nextjs

Next.js Server Actions handle data mutations directly from the client. You define them within Server Components or separate files to process form submissions securely without creating dedicated API endpoints.

Use 'use client' in Next.js when you need interactivity, state, or browser APIs. The App Router defaults to Server Components for data fetching and rendering, adopting client components only where user interaction is required.

Streaming SSR in Next.js sends HTML chunks to the browser as they render. Wrapping components in Suspense allows the page to stream progressively, displaying fallback UI while waiting for slow data fetches to resolve.

Adopt domain-driven or feature-based structures for Next.js file maintainability. Grouping routing, Server Components, and data fetching logic by feature rather than file type ensures scalable application architecture.

Next.js App Router supports parallel and intercepting routes for complex layouts. Parallel routes render multiple components simultaneously, while intercepting routes handle modals and nested navigation without unmounting active contexts.

Next.js caching strategies optimize performance by storing fetched data at various levels. Understanding request memoization and full route caching ensures efficient data fetching and prevents stale content in server-rendered applications.