The Events API returns information about all or selected events. The returned data includes ConfirmedRegistrationsCount and RegistrationsLimit. It would be very helpful to have the API call also return the count of people on the waitlist.
The Export registrants option in the Admin section doesn't include registration limits.
Currently, I have to fetch each event and count the number of people on the waitlist for each event. That's a lot of loops. We have a few hundred events to mung.