Mails sent using PHP taking too much time

Question

I have written a class in PHP which I use for sending mails making use of a Gmail account. This class in turn uses the PHPMailer library. The setup is WAMP 2.4 on Windows Vista. Using the microtime() function in PHP, I see that it takes anywhere between 5 to 6 seconds to send a single mail. Is it normal for a PHP script running on the kind of set up that I have to take as much as 5-6 seconds for a single mail going out. Here is code for the class.

<?php

require_once("phpmailer/class.phpmailer.php");
require_once("phpmailer/class.smtp.php");

class Mailer {

    // Needs to be set per object
    public $subject;
    public $message;
    public $to_name;
    public $to;

    private $mail; // This is the main mail object that'll be initialized 

    public function __construct() {

        // Need to create a PHPMailer object in the constuctor and return it for use in this class. 

        $mail = new PHPMailer();

        $from_name = "bleh";
        $from = "bleh@gmail.com";
        $username = "bleh";
        $password = "bleh";

        $mail->FromName = $from_name;
        $mail->From = $from;
        $mail->Username = $username;
        $mail->Password = $password;

        $mail->IsSMTP();
        $mail->Host = "smtp.gmail.com";
        // $mail->Port = 587; // Turns out, I dont need this one. 
        $mail->SMTPAuth = true; // gmail requires this
        $mail->SMTPSecure = 'tls'; // gmail requires this

        $this->mail = $mail;


    }


    function send() {

        $mail = $this->mail; // The mail object 

        $mail->Subject = $this->subject;
        $mail->Body = $this->message;
        $mail->AddAddress($this->to, $this->to_name);

        $result = $mail->Send();
        return $result;

    }
}
?>

Code used to test this -

$startTime = microtime(true);
require_once("mailer.php");

$mailer = new Mailer();

$mailer->subject = "Test";
$mailer->message = "Test";
$mailer->to_name = "My Name";
$mailer->to = "anemail@address";

$mailer->send();
echo "Time:  " . number_format(( microtime(true) - $startTime), 4) . " Seconds\n";

It is not normal for any SMTP conversation to take 5-6 seconds. If it did, we would have FAR less spam :-) It is conceivable that Gmail is rate limiting you, if they consider your sending activity suspect. Not sure if they DO that, but they could. — Eric J., Apr 13 '14 at 19:13
Ok. I have shared my code now for anyone to tell me if my code is slowing it down. — user1720897, Apr 13 '14 at 19:16
I don't see anything in your PHP code that should cause the SMTP conversation to take nearly that long. Where does your timing of 5-6 seconds start and end? — Eric J., Apr 13 '14 at 19:20
How long does it take if you just use the simple `mail()` from PHP? I know it isn't what you try to reach. But would that work normal? — JochemQuery, Apr 13 '14 at 19:32
I cant use the mail() function in my set up as it would attempt to use a binary like sendmail to send the actual mail. And I do not have sendmail in my setup. — user1720897, Apr 13 '14 at 19:34

score 7 · Accepted Answer · edited Oct 07 '21 at 05:51

It is very common for SMTP to take a long time - it's even used as an anti-spam measure in the form of greetdelay/tarpit mechanisms. RFC2821 section 4.5.3.2 allows up to a 5 minute delay before traffic starts. SMTP is not intended for interactive use (since it can't queue in that situation), and sending via SMTP during web page submission can suffer because of that. Sendmail or SMTP via an async process would avoid the issue.

In PHPMailer you can enable SMTP debug output and it will show you what's happening so you'll be able to see what's taking the time:

$mail->SMTPDebug = 2;

score 1 · Answer 2 · edited May 23 '17 at 12:07

As mentioned in my comment, Gmail may be rate limiting you. There could also be some aspect of your network communication with Gmail that is causing the issue.

You can manually begin an SMTP conversation with Gmail from the command line. Watch for how long each step takes, and check for any codes / messages that may come back from Gmail indicating a problem.

For details on how to create a manual SMTP conversation see

Connecting to smtp.gmail.com via command line

Messages that come back will be Base64 encoded as indicated in that answer. You can use an online Base64 decoder to convert back to plain text.

Note: The link shows instructions for Linux. If you don't have a Linux server to test from, you can use Cygwin (for windows) or an OpenSSH for Windows package that does not require a full Cygwin install

Ok. I will compare the times with a manual SMTP conversation. — user1720897, Apr 13 '14 at 19:32

score 0 · Answer 3 · answered May 05 '20 at 08:54

I have faced to same problem and its getting around 30s to send the email.

The problem was system running PHP server got hang until the email is sent.

I tried many solutions but easiest way was start another PHP server locally on different port for handle the mail sending.

The main PHP server (system running server) will handed over the mail sending request to the mail PHP server and continue no the process.

Still 30s will take to send the email, but not effect to the main PHP server.

Mails sent using PHP taking too much time

3 Answers3