TanStack Query as state manager

TanStack Query manages server state — caching, invalidation, mutations, refetch on focus. Many React teams now use it as their primary state tool, with minimal Redux/Zustand.

What TanStack Query covers:

• Server data — list, detail, mutations.
• Global state derived from server (current user, current org).
• Cross-page caching.
• Optimistic updates.
• Background refetch.

What you still need:

• UI state (open menus, input values) — useState or Zustand.
• Complex client-only computations — Zustand with computed values.
• Global event bus — separate pub-sub.

Setup that works:

• QueryClientProvider at root.
• Query keys as arrays with explicit hierarchy: ['users', userId, 'posts'].
• Custom hooks per data domain: useUsers(), useUser(id), usePosts(userId).
• staleTime configured per query type — frequently changing data 30s, rarely changing 5min.

In our last 8 React projects, none needed Redux. TanStack Query + Zustand for UI state covered everything cleanly.