curl --request POST \
  --url https://test.onlinecheckwriter.com/api/v3/emailchecks \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "emailChecks": [
    {
      "checkId": "RJ6qGAAxJPGE1rD",
      "payeeEmail": "payee@example.com",
      "enableSmsInform": true,
      "payeePhone": "+1234567890",
      "sendAttachment": 1
    },
    {
      "checkId": "dJM5Gbk3LQeY329",
      "payeeEmail": "another@example.com",
      "enableSmsInform": false,
      "sendAttachment": 0
    }
  ]
}
'

import requests

url = "https://test.onlinecheckwriter.com/api/v3/emailchecks"

payload = { "emailChecks": [
        {
            "checkId": "RJ6qGAAxJPGE1rD",
            "payeeEmail": "payee@example.com",
            "enableSmsInform": True,
            "payeePhone": "+1234567890",
            "sendAttachment": 1
        },
        {
            "checkId": "dJM5Gbk3LQeY329",
            "payeeEmail": "another@example.com",
            "enableSmsInform": False,
            "sendAttachment": 0
        }
    ] }
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    emailChecks: [
      {
        checkId: 'RJ6qGAAxJPGE1rD',
        payeeEmail: 'payee@example.com',
        enableSmsInform: true,
        payeePhone: '+1234567890',
        sendAttachment: 1
      },
      {
        checkId: 'dJM5Gbk3LQeY329',
        payeeEmail: 'another@example.com',
        enableSmsInform: false,
        sendAttachment: 0
      }
    ]
  })
};

fetch('https://test.onlinecheckwriter.com/api/v3/emailchecks', 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://test.onlinecheckwriter.com/api/v3/emailchecks",
  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([
    'emailChecks' => [
        [
                'checkId' => 'RJ6qGAAxJPGE1rD',
                'payeeEmail' => 'payee@example.com',
                'enableSmsInform' => true,
                'payeePhone' => '+1234567890',
                'sendAttachment' => 1
        ],
        [
                'checkId' => 'dJM5Gbk3LQeY329',
                'payeeEmail' => 'another@example.com',
                'enableSmsInform' => false,
                'sendAttachment' => 0
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($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://test.onlinecheckwriter.com/api/v3/emailchecks"

	payload := strings.NewReader("{\n  \"emailChecks\": [\n    {\n      \"checkId\": \"RJ6qGAAxJPGE1rD\",\n      \"payeeEmail\": \"payee@example.com\",\n      \"enableSmsInform\": true,\n      \"payeePhone\": \"+1234567890\",\n      \"sendAttachment\": 1\n    },\n    {\n      \"checkId\": \"dJM5Gbk3LQeY329\",\n      \"payeeEmail\": \"another@example.com\",\n      \"enableSmsInform\": false,\n      \"sendAttachment\": 0\n    }\n  ]\n}")

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

	req.Header.Add("Authorization", "Bearer <token>")
	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://test.onlinecheckwriter.com/api/v3/emailchecks")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"emailChecks\": [\n    {\n      \"checkId\": \"RJ6qGAAxJPGE1rD\",\n      \"payeeEmail\": \"payee@example.com\",\n      \"enableSmsInform\": true,\n      \"payeePhone\": \"+1234567890\",\n      \"sendAttachment\": 1\n    },\n    {\n      \"checkId\": \"dJM5Gbk3LQeY329\",\n      \"payeeEmail\": \"another@example.com\",\n      \"enableSmsInform\": false,\n      \"sendAttachment\": 0\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://test.onlinecheckwriter.com/api/v3/emailchecks")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"emailChecks\": [\n    {\n      \"checkId\": \"RJ6qGAAxJPGE1rD\",\n      \"payeeEmail\": \"payee@example.com\",\n      \"enableSmsInform\": true,\n      \"payeePhone\": \"+1234567890\",\n      \"sendAttachment\": 1\n    },\n    {\n      \"checkId\": \"dJM5Gbk3LQeY329\",\n      \"payeeEmail\": \"another@example.com\",\n      \"enableSmsInform\": false,\n      \"sendAttachment\": 0\n    }\n  ]\n}"

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

{
  "success": true,
  "message": "Successfully done"
}

{
  "message": "Unauthenticated."
}

{
  "success": false,
  "errorMsg": "Please verify your Phone Number and Email Address to enable mail Check."
}

{
  "success": false,
  "errorMsg": "The checkId field is required."
}