API support is not available on ZoneDirector.
Northbound interface is limited to eDPSK.
From the user guide:
"The Northbound Portal interface allows the use of DPSKs on open WLANs meant for public access.
By enabling the Northbound Portal Interface, a wireless service provider can provide simple but secure Wi-Fi access without account setup or ZoneDirector redirects requests to an outside portal. If access is granted, ZoneDirector provides a unique dynamic PSK. The DPSK can be delivered in a prov.exe which the user’s device with the relevant wireless or displayed on the portal screen for manual entry."