This reference document lists and describes all the dimensions and metrics available through the Real Time Reporting API.
Dimensions
rt:userType
A string value indicating if a user is new or returning. Possible values
are NEW
and RETURNING
.
Metrics
rt:activeUsers
The number of users interacting with the property right now.
Not all dimensions and metrics can be queried together. Review the Query Constraints section in the Dev Guide for additional details.