Find number of features in ArcGIS MapServer layer

Question

Given an ArcGIS MapServer layer URL (eg https://gis.dallascityhall.com/wwwgis/rest/services/Sdc_public/Zoning/MapServer/15), how can I find (preferably in JSON format) the number of total features in the layer?

Answer 1

Oh, there is a "return count only" option (returnCountOnly=1) option, so:

.../query?where=1%3D1&returnCountOnly=true&f=json

Returns:

{"count":3634}