Messaging Application Programming Interface (MAPI) is an

API An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software Interface (computing), interface, offering a service to other pieces of software. A document or standa ...

for

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

which allows programs to become

email Electronic mail (email or e-mail) is a method of exchanging messages ("mail") between people using electronic devices. Email was thus conceived as the electronic ( digital) version of, or counterpart to, mail, at a time when "mail" meant ...

-aware. While MAPI is designed to be independent of the protocol, it is usually used to communicate with Microsoft Exchange Server.

Details

MAPI uses functions loosely based on the

X.400 X.400 is a suite of ITU-T Recommendations that defines the ITU-T Message Handling System (MHS). At one time, the designers of X.400 were expecting it to be the predominant form of email, but this role has been taken by the SMTP-based Internet e-m ...

XAPIA standard. It includes facilities to access message transports, message stores, and directories. While ''Simple MAPI'' (SMAPI) is a subset of 12 functions which enable developers to add basic messaging functionality, ''Extended MAPI'' (EMAPI) allows complete control over the messaging system on the client computer. This includes creation and management of messages, plus management of the client mailbox, and service providers. Simple MAPI is included with

as part of Outlook Express/ Windows Mail while the full Extended MAPI is included with

Microsoft Outlook Microsoft Outlook is a personal information manager software system from Microsoft, available as a part of the Microsoft Office and Microsoft 365 software suites. Though primarily an email client, Outlook also includes such functions as Calen ...

and Exchange. In addition to the Extended MAPI client interface, programming calls can be made indirectly through the Simple MAPI API client interface, 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. (Simple MAPI and CMC were removed from Exchange 2003.) MAPI was originally designed by

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washing ...

. The company founded its MS Mail team in 1987, but it was not until it acquired

Consumers Software Consumers Software was a computer networking company based in Canada. The company created early spreadsheet utilities and later developed Network Courier, an email product based on the concept of one or more connected 'post offices'. The post offi ...

in 1991 to obtain ''Network Courier'' that it had a messaging product. Reworked, it was sold as MS PC Mail (or

Microsoft Mail Microsoft Mail (or MSMail/MSM) was the name given to several early Microsoft e-mail products for local area networks, primarily two architectures: one for Macintosh networks, and one for PC architecture-based LANs. All were eventually replaced b ...

for PC Networking). The basic API to MS PC Mail was later known as MAPI version 0 (or ''MAPI0''), to differentiate it from "true" MAPI.

Service provider interface

The full Extended MAPI interface is required for interfacing messaging-based services to client applications such as Outlook. For example, several non-Microsoft e-mail server product vendors created "MAPI service providers" to allow their products to be accessed via Outlook. Notable examples include Axigen Mail Server,

Kerio Connect Kerio Technologies, Inc. is a former technology company specializing in collaboration software and unified threat management for small and medium organizations. Founded in 2001, Kerio is headquartered in San Jose, California. In January 2017, GFI ...

, Scalix,

Zimbra Zimbra Collaboration, formerly known as the Zimbra Collaboration Suite (ZCS) before 2019, is a collaborative software suite that includes an email server and a web client. Zimbra was initially developed by LiquidSys, which changed their name ...

, HP OpenMail, IBM Lotus Notes, Zarafa/ Kopano, and Bynari. MAPI also had a service provider interface of sorts. Microsoft used this to interface MS Mail to an email system based on

Xenix Xenix is a discontinued version of the Unix operating system for various microcomputer platforms, licensed by Microsoft from AT&T Corporation in the late 1970s. The Santa Cruz Operation (SCO) later acquired exclusive rights to the software, and ...

, for internal use. Extended MAPI is the main e-mail data access method used by Outlook, to interface to Microsoft Exchange, via MAPI service providers shipped with Outlook.

MAPI/RPC protocol details

Microsoft has released full details of the MAPI/RPC protocol since August 2007. "MAPI protocol" is a colloquial name for the MAPI/RPC. At times, Microsoft has also called it "Exchange RPC" and "Outlook-Exchange Transport Protocol". Microsoft provides a sample MAPI/RPC-based application called MFCMAPI to assist developers. It is also widely used as a diagnostics tool by both developers and Microsoft Exchange administrators.

MAPI over HTTP

The original implementation was designed for use on a local network, or

LAN Lan or LAN may also refer to: Science and technology * Local asymptotic normality, a fundamental property of regular models in statistics * Longitude of the ascending node, one of the orbital elements used to specify the orbit of an object in sp ...

. With Exchange 2003 Microsoft introduced RPC over HTTP (later renamed Outlook Anywhere) as a way to Exchange over the internet. In 2014 with Exchange 2013 SP1 replaced this with a more 'normal' HTTP-based stack known as "MAPI over HTTP".

Reimplementations

Several

open-source software project Open-source software development (OSSD) is the process by which open-source software, or similar software whose source code is publicly available, is developed by an open-source software project. These are software products available with its sourc ...

s have started working on implementing MAPI libraries, including: * The OpenMapi project (now demised) had a C# implementation. * Kopano (software) Groupware Core has a C++2011 implementation called "mapi4linux" (continuation of the same from Zarafa), which offers an API that is source-backwards-compatible with the Messaging API (code written for M4L also build with the Windows SDK). Kopano GWC comes with a connector for the Zarafa/Kopano-based SOAP/HTTP transport. * OpenChange has a "libmapi" component written in C that only partially resembles MAPI. (Lacks interfaces like IMsgStore, the OpenEntry function.) * The OpenChange subproject Evolution-MAPI is a connector for Exchange implementing the MAPI/RPC transport. * The Gnome Evolution project develops ''evolution-ews'', which has implemented much of MAPI.

References

External links

Messaging API at MSDN LibraryOpenChange project - details of MAPI protocol and tools for exploring MAPI protocolOpenMapi project - Open Source, multi-language MAPI implementation which can connect to other groupware sources, with API documentationMessaging API Archived User ForumEnabling Outlook Connector logging for support
{{Microsoft APIs Internet mail protocols Microsoft application programming interfaces