Redux is a state management library for JavaScript applications, commonly used with frameworks like React. It follows a unidirectional data flow pattern and helps manage the state of an application in a predictable and centralized manner. Redux stores the entire application state in a single JavaScript object called the store. Actions are dispatched to update the state, and reducers specify how the state should be modified in response to those actions. Components can subscribe to the store and receive updates whenever the state changes, allowing them to re-render accordingly. This centralized approach to state management in Redux makes it easier to understand, test, and maintain complex applications.