Measuring email marketing deliverability

Email marketing vendors often boast that their infrastructure and ISP relations teams lead to high deliverability. While it is true that any ESP is likely to significantly beat a company’s in-house solution, it becomes more difficult when trying to compare one ESP’s deliverability to another.


When you are evaluating email vendors, I highly recommend starting by subscribing to their respective newsletters via multiple email addresses (Gmail, Yahoo!, corporate account, etc.). Then tote whether or not the messages are delivered to your inbox in major email clients. This would seem to be an obvious test but many buyers simply rely on reputation rather than experimentation when making a decision.

Measuring the Sender Score of the Vendors

Return Path, who operates the largest email accreditation service, Sender Score Certified, rates IP addresses by giving them sender scores. The score is made up of several different factors such as SPAM complaints, sending volume, amount of mail sent to unknown addresses. and the IP’s DNS settings. Anything lower than 70 should be avoided. Ideally you want to see something that is 80 or higher.

To find the IP address of the mail server for an email you receive, you will need to see the message’s original headers.

In Gmail for example, click on the downward arrow on the top right of an email. Then select “Show Original” to see the message’s headers. You can then see the IP address of the sender and check it here. You will be surprised by how many low scores you will find. You can do this in a similar manner with Yahoo! Mail and other major email clients.

Checking Email Authentication

The header also gives you other useful information such as whether or not the emails pass various types of authentication. ISPs and corporate filters use some or all of the four major authentication frameworks to help classify email. Most email clients will allow you to check your incoming emails to see if they are authenticated. Gmail for example will tell you whether or not the email passes SPF and DKIM authentication. Simply do a find for “DKIM” when viewing the header. The more levels of authentication your ESP uses, the better the deliverability is likely to be.

There is of course a lot more than deliverability that goes into an email service provider evaluation (feature set, ease of use, services component, etc.) but this should at least give buyers an objective to way measure one of the more esoteric aspects of email marketing.

About Adam Blitzer
Adam Blitzer is the Vice President of Marketing at Pardot and has been in the interactive marketing world for the better part of a decade.

Leave a Reply

Gravatar Logo

Please log in to to post a comment to your blog.

Twitter picture

You are commenting using your Twitter account. (Log Out)

Facebook photo

You are commenting using your Facebook account. (Log Out)

Connecting to %s