As an email sender, you’re probably used to creating amazing newsletter designs, segmenting your audience, and hopefully cleaning up your email list for maximum deliverability. however, one thing you might have missed is the email header. (not to be confused with the preheader, visible at the top of a newsletter).
Learning to read email headers and understand their content can help you fix deliverability issues, ensuring your sending reputation remains intact and your campaigns perform like a dream.
In this article, you will learn what an email header is, the different elements they contain and how you can read them, as well as how to view email headers in popular email clients.
so what are email headers?
The email header is invisible information that is sent along with your message. although it is not visible in the body of the email, both sender and recipient can see it in the raw message source in most email clients.
Some of the information in the email’s internet header is parsed by the recipient’s email client and is displayed along with the email, such as the sender’s address, subject line, and date.
The email client uses other information so that it can understand what kind of content the email contains, whether or not it is spam, and whether the sender is really who they say they are. Senders can also use this information to troubleshoot deliverability issues.
Although email headers are not visible immediately, with a few clicks in your email client you can view the content of any email header (we’ll show you how to do this below). here is an example of an email header view in the gmail webmail app.
You can learn a lot from an email header!
With a quick look at the email header example above, you can see that it contains much more than just the sender, recipient, and subject of the email. while these items are important, it is also possible to retrieve information about errors or security issues during submission.
Email headers are a great source of information when it comes to uncovering deliverability issues. Understanding what the content of an email header means allows you to determine whether or not your email reached its recipient without errors or changes, and if not, what caused them.
This is possible because the email header contains information about the isps and servers the message passed through on its way to the email recipient.
Learn more about email deliverability and why it matters in our guide.
standard parts of email headers
so we’ve talked about the types of information you can retrieve from the email header. now let’s look at the actual elements it contains, starting with the standard parts that all email headers have.
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from: the name and email address of the sender
to: the recipient’s name and/or email address
date: the date and time the email is sent
subject: the subject line of the email
no email can be sent without a sender, a recipient, and of course the time and date.
Below are the elements that allow you to analyze the technical details of the email!
additional parts of email headers
This is where things get interesting! these are the elements that allow us to retrieve information about the path of the message and the errors that may have occurred.
See our email authentication guide for more information on spf, dkim, and dmarc.
bonus: spamassassin email headers
If you’ve read our guide to spamassassin scores, you’ll know that when a spam check completes, headers related to your score are added to your email. there are several spamassassin headers, but the main ones to watch out for are x-spam-level and x-spam-status.
x-spam-level: The level header shows your spam level as asterisks, with one asterisk displayed per dot, rounded down. for example, if your spamassassin score is 4.3, your score will display as **** (four). if it gets a score less than 1, say 0.7, it won’t display anything.
x-spam-status: The status header tells you if your email is spam, with a simple yes or no. this is followed by your spamassassin score as a numerical value, eg 4.3. it will also show the required default score as well as the tests that were run.
Please note that spamassassin headers may not be visible depending on your email client. but do not worry! mailercheck can take care of that for you:
In addition to email list checking, mailercheck also includes email insights, the powerful feature that analyzes your email content and send settings before you hit send. it will also highlight issues that need to be fixed and get the spamassassin results so you don’t have to.
how to view your email header
Now that you know what to look for, you’re probably very curious to start checking your email headers! Fortunately, most popular email clients make it easy to verify the email header (although you may not see all of the information).
Let’s get started!
how to view email headers in gmail
1. open the sent or received email whose header you would like to see.
2. click the plus icon in the top right and select show original.
how to view email headers in yahoo! mail
1. open the sent or received email whose header you want to see.
2. click the plus icon and select view raw message.
how to view email headers in microsoft outlook
1. in your inbox or sent folder, right-click the email whose header you want to check.
2. go to view and then click view message source.
how to view apple mail email headers
1. open the sent or received email whose header you want to see.
2. go to view, then message and select all headers to see the full header of the email in the app, or source without process to view the entire email in a new window.
example of parsing an email header (gmail)
When you view the email header in gmail, it displays the email in a way that highlights the important parts of the header. this allows you to easily see the message id, date, sender, recipient, subject, and authentication headers (spf and dkim).
In this quick overview, we can see that the email was created on Wednesday, February 16 at 3:33 PM. m. by mailercheck. it passed the spf and dkim checks, along with the ip address and domain. let’s see what else the email header can tell us.
Scan your emails for better deliverability
congratulations! you can now analyze the technical aspects of an email header and identify potential delivery issues. you’re well on your way to sending campaigns that get maximum results every time.
If you want to streamline your email scanning and make troubleshooting more efficient, the best way is with an email scanning tool such as mailercheck. mailercheck not only pulls details from your email header information to identify problems, but also checks your email content for typos, broken links, and spam-like content.
Have a question about email header analysis? Let us know in the comments below!