How do you migrate from Redux to a modern state management solution?

Migrating large Redux codebases requires a strangler fig approach — incrementally replace Redux while both coexist. Step 1: Identify state categories: audit what's in Redux. Most Redux state is either: server data (should be React Query/RTK Query), or client UI state (should be Zustand/local state). Step 2: Migrate server state first: replace thunks/sagas that fetch API data with RTK Query or React Query. These are the most impactful — they eliminate loading/error boilerplate in reducers. Step 3: Migrate local state: Redux state used by only 1-2 components → local useState. State passed as props from Redux → lift to component. Step 4: Replace remaining global state: the remaining global client state (auth, theme, cart) → Zustand store or Redux Toolkit slice. Coexistence: Redux and React Query can coexist. RTK Query and React Query can both run. Migrate slice by slice, not all at once. Benefits post-migration: ~60-70% less boilerplate, faster builds (smaller bundle), better performance (targeted subscriptions), simpler testing. The migration ROI is highest when moving Redux API data to React Query.