curl --request POST \
  --url https://{appId}.api-{region}.cometchat.io/v3/campaigns/notifications/messages \
  --header 'Content-Type: application/json' \
  --header 'apikey: <api-key>' \
  --header 'appid: <appid>' \
  --data '
{
  "templateId": "order_update",
  "receivers": [
    "<string>"
  ],
  "variables": {
    "user_42": {
      "user_name": "John",
      "order_id": "12345"
    },
    "user_43": {
      "user_name": "Sarah",
      "order_id": "12346"
    }
  },
  "tag": "<string>"
}
'

import requests

url = "https://{appId}.api-{region}.cometchat.io/v3/campaigns/notifications/messages"

payload = {
    "templateId": "order_update",
    "receivers": ["<string>"],
    "variables": {
        "user_42": {
            "user_name": "John",
            "order_id": "12345"
        },
        "user_43": {
            "user_name": "Sarah",
            "order_id": "12346"
        }
    },
    "tag": "<string>"
}
headers = {
    "appid": "<appid>",
    "apikey": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {appid: '<appid>', apikey: '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    templateId: 'order_update',
    receivers: ['<string>'],
    variables: {
      user_42: {user_name: 'John', order_id: '12345'},
      user_43: {user_name: 'Sarah', order_id: '12346'}
    },
    tag: '<string>'
  })
};

fetch('https://{appId}.api-{region}.cometchat.io/v3/campaigns/notifications/messages', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://{appId}.api-{region}.cometchat.io/v3/campaigns/notifications/messages",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'templateId' => 'order_update',
    'receivers' => [
        '<string>'
    ],
    'variables' => [
        'user_42' => [
                'user_name' => 'John',
                'order_id' => '12345'
        ],
        'user_43' => [
                'user_name' => 'Sarah',
                'order_id' => '12346'
        ]
    ],
    'tag' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "apikey: <api-key>",
    "appid: <appid>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

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

func main() {

	url := "https://{appId}.api-{region}.cometchat.io/v3/campaigns/notifications/messages"

	payload := strings.NewReader("{\n  \"templateId\": \"order_update\",\n  \"receivers\": [\n    \"<string>\"\n  ],\n  \"variables\": {\n    \"user_42\": {\n      \"user_name\": \"John\",\n      \"order_id\": \"12345\"\n    },\n    \"user_43\": {\n      \"user_name\": \"Sarah\",\n      \"order_id\": \"12346\"\n    }\n  },\n  \"tag\": \"<string>\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("appid", "<appid>")
	req.Header.Add("apikey", "<api-key>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://{appId}.api-{region}.cometchat.io/v3/campaigns/notifications/messages")
  .header("appid", "<appid>")
  .header("apikey", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"templateId\": \"order_update\",\n  \"receivers\": [\n    \"<string>\"\n  ],\n  \"variables\": {\n    \"user_42\": {\n      \"user_name\": \"John\",\n      \"order_id\": \"12345\"\n    },\n    \"user_43\": {\n      \"user_name\": \"Sarah\",\n      \"order_id\": \"12346\"\n    }\n  },\n  \"tag\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://{appId}.api-{region}.cometchat.io/v3/campaigns/notifications/messages")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["appid"] = '<appid>'
request["apikey"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"templateId\": \"order_update\",\n  \"receivers\": [\n    \"<string>\"\n  ],\n  \"variables\": {\n    \"user_42\": {\n      \"user_name\": \"John\",\n      \"order_id\": \"12345\"\n    },\n    \"user_43\": {\n      \"user_name\": \"Sarah\",\n      \"order_id\": \"12346\"\n    }\n  },\n  \"tag\": \"<string>\"\n}"

response = http.request(request)
puts response.read_body