{
  "bulkId": "BULK-ID-123-xyz",
  "messages": [
    {
      "callbackData": "DLR callback data",
      "destinations": [
        {
          "messageId": "MESSAGE-ID-123-xyz",
          "to": "41793026727"
        },
        {
          "to": "41793026834"
        }
      ],
      "flash": false,
      "from": "SMSC",
      "intermediateReport": true,
      "language": {
        "languageCode": "TR"
      },
      "notifyContentType": "application/json",
      "notifyUrl": "https://www.example.com/sms/advanced",
      "text": "Artık Ulusal Dil Tanımlayıcısı ile Türkçe karakterli smslerinizi rahatlıkla iletebilirsiniz.",
      "transliteration": "TURKISH",
      "validityPeriod": 720
    },
    {
      "deliveryTimeWindow": {
        "days": [
          "MONDAY",
          "TUESDAY",
          "WEDNESDAY",
          "THURSDAY",
          "FRIDAY",
          "SATURDAY",
          "SUNDAY"
        ],
        "from": {
          "hour": 6,
          "minute": 0
        },
        "to": {
          "hour": 15,
          "minute": 30
        }
      },
      "destinations": [
        {
          "to": "41793026700"
        }
      ],
      "from": "41793026700",
      "sendAt": "2021-08-25T16:00:00.000+0000",
      "text": "A long time ago, in a galaxy far, far away... It is a period of civil war. Rebel spaceships, striking from a hidden base, have won their first victory against the evil Galactic Empire."
    }
  ],
  "tracking": {
    "track": "SMS",
    "type": "MY_CAMPAIGN"
  }
}
        

            package main

import (
    "fmt"
    "strings"
    "net/http"
    "io/ioutil"
)

func main() {

    url := "https://example.com/sms/1/text/advanced"
    method := "POST"

    payload := strings.NewReader(`{"bulkId":"BULK-ID-123-xyz","messages":[{"callbackData":"DLR callback data","destinations":[{"messageId":"MESSAGE-ID-123-xyz","to":"41793026727"},{"to":"41793026834"}],"flash":false,"from":"SMSC","intermediateReport":true,"language":{"languageCode":"TR"},"notifyContentType":"application/json","notifyUrl":"https://www.example.com/sms/advanced","text":"Artık Ulusal Dil Tanımlayıcısı ile Türkçe karakterli smslerinizi rahatlıkla iletebilirsiniz.","transliteration":"TURKISH","validityPeriod":720},{"deliveryTimeWindow":{"days":["MONDAY","TUESDAY","WEDNESDAY","THURSDAY","FRIDAY","SATURDAY","SUNDAY"],"from":{"hour":6,"minute":0},"to":{"hour":15,"minute":30}},"destinations":[{"to":"41793026700"}],"from":"41793026700","sendAt":"2021-08-25T16:00:00.000+0000","text":"A long time ago, in a galaxy far, far away... It is a period of civil war. Rebel spaceships, striking from a hidden base, have won their first victory against the evil Galactic Empire."}],"tracking":{"track":"SMS","type":"MY_CAMPAIGN"}}`)

    client := &http.Client {
    }
    req, err := http.NewRequest(method, url, payload)

    if err != nil {
        fmt.Println(err)
        return
    }
    req.Header.Add("Authorization", "{authorization}")
    req.Header.Add("Content-Type", "application/json")
    req.Header.Add("Accept", "application/json")

    res, err := client.Do(req)
    if err != nil {
        fmt.Println(err)
        return
    }
    defer res.Body.Close()

    body, err := ioutil.ReadAll(res.Body)
    if err != nil {
        fmt.Println(err)
        return
    }
    fmt.Println(string(body))
}