how to define a model for following json data

I want to define a rest api to post below json data to ,how can I define a model?

[
  {
    "labels": {
      "<labelname>": "<labelvalue>",
      ...
    },
    "annotations": {
      "<labelname>": "<labelvalue>",
    },
    "startsAt": "<rfc3339>",
    "endsAt": "<rfc3339>"
    "generatorURL": "<generator_url>"
  },
  ...
]

thanks