Awesome. I really like the design and simplicity. From the example on http://apiary.io/how-it-works how are language bindings generated? How do you know the schema of a message?
I've actually been working on something similar, but more focused on library generation and like a "npm for APIs", e.g. reusable schemas. Instead of markdown I'm using something more akin to Google's Discovery Document (https://developers.google.com/discovery/v1/reference/apis#re...).