Redux

Redux is a library for global state in which the whole app’s shared data lives in one store, and the only way to change it is to dispatch an action that a reducer turns into new state. In React Native it works exactly as on the web, connected to components through react-redux.

Redux Toolkit (RTK) is the official way to write Redux today. It replaces the hand-written action types, switch statements and immutable spread updates of older tutorials with configureStore and createSlice, and it uses Immer so reducers can look like mutations:

const cartSlice = createSlice({
  name: 'cart',
  initialState: { items: [] as string[] },
  reducers: {
    added(state, action: PayloadAction<string>) {
      state.items.push(action.payload);
    },
  },
});

Components read with useSelector and write with useDispatch. RTK also ships RTK Query, a data-fetching and caching layer comparable to TanStack Query, which is the right place for API data if you are already on Redux.

Why teams still choose it: strict, traceable updates, middleware for side effects, and excellent time-travel debugging, which in React Native usually means a tool such as Reactotron. Large teams value the enforced structure. For a small app, a lighter store like Zustand is often enough.

The common performance gotcha is a selector that returns a new object or array on every call, for example useSelector((s) => s.items.filter(...)). Because the result is never referentially equal, every dispatch anywhere in the app re-renders that component. Use memoised selectors (createSelector) or select primitives. The second gotcha is persistence: on mobile the store is wiped when the app is killed, so anything that must survive a restart needs explicit persistence to device storage, and that layer then needs migrations when the state shape changes. See the Redux Toolkit docs.