How do you document a REST API?

Question

How do you document a REST API? Not just the documentation of what the resources are, but really what is the data that gets sent in the request and what the data is that gets sent back in the response. It is not useful enough to know that something expects XML to be sent and returns XML; or JASN; or whatever. How do you document the data that gets sent in the request and the data sent back in the response?

Best I could find so far is the Enunciate tool where you can document your REST API and the data elements. Is Enunciate the right type of tool for this and am I missing out on any other tools that offer this that I should look at?

Consumers of my REST API can be in any language python, Java, .NET, etc

Answer 1

I've experience using Enunciate which is great but I don't really like the clients that you can generate with it. On the other hand, I've been using swagger on my last projects and it seems to fit my needs, it's really cool you should give a try!

UPDATE 03/08/2016: Looks like you can use Enunciate to build swagger docs.
See this.