The services resource represents the list of services installed on the Domino server. Domino 9.0.1 includes three services -- Core, Data and Calendar -- but other services can be added to a Domino server. For example, other services are included in the extension library on OpenNTF (http://extlib.openntf.org).
When you send a GET request to the services resource, the response is an array of services in JSON format. Each service has a property indicating whether it is enabled on the server. Each service also includes a version number and a link (href) to its root resource.