Signals in Django are a way to allow decoupled applications to get notified when certain actions occur elsewhere in the application, such as saving a model instance.

Signals in Django provide a powerful mechanism for decoupled applications to communicate and respond to events that occur within the application. They allow developers to define certain actions that should be triggered automatically when specific events happen, such as saving a model instance or user logging in. Django provides a set of built-in signals, such as pre_save, post_save, and pre_delete, that can be connected to custom functions, known as signal handlers. When the specified event occurs, the associated signal handler is automatically executed, enabling developers to perform additional logic, such as sending notifications, updating related models, or logging actions. Using signals promotes clean and maintainable code, as it allows different parts of the application to remain decoupled while still responding to changes. However, developers should use signals judiciously, as overusing them can lead to complex interdependencies and make the codebase harder to understand. By leveraging Django signals effectively, developers can create more responsive and flexible applications that react dynamically to user actions and system events.