This is a great way of putting a UI on top of JSON! I created http://jsonblob.com/ to accomplish the same thing, but a spreadsheet is much more familiar than a JSON editor.
Cool site. What's the development status? Seems well-polished in some regards but pretty broken in others (I can't get open/save/clear to work at all). [Edit: i'm using chrome latest release]
It was something that I built a while back, mostly over a weekend, but haven't really touched since. It's running on a free Heroku dyno and coming close to the 512M limit (grails is quite the memory hog), so I've been rewriting it using DropWizard so that it can take better advantage of the dyno.
It does seem pretty broken with the latest Chrome (seems like menu items now require a double click?), so I'll take a look and try to get it fixed soonish.
