Nextjs App Router

Solid reference for building with Next.js 16 and the App Router. Covers the essentials: Server Components by default, when to reach for "use client", Server Actions for form handling, the new "use cache" directive with cacheLife and cacheTag, and Route Handlers for API routes. The async params migration is handled clearly, which matters since Next.js 16 made everything Promise-based. Also includes parallel routes with the @slot convention and practical examples with Zod validation. Most useful when you're starting a new App Router project or migrating from Pages Router and need quick patterns for the file conventions and caching strategies. Skips Pages Router entirely, which is the right call at this point.