Feeds Node processor mapping
Does the Node processor mapping require a unique identifier for the GUID or is this not mandatory?
You do not need to have a unique identifier to import data, but you might get duplicate data if you do not use a unique identifier.  From your question I assume you are interacting with the API in the feeds fetcher. Can you get &quot;duplicate&quot; results when using the API? Or, is each import ALWAYS  creating new nodes?
Xpath
Use //content/text() to return the json text {&quot;appointmentSet&quot;:[{&quot;appts&quot;:[]}],&quot;bookingAllowed&quot;:false,&quot;maxBookAheadPeriod&quot;:25}