An event represents that something meaningful happened in the application, such as an order being placed or a user registering. A listener is a class that reacts to that event, for example by sending a notification, updating a search index, or dispatching a follow-up job.

This pattern decouples the code that performs the original action from optional side effects. Laravel resolves listeners through the service container, can queue eligible listeners, and supports automatic event discovery or explicit registration. Events should describe facts that occurred, not become a hidden substitute for essential synchronous business flow.