When Expel was founded, we had the goal of making our platform “flypaper for inventors.” What this means is that, if you have an idea, you should be able to safely test it out on top of our platform using existing technology levers (in this case APIs).
The Expel Workbench is JSON API compliant and uses swagger for API specification/documentation. You can find the Expel swagger doc here. Pyexclient is the python-ification of the JSON API spec. The pyexclient client code, and much of the documentation, is auto generated from swagger spec file.