for all data. Wrap slow components in Suspense boundaries with fallbacks, and Next.js streams the HTML as data loads, improving perceived performance and Time to First Byte.

Route Handlers in route.ts files let you build REST API endpoints directly in the app directory. Handle GET, POST, PUT, DELETE, and other HTTP methods, access cookies, and integrate with Server Actions for full-stack mutations without a separate API layer.

Parallel Routes use the (@slot) convention to render multiple pages simultaneously at the same URL level, enabling independent state management and navigation within each slot. This powers complex layouts like sidebars, modals, and multi-panel dashboards that update independently.

Server Actions can read and write cookies using Next.js cookie utilities, and draft mode enables preview content from your CMS. Combine them to build authenticated features and content previews that persist state securely server-side without exposing sensitive logic to the client.