State Management in React Applications - Choosing the Right Tool

Introduction

State management is one of the most critical aspects of building React applications. As applications grow in complexity, choosing the right state management solution becomes increasingly important. After using React Query for six months in production, I want to share my insights on when to use React Query versus Redux.

Understanding Server State vs Client State

Before diving into the comparison, it's crucial to understand the difference between server state and client state:

Server State:

• Data that originates from an external source (API, database)
• Requires asynchronous APIs for fetching and updating
• Has a source of truth you don't control
• Can become stale if not updated regularly

Client State:

• Data that is entirely managed within the application
• Synchronous and immediately available
• You are the source of truth
• Examples: UI state, user preferences, form data

React Query: The Server State Champion

React Query excels at managing server state. Here's why:

Automatic Caching

const { data, isLoading } = useQuery(['users'], fetchUsers);

React Query automatically caches your data and handles cache invalidation intelligently.

Background Refetching

React Query keeps your data fresh by refetching in the background when:

• The window regains focus
• The network reconnects
• The query is mounted

Optimistic Updates

useMutation(updateUser, {
  onMutate: async (newUser) => {
    await queryClient.cancelQueries(['users']);
    const previousUsers = queryClient.getQueryData(['users']);
    queryClient.setQueryData(['users'], (old) => [...old, newUser]);
    return { previousUsers };
  },
  onError: (err, newUser, context) => {
    queryClient.setQueryData(['users'], context.previousUsers);
  },
});

Redux: The Client State Manager

Redux is still valuable for complex client-side state:

When to Use Redux

• Complex UI state that many components need
• State that doesn't come from a server
• When you need time-travel debugging
• When you have complex state update logic

Redux Toolkit

Modern Redux with Redux Toolkit is much simpler:

const userSlice = createSlice({
  name: 'user',
  initialState: { theme: 'dark', language: 'en' },
  reducers: {
    setTheme: (state, action) => {
      state.theme = action.payload;
    },
  },
});

My Recommendation

After six months of using React Query in production, here's my recommendation:

1. Use React Query for server state - API calls, data fetching, caching
2. Use React Context or Zustand for simple client state - Theme, user preferences
3. Use Redux only when you have truly complex client state - Multi-step forms, complex UI workflows

The combination of React Query for server state and a lightweight solution for client state has simplified our codebase significantly and reduced boilerplate by over 50%.

Conclusion

The key insight is that server state and client state are fundamentally different and should be managed with different tools. React Query has become my go-to for anything that involves external data, while keeping simpler solutions for local UI state.