const response = await fetch('https://api.emailit.com/v2/emails', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer em_test_51RxCWJ...vS00p61e0qRE',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    from: 'Vaše společnost <hello@vasedomena.cz>',
    to: ['prijemce1@priklad.cz', 'prijemce2@priklad.cz'],
    subject: 'Ahoj světe',
    html: '<h1>Vítejte!</h1><p>Děkujeme za registraci.</p>',
    tracking: {
      loads: true,
      clicks: true
    }
  })
});

const result = await response.json();

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => 'https://api.emailit.com/v2/emails',
  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([
    'from' => 'Vaše společnost <hello@vasedomena.cz>',
    'to' => ['prijemce1@priklad.cz', 'prijemce2@priklad.cz'],
    'subject' => 'Ahoj světe',
    'html' => '<h1>Vítejte!</h1><p>Děkujeme za registraci.</p>',
    'tracking' => [
      'loads' => true,
      'clicks' => true
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    'Authorization: Bearer em_test_51RxCWJ...vS00p61e0qRE',
    'Content-Type: application/json'
  ],
]);

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

curl_close($curl);

if ($err) {
  echo "cURL chyba #:" . $err;
} else {
  $result = json_decode($response, true);
  print_r($result);
}

import requests

response = requests.post(
    'https://api.emailit.com/v2/emails',
    headers={
        'Authorization': 'Bearer em_test_51RxCWJ...vS00p61e0qRE',
        'Content-Type': 'application/json'
    },
    json={
        'from': 'Vaše společnost <hello@vasedomena.cz>',
        'to': ['prijemce1@priklad.cz', 'prijemce2@priklad.cz'],
        'subject': 'Ahoj světe',
        'html': '<h1>Vítejte!</h1><p>Děkujeme za registraci.</p>',
        'tracking': {
            'loads': True,
            'clicks': True
        }
    }
)

result = response.json()
print(result)

require 'net/http'
require 'json'

uri = URI('https://api.emailit.com/v2/emails')
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true

request = Net::HTTP::Post.new(uri)
request['Authorization'] = 'Bearer em_test_51RxCWJ...vS00p61e0qRE'
request['Content-Type'] = 'application/json'
request.body = {
  from: 'Vaše společnost <hello@vasedomena.cz>',
  to: ['prijemce1@priklad.cz', 'prijemce2@priklad.cz'],
  subject: 'Ahoj světe',
  html: '<h1>Vítejte!</h1><p>Děkujeme za registraci.</p>',
  tracking: {
    loads: true,
    clicks: true
  }
}.to_json

response = http.request(request)
result = JSON.parse(response.body)
puts result

package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "net/http"
)

func main() {
    url := "https://api.emailit.com/v2/emails"
    
    data := map[string]interface{}{
        "from": "Vaše společnost <hello@vasedomena.cz>",
        "to": []string{"prijemce1@priklad.cz", "prijemce2@priklad.cz"},
        "subject": "Ahoj světe",
        "html": "<h1>Vítejte!</h1><p>Děkujeme za registraci.</p>",
        "tracking": map[string]bool{
            "loads": true,
            "clicks": true,
        },
    }
    
    jsonData, _ := json.Marshal(data)
    
    req, _ := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
    req.Header.Set("Authorization", "Bearer em_test_51RxCWJ...vS00p61e0qRE")