I have succesfully imported the openXML files with the help of API-reference & How to article.
API-client is requiring "nodeurl" to point out the destination of imported entities. In the API-reference's example the nodeurl was following:
What is the nodeurl for importing entities to POUs-tab instead of Devices-tab?
Solved! Go to Solution.
I did some test and found that it is at the moment not possible to import xml files to to the root of the POUs via the REST API of the ctrlX PLC Engineering. You will have to add a parent folder and import into this one: