Push notifications, or Apple Notification Services (APNs), are a mechanism for third-party developers to send notifications as packets of data to users who have their applications installed on their devices. Notifications display and notify the users, subtly, of important and time-sensitive news items. Displaying a transient bar in the top part of the screen, along with a nominated notification sound, notifications deliver a short message, as well as optional actions the users can take without being required to open the app.
Take a push notification from the Facebook Messenger (https://facebook.com). When a user sends a message to a friend, the friend receives a push notification with an excerpt of the message and a bell sound notifying the user. The following screenshot illustrates an icon when a new, unread notification is received, showing a badge-count on the top-right corner:
Along with the option to reply directly from within the notification widget, bypassing...
