Great! Do you plan on open-sourcing? Anyway for me to help, even if it's feedback?

Always happy to have feedback! The initial version will be rolled out in the coming weeks. Since it's a major product addition, there'll be some sort of announcement. So either sign up and you'll get a wonderful mass email notification soon. Or circle back in a few weeks.

Some aspects of the site are open sourced:

https://gitlab.com/keithasaurus/simple_html -- basically a port of Elm Html to Python to address what I perceive to be flaws of template rendering.

https://bitbucket.org/cinckitchen/kunits -- just a unit library I wrote. It's central to the site's scaling, etc.

That's a practice that will continue. But the full source will likely not be made public.