nextjs-expert

Next.js App Router data fetching supports streaming to prevent UI blocking. You can fetch data directly inside Server Components and leverage Suspense boundaries to stream content incrementally, avoiding client bundle waterfalls.

Server Actions in Next.js 14 handle form submissions by defining asynchronous functions directly within Server Components. This approach processes form data securely on the server without creating separate API routes or client-side JavaScript handlers.

Next.js middleware is ideal for authentication when you need to intercept requests before they complete. It runs on the Edge, checking user sessions and redirecting unauthorized access, whereas API routes handle backend logic and data mutation.

Next.js App Router caching automatically stores fetch responses by default to optimize data fetching. You can configure cache durations using time-based revalidation or bypass caching entirely with no-store directives for dynamic real-time data.

Large JavaScript bundles often occur when adopting client components unnecessarily. To optimize client bundles, keep components as Server Components by default and only add the use client directive when you need interactivity or browser APIs.

Parallel and intercepting routes work together in Next.js App Router to build complex interfaces. Parallel routes render multiple pages simultaneously in named slots, while intercepting routes load content modally by catching navigation within the same layout.