What is the recommended way to handle state management in React 19?

In React 19, the state management landscape has simplified considerably. Here is what I recommend for a medium-sized e-commerce app:

Server State: Use TanStack Query (React Query) for all server-side data fetching and caching. It handles loading states, error handling, and cache invalidation beautifully. This covers products, user data, and orders.

Client State: For simple UI state, use useState and useReducer. For shared state like shopping cart and auth, Zustand is the sweet spot - simpler than Redux with excellent TypeScript support and minimal boilerplate.

URL State: Use the router (Next.js or React Router) for filters and pagination. This makes the state shareable via URLs.

You likely do not need Redux anymore for this size of application.

I still think Redux Toolkit has its place, especially for complex applications with lots of interconnected state:

The Redux DevTools are unmatched for debugging. Time-travel debugging and action logging save hours when tracking down state bugs. RTK Query is also excellent for API integration.

That said, for your 50-component e-commerce app, I agree that Zustand plus TanStack Query is probably the right call. Redux shines more in apps with 200+ components and complex state interactions.

Whatever you choose, avoid putting everything in global state. Most state should be local to components or handled by your data fetching library.

With React 19 now stable and widely adopted, I am confused about the current best practices for state management. Previously we used Redux Toolkit, but React Server Components and the new use() hook seem to change the landscape significantly.

Our application is a medium-sized e-commerce platform with about 50 components. We need to manage user authentication state, shopping cart, product filters, and UI state.

Should we still use Redux, switch to Zustand, or rely more heavily on React built-in features like Context and the new hooks? What combination works best in practice?