In the vast landscape of React state management, two powerful libraries often stand out: Redux and React Query (now TanStack Query). Redux has been a long-standing champion for managing global application state, while React Query has revolutionized server state management. While they serve different primary purposes, the question often arises: "Can they be used together, and if so, how?" The answer is a resounding yes, and in this post, we'll explore the nuances of combining them effectively.
Understanding Their Strengths
Before diving into integration, let's quickly recap what each library excels at:
- Redux (and Redux Toolkit):
- Ideal for global client-side state that isn't derived from an API (e.g., theme settings, user preferences, modal visibility, complex wizard form data).
- Provides a single source of truth for predictable state management.
- Excellent for handling complex application-wide logic, often involving multiple reducer interactions.
- Strong ecosystem with dev tools, middleware, and extensive community support.
- React Query (TanStack Query):
- Specializes in server state management.
- Handles data fetching, caching, background re-fetching, data synchronization, and mutations.
- Out-of-the-box features like automatic retries, deduplication, stale-while-revalidate, and prefetching.
- Reduces boilerplate code significantly for data fetching compared to traditional Redux thunks/sagas.
- Improves UX by making UI feel more responsive and resilient to network issues.
Why Combine Them?
The core reason to use them together is to leverage their individual strengths without forcing one to do the job of the other. They are not mutually exclusive; rather, they are complementary.
- React Query for Server Data, Redux for UI/Client Data: This is the most common and recommended pattern. Let React Query handle all your API interactions, caching, and background synchronization. Reserve Redux for managing truly client-side, global UI state (e.g., "is a particular sidebar open?", "what's the current theme?", "user authentication status *after* it's been received and validated").
- Reduced Boilerplate for Data Fetching: By offloading data fetching to React Query, you can drastically cut down on the number of actions, reducers, and thunks/sagas needed in Redux for mere data management.
- Improved Performance and UX: React Query's intelligent caching and background updates ensure your UI is always showing fresh data and feels snappy, while Redux manages the non-API related global state without interference.
When NOT to Put React Query Data in Redux
A crucial point of confusion is often whether to store data fetched by React Query within the Redux store. Generally, you should NOT do this.
- React Query already has its own highly optimized cache for server data. Duplicating this data in Redux is redundant and creates two sources of truth, leading to potential inconsistencies and unnecessary complexity.
- You would lose all the benefits of React Query's intelligent caching, garbage collection, and automatic re-fetching if you manually manage the data lifecycle in Redux.
How to Use Them Together: Practical Scenarios
The integration isn't about deep coupling, but rather about clear separation of concerns and occasional, deliberate communication.
1. Clear Separation of Concerns (Recommended)
This is the simplest and most effective approach:
- Use React Query for all API interactions:
- Fetching user profiles, product lists, order details.
- Mutating data (e.g., submitting forms, updating records, deleting items).
- Invalidating caches after mutations.
- Use Redux for global client-side application state:
- User authentication status (e.g.,
isAuthenticated: true/false) and possibly a simpleuserId, but not the full user object (let React Query handle that). - Theme settings (dark/light mode).
- Global notification messages (toasts).
- State of global UI components (e.g., a shared modal's visibility).
- Complex multi-step form data that is not yet submitted to the server.
- User authentication status (e.g.,
Example: User Authentication
Let's say you have an authentication flow. React Query can handle the login/logout mutations and fetching the user profile:
// React Query for fetching user data
const { data: user, isLoading } = useQuery(['currentUser'], fetchCurrentUser);
// In a component
if (isLoading) return <LoadingSpinner />;
if (!user) return <LoginForm />; // User not logged in or session expired
// Redux for managing the *auth status* derived from RQ, and possibly a simple flag
// You might dispatch this after a successful login mutation or on app load
// if the user query succeeds.
// authSlice.js
// state: { isAuthenticated: boolean, status: 'idle' | 'loading' | 'succeeded' | 'failed' }
dispatch(setAuthenticated(true)); // Or based on `user` presence
Here, the actual user data (name, email, etc.) is managed by React Query. Redux only holds a derived boolean isAuthenticated and possibly the global auth status (loading, success, error) which might influence UI globally.
2. Bridging Data (When Absolutely Necessary)
There might be rare cases where a piece of data fetched by React Query needs to influence a Redux-managed state that cannot directly access React Query. For instance, if a specific user ID fetched by React Query needs to be globally available for logging or for a very specific Redux-driven analytics feature.
- Dispatching Derived Data: You can listen to React Query's `onSuccess` callback for a query/mutation and then dispatch an action to Redux with *only the necessary derived information*, not the whole data object.
// Example: Dispatching a user ID to Redux after successful login
const loginMutation = useMutation(loginUser, {
onSuccess: (data) => {
// data.userId is just one piece of info, not the whole user object
dispatch(setLoggedInUserId(data.userId));
dispatch(showToast('Login successful!')); // Redux for global toast
},
onError: (error) => {
dispatch(showToast('Login failed: ' + error.message));
}
});
In this scenario, React Query still manages the login request and response data, but a small, specific piece of information (userId) is passed to Redux for a distinct, Redux-managed purpose.
3. Using React Query's Cache Directly in Components
Often, if Redux needs to know something about server data, the component that uses Redux could simply query React Query's cache directly using useQuery or queryClient.getQueryData(). This keeps the concerns separate and avoids unnecessary Redux dispatches.
// Component using Redux for theme, but also needs user data
import { useSelector } from 'react-redux';
import { useQuery } from '@tanstack/react-query'; // Or '@tanstack/react-query'
function Header() {
const theme = useSelector(state => state.settings.theme);
const { data: user } = useQuery(['currentUser']); // Get user from RQ cache
return (
<header className={theme}>
<h1>Welcome, {user ? user.name : 'Guest'}</h1>
{/* ... other header content */}
</header>
);
}
This approach is clean and leverages React Query as the single source of truth for server data.
Conclusion
React Query and Redux are not competitors; they are specialized tools that shine in different areas. By embracing their distinct strengths, you can build more robust, maintainable, and performant React applications.
- Default Rule: Use React Query for anything related to server data (fetching, caching, mutations). Use Redux for global client-side UI state that doesn't originate from an API.
- Avoid Duplication: Do not store data fetched by React Query into your Redux store, as it defeats the purpose of React Query's optimized caching.
- Bridge Deliberately: Only pass minimal, derived information from React Query to Redux if there's a compelling, specific Redux-managed reason for it (e.g., a simple boolean flag, an ID, or a status for global notifications).
By following these guidelines, you'll find that React Query and Redux can coexist harmoniously, making your state management clearer and more efficient.
