React Query + Zustand Clean Architecture Patterns

State management architecture for React/Next.js applications using TanStack Query v5 and Zustand 5.

The Boundary

React Query cache  ─── server state (single source of truth)
useState           ─── local form / ephemeral component state
Zustand            ─── client-only UI state (NO server mirrors)

The anti-pattern this replaces:

API → React Query → useEffect hydration → Zustand items[] → Components
        fetch              mirror               store          read