About Client Extensions

Using the Client Extensions Programmer's Reference, it is possible to develop a wide variety of custom client applications that access Microsoft Exchange services such as the information store. These custom client applications can provide different views of data in the information store, data searching and sorting capabilities, security, custom mail or messaging features, forms, workgroup capabilities, and many other capabilities.

This documentation describes the four types of Microsoft Exchange client extensions in the following topics:

You can also develop multi-purpose extensions that span two or more of these categories. For example, you can develop an extension that adds menus to the Microsoft Exchange Viewer window and also provides custom property sheets.

This section provides detailed information on how the Microsoft Exchange client interacts with the major categories of extensions. Information is also provided on how to write modeless extensions, how to register extensions depending on your operating system, and how to optimize performance.

Note For sample code illustrating some of the concepts covered in this section, see the Code Samples section in the Platform SDK.