Interfacing mechanisms of existing programming interfaces (PIs) could be applied to an Aerospace Design Representation Programming Interface (AERO-DRPI). Therefore it is necessary to study representative PI(s) to examine their features and their potential influence on specifying an AERO-DRPI.In our view the abstraction level of functionality categorizes interfacing mechanisms into three types. The first provides fundamental interfacing functionality that is reused by other types of interfaces. The second provides generic design management interfacing functionality and the third provides specific design management interfacing functionality.Representative PI(s) are analyzed by examining how well they meet our AERO-DRPI requirements. From this analysis we extract important characteristics of PI mechanisms that could be applied to an AERO-DRPI.