ejemplo.php

<?php
$postBody = file_get_contents('php://input');

$message = json_decode($postBody, true);
if ($message) {
  $type = $message['Type'];
  if (strcmp($type, 'SubscriptionConfirmation') == 0) {
    file_get_contents($message['SubscribeURL']);
  } elseif (strcmp($type, 'Notification') == 0) {
    $subject = $message['Subject'];
    if (strcmp($subject, 'New Study') == 0) {
      echo $message['Message'];
      // ...
    } elseif (strcmp($subject, 'New Interpretation') == 0) {
      echo $message['Message'];
      // ...
    } else {
      http_response_code(400);
    }
  } else {
    http_response_code(400);
  }
} else {
  http_response_code(400);
}
?>