In addition, an XPC service that you include with your app is accessible only by your app. Each service gets its own sandbox-specifically, it gets its own container and its own set of entitlements. You create an XPC service as an individual target in your Xcode project.

The component pieces that you create are called XPC services. Privilege separation, in turn, is a development strategy in which you divide an app into pieces according to the system resource access that each piece needs. XPC is an OS X interprocess communication technology that complements App Sandbox by enabling privilege separation. XPC Interprocess Communication and Services The following sections describe features in the Kernel and Device Drivers layer of OS X. OS X extends this low-level environment with several core infrastructure technologies that make it easier for you to develop software. The lowest layer of OS X includes the kernel, drivers, and BSD portions of the system and is based primarily on open source technologies.