Apple Push Notification Service (APNs for short), launched together with iOS 3.0 on June 17, 2009, is the core of the push notifications element. It is highly resourceful means for distributing information to iOS and OS X devices. Every device sets up a recognized and encrypted IP connection with the service and takes delivery of notifications over this continual 
connection. If a notification for an application reaches when that application is not running, the device alerts the user that the application has data, which can be reviewed. 

Mobile app developers create the notifications in their server software. The function of the provider is to watch for the incoming data for the applications installed by their customers. 

When it comes, the provider connects with APNs through a persistent and secure channel while monitoring incoming data intended for their client applications. When new data for an application arrives, the provider prepares and flings a notification through the channel to APNs Subsequently the APNs push the notification to the intended device. APN stores and sends the notifications may be in the forms of badges, sounds or custom text alerts. 

To iphone app developer, it is easy to get your application receive notifications. But sending messages need a little more efforts and planning. Code snippets and expert instructions for this feat are separate. Native iPhone application developers will be well-experienced in 
configuring Cron Job, incorporating APNs to Apple Delegate files. They can also implement APN service with Play framework. 

Regarding Author:

Author is a senior business analyst and an expert in native mobile app development.

Resources: 
http://www.mobileapptelligence.com
http://www.mobileapptelligence.com/android-app-developer.html 
http://www.mobileapptelligence.com/mobile-app developers.html