How to rate limit emails sent in phpList

In our previous article, we installed phpList. Before we continue with creating a mailing list that users can subscribe to, there are some default settings that we must change within the phpList configuration.

By default, phpList will attempt to send out as many emails as fast as possible. To prevent possible issues with spam, accounts on our shared servers have a limit set to the maximum number of emails that can be sent per hour. That limit is set to 250 per domain per hour. What this means is that if you have 700 people in your mailing list and you try to send all of the emails at once with phpList, 250 emails will be sent and the other 450 will fail. To resolve this issue, we need to tell phpList to only send 250 emails per hour.

Please note that we do on a case by case basis increase this number for our users. If you’re interested in being able to send more than 250 emails per hour per domain, please see our Bulk Mailing Request article.

Please also keep in mind that if you normally send 10 emails per hour during your daily routine, then you may need to set phpList to only send 240 emails per hour. In the example below, we will walk you through the steps to configure phpList to send 204 emails per hour at a rate of 17 emails every 5 minutes.

How to edit batch settings in phpList

1. Log into your cPanel
2. Access your File Manager by clicking the “File Manager” icon.
3. Navigate to the directory you installed phplist into. Then navigate to the config directory within that. From there, right click on config.php and click edit. If you’re prompted with a “Text-Editor” window, ensure “utf-8” is selected in the drop down and then click “Edit”
4. You are now looking at the phpList configuration file. There is quite a bit of content in this file, your focus is on finding these two lines:

   define("MAILQUEUE_BATCH_SIZE",0);
   define("MAILQUEUE_BATCH_PERIOD",100);
   Change these values to what we have below:
   define("MAILQUEUE_BATCH_SIZE",17);
   define("MAILQUEUE_BATCH_PERIOD",300);
   

   The changes that we made told phpList to send 17 emails every 300 seconds (5 minutes).

5. Click “Save Changes”.

Please be aware that you will see the above lines several places in the config file. Please be sure to edit the lines that do not start with a pound sign. There is only one line for each setting that does not begin with #.  In the example below, the green lines are where we made the edit, and the red lines are where we DID NOT make any edits due to the line starting with #.

How does rate limiting work in phpList?

Later in our tutorial series, we’ll show you how to send a message to a mailing list in phpList. Because we’re talking about rate limiting right now, we’d like to give you a sneak peak at what it will look like when you send to 400+ users with the above options set.

We initiall sent a message to our list at 9:20 am. The confirmation message below mentions that phpList sent 17 emails, and then will wait 300 seconds (5 minutes) before sending more.

After 5 minutes (it is now 9:25 am), your browser will reload, and you will see another message similar to the below. This message states that in the last run 17 messages were sent, and another 17 messages have been sent now:

At this point, you simply need to leave your browser open. Every 5 minutes, your browser will reload and another 17 emails will be sent.

What happens if my browser closes during sending of my messages?

We had the same question. Right now we’re in the middle of sending 400+ emails at a rate of 17 emails every 5 minutes. We’ve already sent about 51 emails, and we just closed our browser. With the browser closed, phpList will not be able to process the rest of the messages we need sent.

To continue sending your list, simply log back into you phpList admin and click the “process queue” link in the right sidebar: