Outbound services define how outbound voice and fax calls are to be handled. They define the application (REST or UAS) that is going to manage the call.
You can create, configure and delete outbound services using the Cloud Console or use the outbound services Management API.
To Start an outbound service you use a web API and specify the destination and other details of the outbound call.
Requests to start an outbound service are queued as several may be made concurrently. You can monitor and manage the queue for each service on the Cloud Console or via the Queues API.