The place for music theory specific questions, comments, and discussions.
Can you use Hooktheory on your iPad and iPhone?
It will work in a pinch (the new version of Hookpad was built using technologies that are compatible with Mobile devices like iPad and iPhone), however the UI was not designed with mobile in mind. I suspect it would be very frustrating if you tried to do serious composing on an iPad other than viewing and a quick edit here or there. I certainly wouldn’t recommend using it as your primary platform for now. We eventually do want to make a mobile friendly UI though