Inspera Assessment supports a custom interaction API allowing customers to build specialised question types and stimuli elements with JavaScript or other tools such as Maple TA, Geogebra and Desmos, which still can be exchanged through IMS QTI / IMS PCI.
What is a Custom Interaction?
IMS Global defines Portable Custom Interaction (PCI) as a standard way for custom interaction types to be represented and exchanged as part of the Question and Test in a IMS QTI XML.