PHPLIST limitations to database size and sending capacity


I am wondering if phpList has any limitations to its database size and capacity to handle very large mailings. In brief we have obtained our own multi-threaded mailing relay capable of handling over 1 million emails a day through the use of multiple IP based virtual smtp servers. This is a very capable and scalable solution. However our front-end mailing software is just not capable of keeping up with our demands. It is quite simply very poorly coded and becomes increasingly slower with every batch of emails it sends.

Is PHPLIST capable of handling 40k to 50k emails per hour provided the relay channels are there to achieve it?

Is PHPlLIST also capable of handling contact lists in the millions without suffering any serious performance hit?

Any information on PHPLIST’s known limitations would be very helpful. I do understand that hardware will play a critical role in this so let us assume a dedicated 8 core, 64-bit server with 32 gigs of ram with raid 10 sas drives as a reference point. All server resources are for phplist and mysql/apache to run it.


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Hi, best contact for this I think. The core developers offer consulting work.


Using a standard install, with no optimization, it most likely won’t go that fast.
Overall sending speed depends on many things, some of which are not related to phpList.
The overall system speed is a function of all of the parts, and how they interact together.
You would most likely need to have a tuned configuration of the environment that phpList operates in.
If you need details on how to do this, I can provide some input (as a consultant, for a fee)…

It depends on all kinds of stuff and it is not necessarily phpList that may cause a low speed. For example the speed of DNS makes a big difference. I’ve heard people doubling their phpList sending speed by increasing the TTL on their DNS server. I make speeds of 35k and up, just on my local laptop, running the web, database and mailserver all in the same machine. The mail relay even in an VM running in VirtualBox. And that’s with campaigns containing complex layouts and several inline images. So, if you want speed, you want to have a good system administrator to tweak the externals. But sure, no doubt phpList can be optimised in certain places as well.

Thanks for the input everyone. Only one way to really find out and that is setup a real working environment and put it through its motions. Here is what I am planning: use a list of about 200K to 300K; setup PHPList with no delays, ie going full throttle.

Michiel; you mentioned DNS being a potential issue but this is assuming PHPList is sending the emails itself via a local socket, correct? In my case it will be handing off the emails to an SMTP relay which will perform the MX lookups so this should not be a concern for us.