What is Microsoft Exchange, MAPI, and Exchange ActiveSync?
Microsoft began developing MAPI (sometimes called Messaging API) not long after IMAP and POP were first developed, although it has uses beyond simple email. Thoroughly comparing IMAP and POP to MAPI is pretty technical, and out of scope for many readers of this article. Simply put, MAPI is a way for applications and email clients to communicate with Microsoft Exchange servers, and is capable of IMAP style syncing of emails, contacts, calendars, and other features, all tied into local email clients or applications. This function of syncing emails is branded by Microsoft as ?Exchange ActiveSync.? Depending on what device, phone, or client you use, this same technology might be called any of the three Microsoft products (Microsoft Exchange, MAPI, or Exchange ActiveSync), but will offer the same cloud-based email syncing as IMAP.
Because Exchange and MAPI are Microsoft products, only companies that own their own Exchange mail servers or use Windows Live Hotmail will be able to use Exchange. Many clients, including the default Android mail client and iPhone, are Exchange ActiveSync capable, giving Hotmail users IMAP style cloud-based email, despite Hotmail not offering true IMAP functionality.