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/creating-api-help-pages ht

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/creating-api-help-pages http://www.asp.net/web-api/overview/creating-web-apis/creati... http://weblogs.asp.net/jongalloway//looking-at-asp-net-mvc-5-1-and-web-api-2-1-part-4-web-api-help-pages-bson-and-global-error-handling 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.