https://developers.arcgis.com/documentation/mapping-apis-and-location-services/
https://route.arcgis.com/arcgis/rest/services/World/Route/NAServer/Route_World/solve?stops=-117.1956,34.0564;-117.1825,34.0572&token=[token]&f=pjson
REST API access is not just for basic "Location Services"
REST API covers all of web-accessible ArcGIS
community.esri.com
By Jim Barry