api.raml

#%RAML 0.8
title: simple API
baseUri: http://localhost:3000

/song:
  get:
    responses:
      200:
        body:
          application/json:
            schema: !include schema.json
            example: |
              {
                "songId": "e29b",
                "songTitle": "The song",
                "albumId": "18310"
              }

fref.json

{
  "type": "string"
}

schema.json

{
  "$schema": "http://json-schema.org/draft-03/schema",

  "type": "object",
  "properties":{
    "songId": {"$ref": "fref.json"}
  },
  "required": ["songId", "albumId", "songTitle"]
}