This is a question that we hear frequently since we have released Exchange 2007. And our answer has to be heard loud and clear: going forward Exchange Web Services should be the API of choice for developers.
Already a year ago at TechEd 2006 we announced that the ExoleDB, WebDAV and CDOEx (APIs that we have shipped since Exchange 2000) would be de-emphasized in Exchange 2007. We explained that Exchange Web Services were our vision for the future of Exchange application development. this year at TechEd we would like to reinforce that message. This way we hope you will have ample time to migrate your applications to Exchange Web Services. And we would like to invite you to give us as much feedback as possible on this new set of Exchange WebServices APIs. We want to make sure that in order to enable you to do all that the old APIs could do and do this in one consistent set of APIs that are easy to understand and provide you all you need in order to build your applications on top of Exchange..
In past releases deciding which Exchange API to use for a project required using a complex matrix of requirements versus feature sets to determine which API was the right choice from the smorgasbord of API offerings that we provided. This all has changed in Exchange 2007 when we made a commitment to simplify our developer’s lives for the better. That commitment was to develop an API that could grow to meet all of our customer’s requirements for a PIM access API. These requirements included: full support in managed code, strongly typed PIM objects, encapsulation of complex business logic internal to Exchange, remotability, open-standards and cross-platform capable, performant and scalable. The API that we developed in response to this need was Exchange Web Services.
As we promised with the roll-out of Exchange 2007 Web Services we are continuing to invest in making our web services a great developer API for Exchange 2007. Our goal in Exchange 2007 RTM was to get a solid foundation in place and implement the functionality that the majority of Exchange Developers need. We hit the mark, releasing Mail, Calendar, Task, Contact access in Exchange 2007 RTM. With the SP1 release of Exchange Web Services (EWS) we are planning to add a whole host of great features, including Public Folder support, folder permissions support, ID conversion methods for OWA extensibility, (and one of the most exciting features for anyone developing a calendar application on Exchange) full delegate access support! Exchange 2007 SP1 will be very exciting since it now gives Exchange developers an extremely rich array of Exchange features to leverage in building new applications that weren’t easily implemented on Exchange 2003 like complex scheduling and calendaring applications with meeting request work flow.
We highly recommend that you use Exchange Web Services for new application development and avoid ExoleDB, WebDAV and CDOEx for new development. Give us feedback on about what you like and dislike in the API and what features you would prioritize next. We realize that building the new API set is a work in progress and we are aware that we haven’t yet implemented some of the features that you developers might need for your applications. Yet we are openly looking for your feedback knowing that that feedback will help us on prioritizing the new features we are adding. If there is some functionality you need that isn’t yet in EWS, and neither will be there in the next release, then let us know through the Exchange Developer Blog or Exchange Developer Newsgroup, we are always reading those for the great feedback you customers can provide us.
Some great resources to get you started with Exchange Web Services development are the Exchange Web Services MSDN reference documentation, the Exchange Developer Newsgroup, the Exchange Development Center and the Exchange Developer Blog.
The EWS Team