Exchange Web Services (EWS)

Exchange Web Services (EWS) is an application program interface (API) that allows programmers to access Microsoft Exchange items such as calendars, contacts and email.  

EWS, which first became available in Exchange Server 2007, provides administrators with the flexibility to store, retrieve, move and modify email and related data for a single user, a group of users or an entire Exchange Server organization on an Exchange server. EWS can be useful for migrating Exchange data on-premises or to a third-party host in the cloud.

See also: Messaging Application Programming Interface (MAPI), Simple Object Access Protocol (SOAP)