With the introduction of Exchange Web Services in Microsoft Exchange Server 2007, we began to invest in a broadly capable developer interface. Exchange Web Services is the first Exchange API to expose rich Microsoft Office Outlook interoperability to any application in a strongly-typed, Internet accessible (HTTP-based) programming model. Because the Exchange Web Services interfaces are based on the HTTP, XML, SOAP, and WSDL open standards, developers are free to use any platform they choose for Exchange development and application deployment. Another great advantage of the open standards-based architecture of EWS is that there are many tools on various platforms available for creating programmatic interfaces for SOAP Web services, which makes developing against Exchange much easier than formatting and processing raw XML. In the next version of Exchange, we will continue to invest in Web services by delivering new capabilities that provide a more efficient and optimized interface for Exchange and UC developers.