Ask HN: API devs, what do you use for API documentation?

I build mine on top of Grape[0] and use Swagger[1] to do a lot of the heavy lifting (also provides a web-based console); I can convert the generated Swagger docs to markdown too.

[0] https://github.com/intridea/grape [1] https://github.com/tim-vandecasteele/grape-swagger

I use ASP.NET Web API 2 which has an awesome built-in documentation generator:

http://www.asp.net/web-api/overview/creating-web-apis/creati...

http://weblogs.asp.net/jongalloway//looking-at-asp-net-mvc-5...

Thanks to this I have an up-to-date documentation ready at every build. It comes with nice sample data in both XML and JSON, descriptions of all the parameters/output including constraints, etc.

Also check out http://apiblueprint.org/ which seems to be by the folks at Apiary.io

... and this blog post all about API documentation: http://codebetter.com/glennblock/2014/02/06/a-discussion-on-...

I use Apiary. Very happy with them.