All substantive functionality of Metrici is provided through services. These are programs that take an XML request and produce an XML response. The user interfaces use these services to maintain and retrieve data to show to the user.
Services provides a complete list of available services.
Services are relatively large-grained components. Each service call performs a meaningful action, i.e. you don't need to call lots of services to do something. Each service commits changes to the underlying database.
Permissions are checked on each service call, though most methods of service invocation hide this from the caller.
The response message for a service will always return an errorNumber element, and if this is not zero, an errorDescription.