Its running as mobile app in the browser (on iOS/Android) (not packaged). I assumed this would work on Kindle, too.
I used only one plugin to get system date/time ().
The app is hosted on clay.io but not approved, yet (and costs 0.99$). But I can upload it on my server so you can test it.
Does it have to be in a special (export)format to run on Kindle?
I can send you a private message with the URL and login details.