What is the Flux architecture pattern?

Flux is Facebook's application architecture pattern that Redux is based on. It enforces a strict unidirectional data flow. Components: Action: object describing an event. Dispatcher: central hub that receives all actions and dispatches to registered stores. Store: holds application state and logic, responds to actions from the dispatcher. View: React components that render state from stores and create actions on user interactions. Flow: User interaction → Action → Dispatcher → Store (state update) → View re-render. Redux simplification: Redux replaced the Dispatcher with a single reducer function, stores multiple states in a single object, and eliminated the need for multiple stores. Redux is often called "Flux done right." Why Flux/Redux: traditional MVC breaks down when complex applications have many components sharing state — circular data flows and cascading updates make debugging impossible. Flux's unidirectional flow makes the application state predictable: for any action, you know exactly which store changes and how.