Follow-up: Looks like JSON Schema is emerging as the standard, in part thanks to Swagger and Google adopting it for their APIs. References to Amazon and Heroku doing so as well (not exhaustive list, just what I've found while searching).

Helpful links: https://github.com/swagger-api/swagger-spec/blob/master/vers...

Powerful array of tools to enable wrappers for Go, Scala, Flash, Java, Objc, PHP, Python, Python3, Ruby, Node, and more. https://github.com/swagger-api/swagger-codegen