I have Swagger API Declaration for services using Swagger v 1.2
My original feeling about Swagger was, that it is very close to JSON Schema (Draft 3 and lately Draft 4)
There is a python tool to do the same by the name openapi2jsonschema. You can simply install it using pip.
pip
The readme for openapi2 shows the simplest way to use it:
openapi2jsonschema https://raw.githubusercontent.com/kubernetes/kubernetes/master/api/openapi-spec/swagger.json
Hope this helps.