API contains info about the API.

Body describes a response body.

Parameter describes an input parameter, which could be in the URL path, in the query string, or in the request body.

Path describes a path served by the API.

Responses describes the possible responses.

RoundTrip describes an HTTP round trip with a given method and path.

Schema is the schema of a specific parameter or or the schema used by the response body.

Swagger is the toplevel structure.