Sendgrid is a relatively new cloud-based service that takes care of mailing list SMTP delivery and attempts to get the highest possible deliverability rate. We didn't want to have to manage our own SMTP server here at the Participatory Politics Foundation, so when we migrated to CiviCRM recently, we decided to take the sendgrid route for SMTP.

Integration with CiviMail is pretty straightforward: all you really have to do is change your SMTP settings in CIviMail to match your sengrid credentials. But sendgrid is different from a typical SMTP server in the way it handles bounces and spam reports. First of all, sendgrid uses a reputation score to keep spammers away -- the gist of it is that 80% or more of your messages must deliver without failures. If you go below 80%, your sendgrid account can be suspended. Furthermore, they don't send any bounce or spam report messages back to you, the sender. And they don't attempt redelivery. Instead, they record the e-mail addresses that bounced and prevent further messages to those addresses from being delivered -- so your score will never drop if you try to send further messages to bounced addresses.

So, we could actually stop once we change the SMTP settings, but then we'd keep trying to mail to all of those bounced addresses, and that's kind of annoying even if it doesn't impact our sendgrid reputation. It would be better to keep the bounce and spam report lists on sendgrid in sync with CiviCRM, and mark CiviCRM contacts as "on hold" when they bounce. Sendgrid has a simple Event API that will push notifications of bounces and spam reports to a URL on your server.

We wrote a PHP endpoint to handle these events. You can grab our code here. You will want to change the civicrm path and unique key, which you'll provide to sendgrid in your post notification URL.

Make this script publicly accessible and test it out like this:


$ wget -O - -S --post-data 'email=bouncing-contact@hotmail.com&event=bounce' 'http://yoursite.org/sendgrid-notifier.php?key=CHANGE_THIS_TO_YOUR_UNIQUE_KEY_FROM_ABOVE'


Once it's working to your satisfaction, you can point sendgrid to your URL, and away you go!

Some changes we'd love to see in the future:

• Turn this into an official module/plug-in?
• Sendgrid also sends a bounce reason message and a bounce status code in the push notification -- it would be nice to record these somehow.
• ... and, for some temporary failures, we could tell sendgrid to remove the address from their bounce list, via their web api.

I welcome your feedback and suggestions for other improvements.

PS. The sendgrid Event API also notifies you of opens, clicks, and unsubscribes, but we turned all of those off in our sendgrid filter settings, since CiviMail already provides all of these for us.