A list of hand-picked API documentation tools I think worth trying when documenting RESTful endpoints.
Trying is believing, click them all, and bring your own research. :)
I personally like the Swagger most. It’s easy to get, easy to jump start and easy to share, since the documentation is just a file.
And I think a huge number of people also agreed with me, find them at The Open API Initiative.
You may also want to take a look at 3scale if you are looking for a complete package, whose documentation product is built on Swagger.