[php] How to send 100,000 emails weekly?

How can one send an email to 100,000 users on a weekly basis in PHP? This includes mail to subscribers using the following providers:

• AOL
• G-Mail
• Hotmail
• Yahoo

It is important that all e-mail actually be delivered, to the extent that it is possible. Obviously, just sending the mail conventionally would do nothing but create problems.

Is there a library for PHP that makes this simpler?

People have recommended MailChimp which is a good vendor for bulk email. If you're looking for a good vendor for transactional email, I might be able to help.

Over the past 6 months, we used four different SMTP vendors with the goal of figuring out which was the best one.

Here's a summary of what we found...

AuthSMTP

• Cheapest around
• No analysis/reporting
• No tracking for opens/clicks
• Had slight hesitation on some sends

Postmark

• Very cheap, but not as cheap as AuthSMTP
• Beautiful cpanel but no tracking on opens/clicks
• Send-level activity tracking so you can open a single email that was sent and look at how it looked and the delivery data.
• Have to use API. Sending by SMTP was recently introduced but it's buggy. For instance, we noticed that quotes (") in the subject line are stripped.
• Cannot send any attachment you want. Must be on approved list of file types and under a certain size. (10 MB I think)
• Requires a set list of from names/addresses.

JangoSMTP

• Expensive in relation to the others – more than 10 times in some cases
• Ugly cpanel but great tracking on opens/clicks with email-level detail
• Had hesitation, at times, when sending. On two occasions, sends took an hour to be delivered
• Requires a set list of from name/addresses.

SendGrid

• Not quite a cheap as AuthSMTP but still very cheap. Many customers can exist on 200 free sends per day.
• Decent cpanel but no in-depth detail on open/click tracking
• Lots of API options. Options (open/click tracking, etc) can be custom defined on an email-by-email basis. Inbound (reply) email can be posted to our HTTP end point.
• Absolutely zero hesitation on sends. Every email sent landed in the inbox almost immediately.
• Can send from any from name/address.

Conclusion

SendGrid was the best with Postmark coming in second place. We never saw any hesitation in send times with either of those two - in some cases we sent several hundred emails at once - and they both have the best ROI, given a solid featureset.

Here is what I did recently in PHP on one of my bigger systems:

1. User inputs newsletter text and selects the recipients (which generates a query to retrieve the email addresses for later).

2. Add the newsletter text and recipients query to a row in mysql table called *email_queue*

   • (The table email_queue has the columns "to" "subject" "body" "priority")

3. I created another script, which runs every minute as a cron job. It uses the SwiftMailer class. This script simply:

   • during business hours, sends all email with priority == 0

   • after hours, send other emails by priority

Depending on the hosts settings, I can now have it throttle using standard swiftmailers plugins like antiflood and throttle...

$mailer->registerPlugin(new Swift_Plugins_AntiFloodPlugin(50, 30));

and

$mailer->registerPlugin(new Swift_Plugins_ThrottlerPlugin( 100, Swift_Plugins_ThrottlerPlugin::MESSAGES_PER_MINUTE ));

etc, etc..

I have expanded it way beyond this pseudocode, with attachments, and many other configurable settings, but it works very well as long as your server is setup correctly to send email. (Probably wont work on shared hosting, but in theory it should...) Swiftmailer even has a setting

$message->setReturnPath

Which I now use to track bounces...

Happy Trails! (Happy Emails?)