What does Redux Toolkit (RTK) provide over classic Redux?

Question

Accepted Answer

**Redux Toolkit (RTK)** is the official, recommended way to write Redux today. It eliminates the notorious boilerplate of classic Redux — manual action types, action creators, immutable update logic, store setup — while keeping the same core principles.

## The boilerplate problem RTK solves

```js
// ❌ classic Redux — verbose: action types, creators, switch reducers, manual immutability
const INCREMENT = "counter/increment";
const increment = () => ({ type: INCREMENT });
function reducer(state = { value: 0 }, action) {
  switch (action.type) {
    case INCREMENT: return { ...state, value: state.value + 1 };
    default: return state;
  }
}
```

## RTK: createSlice does it all

```js
import { createSlice, configureStore } from "@reduxjs/toolkit";

export const { increment, incrementBy } = counterSlice.actions; // action creators AUTO-generated
const store = configureStore({ reducer: { counter: counterSlice.reducer } });
```

`createSlice` auto-generates action types and creators, and — via **Immer** — lets you write "mutating" reducer code that's safely converted to immutable updates. One concise slice replaces all the manual pieces.

## What else RTK includes

```text
configureStore   → store setup with DevTools + thunk middleware preconfigured
createAsyncThunk → standard async (pending/fulfilled/rejected actions) for data fetching
createEntityAdapter → normalized state + CRUD reducers for collections
RTK Query        → a full data-fetching/caching layer (like React Query, built into Redux)
```

## createAsyncThunk example

```js
export const fetchUsers = createAsyncThunk("users/fetch", () => api.getUsers());
// auto-dispatches users/fetch/pending | fulfilled | rejected — handle in extraReducers
```

## Why RTK is the standard now

```text
✓ ~75% less code than classic Redux
✓ Immer → no manual immutable spread logic (fewer bugs)
✓ Good defaults (DevTools, thunk) out of the box
✓ Encourages best practices (slices, normalized data)
✓ RTK Query bundles server-state management
```

## Why it matters

Classic Redux's biggest criticism was its boilerplate; RTK directly fixes that, which is why it's now the **official recommendation** and what "using Redux" means in modern codebases.

Understanding `createSlice` (Immer-powered, auto-generated actions), `createAsyncThunk` (async), `createEntityAdapter` (normalization), and RTK Query (server state) is essential for contemporary Redux work — it preserves Redux's predictability while removing the ceremony that drove many teams to alternatives.