Subdomain submition protection help

i have a subdomain if some one open it will post some data using php curl.
i have done header protection and auth with rest api.

now how can i protect the subdomain to auto hit or false or boot protection.here is the url to check https://1bang1.onlinebzsolutions.com/

i want a user can access this url every 30 min after, after 1 time access this url.

session_start();
$dns = $_SERVER['SERVER_NAME'];
$host = explode('.', $dns);
$subdomain = $host[0];
$domain = $host[1].'.'.$host[2];
	
$serverdetails = $_SERVER['HTTP_USER_AGENT'];
$ip=$_SERVER['REMOTE_ADDR'];
$token= session_id();;
$poston= date("Y-m-d H:i:s");



$sUrl="myurl";

$data=array('domain' => $domain,'subdomain' => $subdomain,'serverdetails' => $serverdetails,'ip' => $ip,'token' => $token,'poston' => $poston);
	
$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => $sUrl,
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => '',
  CURLOPT_MAXREDIRS => 1,
  CURLOPT_TIMEOUT => 0,
  CURLOPT_FOLLOWLOCATION => true,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => 'POST',
  CURLOPT_POSTFIELDS=> $data,
  CURLOPT_HTTPHEADER => array(
    'header-token: mytoken',
    'Authorization: Basic myoth',
  ),
));

$response = curl_exec($curl);

curl_close($curl);
echo $response;