Why not build this as a middleware layer? You can mount a sinatra app within Rails (/services for instance), and then write your API in a predefined path struc

Why not build this as a middleware layer? You can mount a sinatra app within Rails (/services for instance), and then write your API in a predefined path structure that the gem will look into (within the rails app path maybe?) You can pretty easily share models and whatnot -- and then you have a nice clean place to define/override your DSL. I would have to do some playing to make sure this is valid, but that might be an approach to think about.