Several configuration APIs allow you to manage the system, users, devices and features.
Configuration APIs exist in both SOAP and REST protocol formats and are mutually exclusive of each other. It is however possible to use both formats in conjunction depending on what you are aiming to achieve.
Not all of what is available from the Configuration Administration Web interface or the User Web Portal is available for extensions using web services. If an API does not exist, you have the possibility to create one to suit your needs.
In addition, the HTML that is returned makes common use of the HTML ID attribute to uniquely identifiable key parts of the page to the unit tests. These same IDs can be found by XPath or even XML DOM navigation parsing libraries fairly easily.
If you decide to go this route, consider expanding on the Web Service APIs as well and submitting your changes back to sipXcom upstream. Web pages are subject to change and do not constitute a stable API like the Web Service APIs would.
The result of the queries are description in JSON and/or XML format.