function testPOST() {

  var url = "https://europe-west1-process-simplifier.cloudfunctions.net/email-sender"

  var payload =
      {
          "sferien":
              {
                  "name": "BALON",
                  "surname": "ANTOINE"
              },
          "status": "BAD",
          "error": "TOO_MANY_DAYS"
      };

  var options =
      {
        "method"  : "POST",
        "payload" : payload,
        "followRedirects" : true,
        "muteHttpExceptions": true
      };

  var result = UrlFetchApp.fetch(url, options);

  if (result.getResponseCode() == 200) {

    var params = JSON.parse(result.getContentText());

    Logger.log(params.name);
  }

}