I use prism (stoplight/prism-cli v5.12.0) to serve OpenApi v3.0 yaml file.

Here is structure for range from 10 to 20:

type: object
properties:
  total:
    type: 'integer'
    example: 100
    x-faker:
      datatype.number: // random.number is depricated
        min: 10
        max: 20