The PlayStation App is a software application for the iOS and Android mobile operating systems developed by Sony Computer Entertainment. It allows users to stay connected to the PlayStation Network from tablet and smartphones, and turns mobile devices into a second screen for the PlayStation 4.
The application allows users to view their PSN activity feed, send and receive messages, and use their mobile device as a second screen for use with the PS4. Including,
Purchase content from the PlayStation Store and have it download to the PS4 while you are away from homeAccess PlayStation Music and control tracks, during play or in other leisure timeSend voice messages to friends onlineWatch live streamsBroadcast gameplay full screen and display viewer comments on the second screenDisplay in-game maps on your mobile device as you play on your PS4Turn your smartphone or tablet into an on-screen keyboardUpload a custom profile pictureScan PlayStation Network card numbers or promotion codes
It also provides a news feed, in addition to being able to read and post comments on the PlayStation Blog. The application also allows users to watch embedded videos, and to share news or products on their Facebook, Twitter or email accounts.