Zorba implements the XQC (XQuery C) API which was designed with the goal to create a standardized C API for interfacing with XQuery processors. XQC provides mechanisms to compile and execute XQueries, manage contexts, and provide a basic interface for the XQuery Data Model (XDM). The project is available under the BSD License and is hosted on http://www.sourceforge.net. It is a joint effort between XQilla and the FLWOR Foundation's Zorba Group with the goal to make these two XQuery processor easily exchangable. However, XQC is still in it's early stages. Zorba implements most of the things that are specified in XQC but also deviates from and enhances the XQC specification to some degree. For instance, the following list contains the differences between the current implmentation of Zorba's C API and XQC.
To start with, this documentation provides a set of examples that demonstrate some features.