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Email Delivery: What Is An X-Header?

Tracking and reporting on email metrics like sent, opened, clicked, bounces, and complaints are essential to managing email delivery. To aid in understanding these metrics, some email delivery providers (like us) offer the ability to add, track, and report on custom header values.

These are headers that are added into the message in addition to the usual headers like To, From, Subject, etc. These have traditionally started with “X-” to denote that the value is experimental or an extension. Hence, why they’re called X-Headers.

For all you techies out there, X-Headers are defined in RFC-822, but let’s take a look at this example from a Meetup notification I got

Dyn X Headers X Men
FYI : The X-Men have nothing to do with X-Headers.

this week.

From: Meetup
Subject: Meetups this week with: Climbers, Fun Hikers and
More!, and others
MIME-Version: 1.0
Content-Type: text/html; charset=”UTF-8″
Content-Transfer-Encoding: quoted-printable
Date: Mon, 4 Feb 2013 08:54:51 -0500

By itself, the values like X-MEETUP-RECIP-ID or X-MEETUP-TRACK might not look like much, but it means something to Meetup’s systems. If this happened to bounce, they know recipient id 71415272 had an issue and can ask in the app if my email address was correct, or some other valuable trigger.

If your email provider supports X-Headers, you can come up with your own values too, allowing a connection from your data to a specific message. This can be helpful in pulling reports by campaign, user, region, or whatever else you’d like to separate by. They also might come into play with postbacks, the GUI, or the API to allow different filters for reporting, or different values to return.

The real benefits of tracking X-Headers within email metrics begin to come when you separate campaigns, regions, or other special information and your email metrics. With this information, you’ll be able to optimize which campaign or region is providing the most opens or clicks. You’ll be able to quickly iterate and provide more optimized content and watch your conversions grow.

If you’re not currently using something like X-Headers to track your email, you might not be getting the most out of your email metrics. Instead of designing your own tracking system, this is another benefit that we can help with. Implementation Specialists, like myself, are here to help you understand how you can best use X-Headers for tracking, converting, and making your email program a success!

(Thanks to Mike Veilleux for contributing to this post.)

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Matt Torrisi
Whois: Matt Torrisi

Matt Torrisi is a Senior Solutions Engineer at Oracle Dyn Global Business Unit, a pioneer in managed DNS and a leader in cloud-based infrastructure that connects users with digital content and experiences across a global internet.

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