MAPI is an acronym for Messaging Application Programming Interface. MAPI allows client programs to become (electronic mail) messaging-enabled, -aware, or -based by calling MAPI subsystem routines that interface with certain messaging systems and message stores (MAPI has its own temporary store in the MAPI spooler). API with 3 clients, using the Unified Modeling Language notation An application programming interface (API) is a set of definitions of the ways one piece of computer software communicates with another. ... Electronic mail, abbreviated e-mail or email, is a method of composing, sending, and receiving messages over electronic communication systems. ... A remote procedure call (RPC) is a protocol that allows a computer program running on one host to cause code to be executed on another host without the programmer needing to explicitly code for this. ...

As well as the main MAPI client interface, programming links can be made indirectly through the API client interface Simple MAPI, or through the Common Messaging Calls (CMC) API client interface, or by the object-based CDO Library interface. These three methods are easier to use and designed for less complex messaging-enabled and -aware applications. The full MAPI interface is required for messaging-based applications.

MAPI was originally designed by Microsoft. The company founded its MS Mail team in 1987, but it was not until it acquired Consumers Software Inc in 1991 to obtain Network Courier that it had a messaging product. Reworked it was sold as MS PC Mail (or Microsoft Mail for PC Networking). The basic API to MS PC Mail was MAPI version 0. MAPI uses functions based on the X.400 XAPIA standard. Microsoft Corporation (NASDAQ: MSFT) is the worlds largest software company, with over 50,000 employees in various countries as of May 2004. ... 1987 is a common year starting on Thursday of the Gregorian calendar. ... 1991 is a common year starting on Tuesday of the Gregorian calendar. ... In computing, X.400 is a OSI standard developed by the ITU-T (at the time the CCITT) and promulgated by ISO for the exchange of email (at the time called IPMs - Inter Personal Messages). ... XAPIA is an acronym for the X 4. ...

MAPI was the main e-mail data access method used by Microsoft until Exchange 5.5, by the Exchange Data Objects (EDO) and Collaboration Data Objects (CDO) interfaces. Exchange 2000 greatly expanded the supported services, notably with MAPI-compliant LDAP. Simple MAPI and CMC were removed from Exchange 2003. Microsoft Exchange Server is a collaborative software server from Microsoft, positioned as a rival to the Lotus Notes / Domino server from IBM and recently challenged by a number of Linux-based competitors, first and foremost Scalix. ... Lightweight Directory Access Protocol (LDAP) is a protocol for accessing on-line directory services. ...

In light of the existence of open messaging standards such as SMTP and IMAP, MAPI is sometimes criticized as an illustration of Microsoft's "Embrace, extend and extinguish" approach to internet protocols. Simple Mail Transfer Protocol (SMTP) is the de facto standard for email transmission across the Internet. ... The Internet Message Access Protocol (commonly known as IMAP, and previously called Interactive Mail Access Protocol) is an application layer Internet protocol used for accessing email on a remote server from a local client. ... Microsoft has publicly stated that it aims to embrace and extend popular standards and existing work. ...

External link

• Messaging API at MSDN Library