Email Engagement

X-Headers: What They Are and 13 Ideas on Using Them to Measure Email Marketing Performance

minute read

Over the past several years I reviewed the deliverability and reputation of many marketers. While every company has their strengths and weaknesses when it comes to general deliverability best practices, one needed improvement stood out: how to measure campaign performance. The data gathered and interpreted in most cases only tells part of the story and often leads to marketing managers scratching their heads wondering why performance is slipping over the past quarter.

I’m sure most marketers use URL tagging to track email performance via Google Analytics or other leading web analytics software. URL tagging can give you great information of subscriber behavior on your website so take that next step and complete the data circle so you are making decisions based on the full picture instead of just pieces of the puzzle.

What is my first step to improving my performance measurement?

Assuming you have a good grasp of your goals for using the email channel, you need a mechanism that enables you to monitor the behavior of each subscriber and collect the data. This is accomplished by implementing an “X-header” in to every email you send. An “X-header” is basically a string of letters and numbers that is placed in every email you send that gives specific information you can tie to subscriber behavior.

For those of you that use an Email Service Provider (ESP), chances are they already do this for you or can do this for you, so make sure you fully understand what data is being gathered and what it means to your business. If you send your own email, it’s time to go talk to the IT person that administers your email servers. Tell him or her you want to place an X-header in every email and use that information to improve performance. When he or she asks you what you want to put in the X-header, I generally recommend four categories:

  1. List Source: Where did the subscriber come from? (e.g. your website, POS, co-registration partner, event)
  2. List Segment: What is the name of the subscriber segment?
  3. Campaign: What is the name of the campaign?
  4. Subscriber ID: This is an ID you can use to reference the email address of the subscriber in your database since most ISPs will redact that information in the complaint feedback loop process.


Below is a basic example of how an X-header is structured and how you can put information in it that you want to track.

  • X-CompanyID: <List Source><List Segment><Campaign><Subscriber ID>
  • X-CompanyID: WebsiteSignUpPriorPurchasers3MonthsNewProductLaunchWidgetSubscriber123

The end result will look something like this:

    • X-CompanyID: WSUPP3MNPLWS123


You now have an X-header, so here are 13 Ways to use it for your business:

    1. Link deliverability, response and web analytics metrics


    1. Measure the quality of your co-registration subscribers through complaints, unknown users, rejections and spam traps


    1. Troubleshoot deliverability problems


    1. Track leads from events


    1. Track performance of your testing program


    1. Measure the success of your email campaign


    1. Track the launch of a new product


    1. Find out when subscribers stop engaging with your email campaigns


    1. Identify which subscribers respond the most through the email channel


    1. Measure performance of re-engagement campaigns


    1. Improve lead scoring and lead nurturing


    1. Identify the best source of buyers


    1. Track performance of different landing pages for different segments


Implementing a comprehensive tracking program takes time, so start simple and work your way up as you learn more about the metrics that matter to your business. Once you have the basic tracking down, incorporate it with your testing strategy. In time you will see the full picture of your email program and be able to make better decisions that can help you reach your company’s goals.