Oh damn, that's fantastic! I wanted to write a small server that did something between this and Fire above (i.e. allowed you to drop a Python script into a directory and would create a UI for its functions). It's a great way to make small, random functions I've written accessible to people with zero work.

Just found out about this, looks cool! Unfortunately file handling is a bit wonky, I suspect some of that is just the web platform (e.g. can't select directories), while some of it is probably due to a lack of bandwidth from what looks to mostly be a solo developer.