Apple Push Notification Service (APNS) is a service from Apple that enables a user or service to send push notification messages to Apple iOS and Mac OS X apps. APNS debuted for the Apple iPhone with the release of Apple’s iOS 3 update in June 2009.
The Apple Push Notification Service has since been added as an API (application program interface) to the Mac OS X operating system as of the 10.7 “Lion” release. Apple refined its APNS support on Mac OS X in 2012 with the addition of the Notification Center in the 10.8 “Mountain Lion” operating system release.
How the Apple Push Notification Service Works
The Apple Push Notification Service comes into play when software developers first originate notifications in their server software. These servers connect with the APNS through a persistent and secure channel to send the encrypted notifications to their target devices.
Each APNS notification is a short message that consists of a device token and the payload. The device token is an identifier that enables the APNS to route the notification to the intended device, and the payload is a JSON-defined property that contains the information in the notification as well as how the user of the device will be alerted.
APNS notifications can take the form of sounds, badges (a number placed on the app icon to reflect updated information within the app) or text alerts that are displayed to the user.
How to Create Your Own APNS Messages
Developers interested in creating their own Apple Push Notification Service messages can get started by first creating an Apple developer account and registering an iOS device and then creating an iOS Provisioning Profile. Apple has released the Apple Local and Push Notification Programming Guide to further guide developers in creating and sending their own APNS messages.