Hi and thanks for your feedback :-)
The newspage (https://updates.supanotice.com) will work without JavaScript but the in-app widget that you see in the lower right corner on my page require JavaScript. However, it is completely framework agnostic and is based on web components. It will require that you add a script-tag in head and a tag in the body and you're good to go.
A FAQ for the landing page is on it's way and I will be working on improving the landing page with screenshots and examples so you can get a better feel for it.
I didn't know it worked without JS myself :-) I guess it's a side effect you get when rendering on the server using Elixir / Phoenix