Send email with mailgun.

send_email.php

<?php
  //from email can be set in the relevant curl_setopt below.
  //for my purposes, I was always using the same from email and didn't need one more variable to pass into this function.
  //

  function send_mail($email,$subject,$msg,$mailDomain,$api) {
   $curl = curl_init();
   curl_setopt($curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
   curl_setopt($curl, CURLOPT_USERPWD, 'api:'.$api_key);
   curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
   curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'POST');
   curl_setopt($curl, CURLOPT_URL, 'https://api.mailgun.net/v2/'.$mailDomain.'/messages');
   curl_setopt($curl, CURLOPT_POSTFIELDS, array(
    'from' => "no-reply <no-reply@$mailDomain>",
    'to' => $email,
    'subject' => $subject,
    'html' => $msg
   ));
   $result = curl_exec($ch);
   curl_close($ch);
   return $result;
  }


  //uncomment (and complete) the lines below to test the above function with your settings.

  //$email="user@example.com";
  //$subject="Test of email configuration.";
  //$msg="This message should be considered a success";
  //$mailDomain="example.com"
  //$mailgunAPI="ENTER YOUR API KEY HERE"

  //$result = send_mail($email,$subject,$msg,$mailDomain,$mailgunAPI);

  //echo $result;

?>