A system-level alert on Apple’s mobile operating system that allows applications to send timely and relevant information to users even when the app is not actively running. These alerts can appear as banners, alerts in the Notification Center, or badges on app icons. For example, a news application might use this mechanism to inform users of breaking news headlines, or a social media application could alert a user about new messages or friend requests.
This functionality is crucial for enhancing user engagement and delivering immediate updates. Its implementation represents a significant advancement in mobile communication, shifting the interaction paradigm from user-initiated polling to proactive information delivery. Originally introduced to improve battery life by reducing the need for constant application checks, it has become a central feature for user experience and application functionality.