Redux Thunk vs Redux Saga: Which One Should You Use?

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If you’re working with Redux, you’ve probably faced the challenge of handling asynchronous operations like fetching data from an API. Since Redux only supports synchronous updates by default, middleware like Redux Thunk and Redux Saga come into play. But which one should you use? While Redux Thunk is simple and easy to implement, Redux Saga offers powerful control over complex side effects.

Let’s break down their differences and see which one best fits your needs.

Both Redux Thunk and Redux Saga are middleware for handling asynchronous logic in a Redux application, but they serve different purposes and have different use cases.

Use Redux Thunk When:

• You need a simple, lightweight solution – Thunk is just a function that returns another function, making it easy to use and understand.
• Your async logic is straightforward – If you’re just making API calls and dispatching actions, Thunk is sufficient.
• You don’t need advanced async workflows – Thunk doesn’t handle complex side effects like race conditions or cancellations well.
• You prefer writing async logic inside action creators – Since Thunk allows returning a function, you can write async API calls directly in your action creators.

const fetchUser = (userId) => {
  return async (dispatch) => {
    dispatch({ type: 'FETCH_USER_REQUEST' });
    try {
      const response = await fetch(`/api/users/${userId}`);
      const data = await response.json();
      dispatch({ type: 'FETCH_USER_SUCCESS', payload: data });
    } catch (error) {
      dispatch({ type: 'FETCH_USER_FAILURE', error });
    }
  };
};

Use Redux Saga When:

• You need to handle complex async workflows – Saga is powerful for handling race conditions, retry logic, and complex async tasks.
• You need better control over side effects – Saga uses generators (function*), making it easier to manage async flows in a structured way.
• You need to listen to actions in the background – With Saga, you can create background processes that respond to specific actions.
• You need better error handling and cancellation – Saga provides built-in mechanisms to cancel API calls, retry failed requests, and debounce actions.

import { call, put, takeLatest } from 'redux-saga/effects';

function* fetchUserSaga(action) {
  try {
    const response = yield call(fetch, `/api/users/${action.payload}`);
    const data = yield response.json();
    yield put({ type: 'FETCH_USER_SUCCESS', payload: data });
  } catch (error) {
    yield put({ type: 'FETCH_USER_FAILURE', error });
  }
}

function* watchFetchUser() {
  yield takeLatest('FETCH_USER_REQUEST', fetchUserSaga);
}

Which One to Choose?

Use Redux Thunk if you have a simple use case with basic async API calls.

Use Redux Saga if you need advanced async flows like handling background tasks, complex error handling, retries, debouncing, or handling multiple API calls simultaneously.

For most small to medium projects, Redux Thunk is enough. But if your app requires complex async logic, Redux Saga is a better choice.