We have a sample .vbs script which uses the web API within the core Kartris zip, located here:

/Protected/KartrisWebAPISample.vbs

Obviously you don't have to use VBscript. This is a SOAP interface, so you can use .NET, php, Javascript, Java, or whatever.

A Kartris developer POLYCHROME has also kindly donated some sample extension code, 'helper' classes which may be useful to help illustrate how to extend Kartris's BLL for use via the web API for your specific application.

Sample code for extending Kartris with helper classes to use via the web API