OkHttpClient client = new OkHttpClient().newBuilder()
  .build();
MediaType mediaType = MediaType.parse("application/json");
RequestBody body = RequestBody.create(mediaType, '{
    "campaign_name": "",
    "campaign_description": "",
    "start_time": "",
    "end_time": "",
    "skill_id": "",
    "opt1": "",
    "opt2": "",
    "opt3": "",
    "opt4": "",
    "opt5": "",
    "opt6": "",
    "opt7": "",
    "opt8": "",
    "opt9": "",
    "opt10": "",
    "opt11": "",
    "opt12": "",
    "enable_edition": ""
}');
Request request = new Request.Builder()
  .url("https://wv{{wolkvox_server}}.wolkvox.com/api/v2/campaign.php?api=create_campaign&type_campaign={{type_campaign}}")
  .method("POST", body)
  .addHeader("wolkvox-token", "{{token}}")
  .addHeader("Content-Type", "application/json")
  .build();
Response response = client.newCall(request).execute();