MAPI (Messaging Application Programming Interface)

The API that is used by Microsoft messaging applications such as Outlook to access collaboration data. MAPI, or more specifically, MAPI Remote Procedure Calls (RPC), is also used as the transport protocol between Outlook clients and servers running Exchange. [Exchange 2000]

The application programming interface (API) for which Active Directory provides support for backward compatibility with Microsoft Exchange applications. New applications should use Active Directory Service Interfaces (ADSI) for accessing Active Directory. [Exchange 2003]

A messaging architecture that enables multiple applications to interact with different messaging systems across a variety of hardware platforms. MAPI is built on the Component Object Model (COM) architecture. [Exchange 2007]

A standard interface that Exchange and Microsoft Outlook components use to communicate with one another. [Exchange 5.5]