By default, Redux's actions are dispatched synchronously, which is a problem for any non-trivial app that needs to communicate with an external API or perform side effects. Redux also allows for middleware that sits between an action being dispatched and the action reaching the reducers.

Is Redux async or sync?

2 Answers. Redux store only supports synchronous data flow (ref). This is what you get by default with createStore(). Asynchronous middleware like redux-thunk or redux-promise wraps the store's dispatch() method and allows you to dispatch something other than actions, for example, functions or Promises.

Is Redux thunk synchronous?

Thunk functions can be used for both asynchronous and synchronous logic. Thunks provide a way to write any reusable logic that needs access to dispatch and getState .