With the source code open it wouldn't be too hard to exploit this to do just about anything. Sure you could the same with a free Heroku instance but this lets you do it anonomously. Not that I would do such things but when I see these kinds of apps I wonder how they could be made more secure.
Code School open sourced their ruby sandboxing. Might be worth a look. https://github.com/envylabs/RubyCop
Re: Ruby Fiddle: Ruby Snippets in the Browser
#21Oh man, awesome. thanks.