Application Portability Profile

It contains a selected suite of specifications that defines the interfaces, services, protocols, and data formats for a particular class or domain of applications.

Late 20th century these systems were well on the way to migrating toward computing environments that consist of distributed, heterogeneous, networked applications, databases, and hardware.

The concept emerged of a federal computing environment, that is built on an infrastructure defined by open, consensus-based standards which serve as de facto means of organizing these systems.

[2] An Open System Environment (OSE) encompasses the functionality needed to provide interoperability, portability, and scalability of computerized applications across networks of heterogeneous, multi-vendor hardware/software/communications platforms.

The "Application Portability Profile (APP) - The U.S. Government’s Open System Environment Profile Version 3.0" provides recommendations on a set of industry, Federal, national, international and other specifications that define interfaces, services, protocols, and data formats to support an Open System Environment (OSE).

Application Portability Profile (APP) Service Areas and the Open-system environment reference model (OSE-RM).
The APP addresses the lowest architecture in the NIST Enterprise Architecture Model , i.e., the Delivery System Architecture.