“App” or “application” are commonly used terms for computer programs which provide a non-system technical function. This application software can be distinguished from data or documents as well as from system software. However, the latter differentiation is not always precise, especially with today’s modular systems.

For example, a common Linux distribution consists of a mixture of system software, the so-called kernel, and sometimes of thousands of applications, which provide more or less system-related functions.

Colloquially, the term “app” is mainly used for a “mobile app”, i.e. an application for mobile devices such as smartphones and tablet computers. However, some applications for desktop systems are now also called “apps”, for example in Microsoft’s operating system Windows. Likewise, an increasing number of devices offer the possibility to extend or add functions by way of apps, e.g. printers.

Mobile payment apps are common in the area of payments. However, it can be increasingly observed that the devices located at the POS are also equipped with apps. For example, cash register systems as well as payment terminals can nowadays be extended with apps for the integration of loyalty systems, the creation of vouchers or the brokerage of consumer credits.