Hi @harry_wood, thanks for using the API notebook.
You might have found a bug inside the notebook. Can you report it into our Github repo here. It seems that the object after "stops" does contain the two sub-resources, but the notebook has some problems with either using
near.json. Our team can have a look at that after you raised it.
Regarding the more generic JS playground. I am sure that you can use any JS, but not very sure about things that need additional libraries like jQuery or Ajax. Have you tried looking at the standalone version? Maybe there is a possibility to host it with additional capabilities.