Hey!! I am WHMCS expert having 5+ years with custom invoice design, custom template, Addons, Registrar module, Provisioning module and gateway in my past years experience.
-whmcs server modules development
-WHMCS and WHMCS addons-modules development
-whmcs theme customization
-whmcs payment gateway modules
-whmcs domain registrar
-Whmcs + iphone app development , whmcs + wordpress
** Your Invitation over a private chat would be highly appreciated**
Thanks!!