I uploaded a test app to Ionic (don't know the exact name for this) with the command ionic upload from the command line, and I can access them nicely with the Ionic View application I have installed on my iPhone.
However, I remember that they have a web interface for this too, but can't find the link for the life of me. I searched the website, went through my emails, googled, but nothing. I even found the same question on the official forum - sadly unanswered.
And, sure enough, after going through my deleted emails I found a welcome email from Ionic stating that the login is at https://apps.ionic.io/login. Will reply to that official post too...