You must not do this!
As a Zapable member you have access to all your apps and the potential to create more apps through the Zapable interface but you don't want to share that interface with anyone.
Not only is it a very powerful tool (that isn't free) but if you are selling to clients you don't want to reveal just how easy it is to create apps with Zapable - they may complain about the deal you struck!
You would be doing yourself a disservice.
Furthermore, you can (your choice) charge a recurring fee to clients so that they can gain access to the white label push notifications area.
It's win-win. They get to send push notifications simply without worrying about app development or maintenance, and you get a recurring fee.