Redux Toolkit

Redux Toolkit is the official way to use Redux without the boilerplate that made old Redux painful. It wraps Redux with sensible defaults: built-in immutable updates, auto-generated action creators, and a data fetching layer called RTK Query.

MIT license, TypeScript-first. This is NOT a separate library from Redux: it IS how you're supposed to use Redux now. The old pattern of writing action types, action creators, and reducers separately is dead. Redux Toolkit gives you `createSlice` which generates all three from one function.

Fully free. No paid tier, no hosted version. It's a dependency in your package.json. Every team size: free. The real question isn't cost; it's whether you need Redux at all. For simple apps, React's built-in useState and useContext are enough. Redux Toolkit earns its place when you have complex state interactions across many components, or when you need RTK Query's caching and invalidation.

The catch: Redux still adds conceptual overhead. Actions, reducers, selectors, middleware, the mental model is heavy compared to simpler alternatives like Zustand or Jotai. RTK Query is powerful but competes with React Query/TanStack Query, which many developers find more intuitive. If you're starting fresh and don't already know Redux, try Zustand first.