What is Ideone?
ideone.com is a... pastebin. But a pastebin like no other on the Internet. More accurate expression would be "online mini IDE and debugging tool".
Ideone is an Italian word for great ideas - because ideone.com is a place where your greatest ideas can spring to life.
Comments and Reviews
Said about Ideone as an alternative
It's simple, straight and clearly structured which is exactly what I need on occasions, while it might not look as good as repl.it also I don't have to sign in as opposed to repl.it, it is once click away online coding environment.
This is most similar to TIO because of the fact that it supports many different languages. Not nearly as many as TIO, but it has most of the major ones. A big (and very welcome) difference is that it also has syntax highlights