Redux: what it is, why it matters, and when to use it

State management is one of the most important aspects of building interactive web applications. As apps grow in complexity, managing state across multiple components becomes harder. That’s where Redux comes in.

In this article, we’ll explore what Redux is, why it was created, how it works, and whether you still need it in today’s React ecosystem.

🧩 What is redux?

Redux is a state management library for JavaScript applications, most commonly used with React. It provides a predictable way to manage global state by organizing it in a single source of truth—a central store.

It was inspired by Flux (by Facebook) and built by Dan Abramov and Andrew Clark.

⚙️ How redux works (in simple terms)

At the core of Redux are a few simple concepts:

1. Store: Holds the entire application state.
2. Actions: Plain JavaScript objects that describe what happened.
3. Reducers: Pure functions that take the current state and an action, and return a new state.
4. Dispatch: A method to send an action to the store.
5. Selectors: Functions to retrieve specific parts of the state.

Example flow:

dispatch({ type: 'INCREMENT' });
↓
reducer receives action and returns updated state
↓
components subscribed to store update accordingly

It’s unidirectional and predictable—no surprises.

🎯 Why use redux?

Redux solves several common problems in larger applications:

✅ Centralized state

Everything lives in one place, making debugging and testing easier.

🔁 Predictable state transitions

Reducers are pure functions, so given the same state and action, the outcome is always the same.

🧪 Time travel debugging

With tools like Redux DevTools, you can inspect past actions, step back and forward, and replay state transitions.

🔌 Ecosystem

Redux has a mature ecosystem: middleware support, async handling (e.g. redux-thunk, redux-saga), and strong dev tooling.

📦 Redux toolkit: the modern way

Redux Toolkit (RTK) is now the standard approach for writing Redux logic. It simplifies boilerplate and encourages best practices:

import { createSlice } from '@reduxjs/toolkit';

const counterSlice = createSlice({
  name: 'counter',
  initialState: 0,
  reducers: {
    increment: state => state + 1,
    decrement: state => state - 1
  }
});

export const { increment, decrement } = counterSlice.actions;
export default counterSlice.reducer;

You no longer need to write action creators and reducers separately. RTK also supports async logic with createAsyncThunk.

🧠 When should you use redux?

Redux is useful when:

• You have complex state logic shared across many components.
• You need global state like auth, settings, or theme.
• You want fine-grained control over how state is updated.
• You’re building a large-scale application with many developers.

Examples:

• Multi-step forms
• E-commerce carts
• Dashboards with filters, sorting, and data sync
• Admin panels with role-based access

⚠️ When not to use redux

Redux adds complexity, so it’s not always the right choice. You may not need it if:

• Your app is small or medium-sized
• You're only managing local component state
• You prefer simpler solutions like React’s useContext or useReducer

In many cases, React Query, Zustand, or even just useState are more than enough.

🔄 Alternatives to redux

✅ Summary checklist

• ✅ Use Redux for large, state-heavy applications
• ✅ Prefer Redux Toolkit to reduce boilerplate
• ✅ Avoid Redux for simple/local state
• ✅ Combine Redux with tools like React Query when needed
• ✅ Use DevTools to debug and inspect app state

🧠 Conclusion

Redux is a powerful tool—but it’s not always necessary. With Redux Toolkit, managing complex state becomes more approachable and scalable. If your app is growing and you need a solid, predictable way to handle state, Redux is still a great choice.

As with any tool, the key is using it when it add value, not just out of habit.