One question regarding the states: when do I get a new State allocated? Is it with every new tab? It's definitely not per-browser-session: if I open a new tab I seem to get a new state, while undoing a closed tab seems to recover its state with it though.
Also are old states gc'ed?
I am not very familiar with how modern Python wsgi servers manage states, but in Java e.g. states can be cached in the heap of the one and same JVM --- can one say that the need to use an external state store like Redis is a direct result of the underlying web server having to launch multiple Python processes in order to scale up for greater loads?
(Pretty cool, btw! Congrats on the launch)