An application programming interface (API) includes functions, messages, data structures, data types, and statements that programmers use to create applications that run in the Microsoft Windows operating system. In a way that is similar to users interacting with an application using a graphical user interface, many applications use APIs with which other applications can interact.

Because Microsoft Office Live Small Business is built on Microsoft Windows SharePoint Services 3.0, the APIs in Windows SharePoint Services are as important to developers as those included with Office Live Small Business. However, not all the APIs (or features) of Windows SharePoint Services 3.0 can be used with Office Live Small Business, and some Windows SharePoint Services APIs are blocked.

For information about the features of Windows SharePoint Services that are used in Office Live Small Business, see About Windows SharePoint Services 3.0 Features Used in Office Live Small Business.

For information about which Windows SharePoint Services APIs are used in Office Live Small Business and which are blocked, see Working with Windows SharePoint Services 3.0 Web Services.