The Apple Push Notification Service is a service created by Apple Inc. that was launched together with iOS 3.0 on June 17, 2009. It uses push technology through a constantly-open IP connection to forward notifications from the servers of third party applications to the Apple devices; such notifications may include badges, sounds or custom text alerts. APNS was also added as an API to Mac OS X v10.7 "Lion" for developers to take advantage of.
Apple first announced the service on 9 June 2008 with a stated release for that September; however, as stated by Scott Forstall at the iOS 3.0 preview event on 17 March 2009, the rollout was delayed after a decision to restructure the APNS for scalability purposes due to the allegedly "overwhelming" response to the announcement of the APNS. At both events, Forstall stated that push notifications were a better means to maintain battery life than background processes (which are used for pull technology) as far as receiving notifications are concerned.
With Mac OS X Lion, an app can take advantage of the same API used in iOS to push badge numbers to applications running on Mac OS X. With the release of OS X Mountain Lion, users can receive push notifications through Notification Center. If the application is not open when the notification is received, the app will be badged and added to the dock (until the badge is cleared) to notify users.
APNS is used together with Mac OS X Lion Server to push update notifications to clients that have registered to receive updates via a configuration profile and are also using the server's mail, calendar and contacts services. This means that devices such as the iPhone and applications like iCal on the Mac can receive a notification.
Each notification has a maximum size of 256 bytes, which makes it very efficient for services with small data allowances (such as mobile phones).
es:Apple Push Notification Service pt:Apple Push Notification Service ru: Push Apple uk:Push