UPD: changed to base64 mime type

php/mailapi.php

@@ -0,0 +1,28 @@
+<?php
+
+if (empty($_POST)) {
+	echo 'Usage: curl -d "subject=email subject&sender=SENDER@DOMAIN.TLD&recipient=RECIPIENT@DOMAIN.TLD&message=$(base64 /tmp/mailbody.txt)" -X POST https://racker.pro/mailapi/';
+	exit();
+} else {
+
+include('Mail.php');
+
+$to = $_POST['recipient'];
+$subject = $_POST['subject'];
+$message = $_POST['message'];
+$headers[] = 'MIME-Version: 1.0';
+$headers[] = 'Content-type: text/plain; charset=ISO-8859-1';
+$headers[] = 'Content-Transfer-Encoding: base64';
+$headers[] = 'X-Mailer: PHP/' . phpversion();
+//$headers[] = 'To: ' . $_POST['recipient'];
+$headers[] = 'From: ' . $_POST['sender'];
+
+if (mail($to, $subject, $message, implode("\r\n", $headers))) {
+  echo 'Your message has been sent.';
+} else {
+  echo 'There was a problem sending the email.';
+}
+}
+
+?>
+