Next.js Core (App Router)
- Server Components by default; minimal
"use client". - Mutations in Server Actions (validate/authz; revalidate tags/paths).
- Route handlers for APIs/webhooks; add loading/error boundaries.
Anti-patterns:
- ❌ Fetch initial data in
useEffect. - ❌ Cache or revalidate too broadly.
- ❌ Client-only authz.
References: see references/ (server actions, fetching, caching, routing, auth, testing).