No QueryClient set ⚛️ React

Error: No QueryClient set, use QueryClientProvider to set one

TanStack Query hooks ran outside a QueryClientProvider (or a duplicate copy of the library is installed).

Seen on: React

Meaning

useQuery needs the client from context. Missing provider, tests without it, or two versions of @tanstack/react-query (separate contexts) cause it.

Common causes

  • QueryClientProvider missing at the root
  • Tests rendering without a provider
  • Duplicate library versions / monorepo duplicates

⚡ Quick fix

  1. Wrap the app in <QueryClientProvider client={queryClient}>
  2. Provide a wrapper in tests
  3. Deduplicate with npm ls @tanstack/react-query

Detailed fix by platform

React

  1. jsx
    const queryClient = new QueryClient();
<QueryClientProvider client={queryClient}><App /></QueryClientProvider>

How to diagnose

  1. Provider — At the root?
  2. Copies — One library version?

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