EWS Managed API 2.0

https://msdn.microsoft.com/en-us/library/office/dd633709.aspx

Applies to: EWS Managed API

The Exchange Web Services (EWS) Managed API provides a simple and full-featured interface for developing and extending applications that use EWS. You can use the EWS Managed API to access EWS in versions of Exchange starting with Exchange Server 2007 Service Pack 1 (SP1), including Exchange Online.

The EWS Managed API provides user-friendly abstractions of XML messages, XML serialization, and the formation of the HTTP requests and responses that are sent between the client and server.

You can download the EWS Managed API from the Microsoft Download Center.