Gmail Sending Limits

Question

I'm developing software on a website that uses PHPMailer to send mail through our company's Gmail accounts via SMTP. With the software, a customer signs up for the site and receives a receipt and a video ticket. Two separate emails per customer at sign up. Then, before the event starts we want to resend all the video tickets.

I was wondering what the limits were about sending emails. How many emails can we send per minute, per hour, per day via SMTP using PHPMailer?

Thanks.

UPDATE:

We are using Google Apps for business

Solution 1

Ok, I contacted Google directly to get the answer and here is their reply:

Thank you for your message.

I understand you have a query regarding the Google Apps for Business sending limits. As mentioned in our Help Center article at http://support.google.com/a/bin/answer.py?hl=en&answer=166852, the daily limitation is 2000 messages in a 24-hour period not day. In general, our servers can tolerate one message per second until sending limits are hit. We really don't have an hourly or minute limitation for sending. If you send messages too quickly you may get rate-limited but the account should not lock out.

By rate-limt, since in general one message per second, if you try to send too many messages per second you may get a message telling you that the message cannot be send or you must wait before sending a message.

So after their response we did a test of 1,000 emails. We would send an email out, wait for sent confirmation, wait 2 seconds, and then send the next one. This resulted in successfully sending out all 1,000 emails in about 55 minutes with a gap of 3-4 seconds between each email. Below is the code we used.

<?php

require("PHPMailer/class.phpmailer.php");
$mail = new PHPMailer();
$mail->IsSMTP();

$mail->Host = "smtp.gmail.com";
$mail->SMTPAuth = true;
$mail->Username = 'USERNAME';
$mail->Password = 'PASSWORD';

$mail->From     = "[email protected]";
$mail->FromName = "Gmail Test";

$mail->AddAddress("[email protected]");

for($i=0; $i<=1000; $i++){
    $date = date("H:i:s m/d/Y");
    $mail->Subject  = "$date";

    $mail->Body = "Test $i of PHPMailer.";

    if(!$mail->Send()){
       echo "Error sending: " . $mail->ErrorInfo;
       break;
    }else{
       echo "$i. E-mail sent => $date<BR>";
       sleep(2);
       continue;
    }
}

?>

Solution 2

Gmail

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500 per day 20 emails / hour

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Google Apps

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Messages per day 2000

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Messages auto-forwarded 10,000

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Auto-forward mail filters 20

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Recipients per message 2000(500 external)

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Total recipients per day 10,000

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External recipients per day 3000

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Unique recipients per day 3000(2000 external)

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Recipients per message (sent via SMTP by POP or IMAP users) 99

---

Refer 1

Refer 2

Comments

[Pekka]

Hi, always remember to Google first. A search for Gmail Sending Limits will give you all the resources you need.

[The Duke Of Marshall שלום]

Already did. Didn't find anything. Thanks for the reminder anyways.

[Pekka]

The query gives plenty of good resources though? e.g. support.google.com/mail/answer/22839?hl=en

[Pekka]

and good guidelines here: support.google.com/mail/answer/81126

[The Duke Of Marshall שלום]

Thanks for the link, but that doesn't answer my question. That is back from '08 and doesn't address how many can be sent per minute and/or per hour. This up to date link is from Google themselves and gives me the same problem. support.google.com/a/bin/answer.py?hl=en&answer=166852 Hence my reason for asking elsewhere

[The Duke Of Marshall שלום]

Oops, sorry. Slight problem. We have Google apps for business. Our daily sending limit is 2,000 per day per support.google.com/a/bin/answer.py?hl=en&answer=166852

[Bhavesh G]

What if we use different account for sending mails ?

[The Duke Of Marshall שלום]

If you are using a provider other than Gmail, then you will need to contact your email provider for the limits they have in place for sending emails as well as the SMTP credentials and protocol.

[Bhavesh G]

I mean use different gmail accounts (4-5) for sending mails with php pear.

[The Duke Of Marshall שלום]

I haven't used the PHP Pear avenue for sending emails. Only the PHPMailer. So you'll have to look into the documentation on using that.