Hi
Right now im testing this one just to get the logic to work in my head:
Rest API:
Invoke-RestMethod http://localhost:5000/scripts123 -Method POST UseDefaultCredentials -Body ‘{“ADUserName” : “myUserName”, “UserDomain” : “myDomain”}’ -ContentType ‘application/json’
Endpoint code:
Get-Aduser -Identity $ADUserName
Found this thread and im not sure if it should even work like this 
thanks