OnApp works with HostBill, Ubersmith, and WHMCS. We develop and maintain the WHMCS modules and support them directly. HostBill and Ubersmith modules are supported directly by the vendor and are natively included with the relevant software.
If you have a full OnApp license, we can assist you with questions regarding the supported billing modules and provide support with OnApp's WHMCS integration modules.
For assistance with HostBill and Ubersmith integrations, please contact the vendors directly.