What is an Email Header? Definition, Design Examples

Aug 25, 2022 - By Camilla Mackeviciute

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Email headers precede the email body.

However, the information that comes immediately after your subject, i.e., the line at the beginning of your email, is referred to as the preheader text.

The preheader text is one of the first items that your subscribers will see when viewing your emails. It summarizes the contents in the mail and can compel recipients or potential clients to open your email.

Definition of an Email Header

An email header is the section of an email containing information about the mails’ source, subject, sender, and recipient.

All email programs have a custom header consisting of (but not typically displaying) critical information for efficient email tracking and delivery. This information includes IP addresses, time-stamps, message ID, return path, and the senders ‘/recipients’ details.

You need to use a mail provider like Gmail, Yahoo, Office 365, or Microsoft Outlook to view a complete header.

The information contained in the header is critical to resolving common email problems such as emails not delivered or inaccurately marked as spam.

Why Do You Need an Email Header?

Email headers serve numerous essential purposes, including but not limited to the following:

  • Email Headers Protect Against Spam

The data contained in an email header help Email Service Providers (ESPs) to distinguish spam emails from legitimate emails.

ESPs analyze the data in the email header, more specifically the ‘received tag’ to determine the legitimacy of an email and decide whether or not the intended recipient should receive it.

Also read: Email deliverability: The Definitive Guide

  • The Message Header Simplifies Sender/Receiver Information

An email header contains information regarding the sender of the email and the recipient’s information. Most email markers will indicate this information in three fields including:

From. The message source, which includes the sender’s name and their email address.

To. It includes a recipient’s name and their email address.

Date. The specific time & exact date when the mail was sent.

Other parts of the email header are optional and can vary among email marketing services. However, the From, To, and date fields are mandatory in every email header! Should these fields be lacking in the header, you won’t be able to identify the emails’ source, sender, recipient, or even determine whether or not the email body is legitimate.

  • Email Header Allows You to Identify the Email’s Route

Once you send a new email from your computer, it’s transferred from a Sending Mail Server via the Mail Transfer Agents (MTAs) before reaching the intended recipient.

When the email passes through the MTA, the custom header is automatically stamped with the recipient’s information, date and time. This information helps your recipient to track the email’s route, including each MTA the email has traveled through before arriving at their destination.

Header information comes in handy when you want to identify or track down the source of a malicious or spam email.

Email Header Design

The email header is perhaps the most essential section of your email. Therefore, your email header design needs to be perfect to stun your customers and subscribers.

An email header is generally a form of art. This means that you can create or design a perfect email header that will automatically strike the interest of your audience and enhances email engagement

Emails used in email marketing campaigns are usually designed and decoded in HTML, and the header can consist of a navigation bar—depending on the purpose of the email. The header can also have an image banner or background.

Creating the perfect email header design is easy. You will easily find many professional tools for creating marketing and business emails.

These tools have a drag-and-drop email builder and a massive library of stock-free images allowing you to compose appealing email header designs from ready-made email templates in just a few minutes.

Here’s an example of email header design created on Sender email builder:


To design the perfect, thumb-stopping email header, you must ensure some key qualities. Below are the ‘do’s and don’ts’ of professional email headers:

The Do’s of Email Header Designs

  • Ensure the header is brand-identifying. The header should reinforce the ‘from’ field so that your recipient won’t second-guess who sent the email.
  • Ensure the header is versatile in that it can work with multiple email campaign types.
  • Create a simple yet elegant header without unnecessary information in your graphics, or crammed messages.

The Don’ts of Email Header Designs

  • Do not make it too big. The best headers are usually below 70px if they do not have a menu and less than 200px when a menu is included.
  • Do not overdo the navigation. Make the navigation as concise and straightforward as possible to avoid overwhelming the reader.

Also read: 7 Free Email Template Builders (HTML + Drag and Drop Editor)

Email Header Examples

When creating your email header, the most important thing is to ensure that it is brand-identifying and uses your logo. This makes your subscribers certain that they’re reading an email from your brand.

You want to also ensure that all the required header content is included and remains in compliance with anti-spam laws. Below are some of the best email header samples:

Dossier Uses All the Best Header Practices

Dossier’s email header makes perfect use of the preheader text. It makes sure that your readers won’t need to dig further into the mail to understand precisely what it’s all about.


Image source: Dossier

Dossier ensures that the preheader text is highly compelling, drawing the reader to the rest of the mail. In addition, Dossier integrates the best email header practices like easy-to-spot social media icons and a simple navigation menu, allowing readers to access everything they need with ease.

Delta Tells Everything at First Glance

Delta may seem basic and easy, but this email header is extremely effective. It features Delta’s logo, a three-option navigating menu, a very straightforward explanation, and a call to action.


Image source: Delta

With such clarity and ease of use, Delta also allows you to personalize your header, making it more inviting for your subscribers.

&Open Incorporates a Header Image and Loyalty Information.

&Open encompasses all the required email header information. On top of that, it allows you to include an emoji in your subject line- a novelty that’s also attention-grabbing.


Image source: &Open

In addition, &Open designed a very creative header image containing information about the company’s loyalty program. Your readers can click to find out how many points they have ensued, and they can also subscribe to the company’s services.

How to Read Email Headers

Below we have outlined a step by step guide on how to read a full email header on mail providers like Gmail, outlook, and yahoo:

View Email Header in Gmail

Step 1:  Click open the specific mail that you want to view the full header.

Step 2: Once the mail is open, click on the vertical three-dots icon that’s located close to the reply button.

Step 3: Navigate the drop-down menu and select ‘Show original.’

Step 4: You’ll be directed to a new window containing the complete header in its original HTML format. 

You should see the header information like authentication results and IP address.

View Email Header in Outlook

Step 1: Click to open the specific email that you need to view the header.

Step 2: Once it opens in a new window, select on the ‘File menu’ located close to the message tab.

Step 3: Scroll down and click on ‘Properties’ within the available menu details.

Step 4: You should be able to view your full header information, such as the IP address and more.

View Email Header in Yahoo

Step 1: Click open an email.

Step 2: Click the three-dots icon and find ‘more action’.

Step 3: Select ‘view raw messages’. You will see the full header information.

How to Get Email Header

Every single email received or sent on the internet contains an email header. A full and valid internet header provides detailed data of the network path taken by the mail from the sender to the recipient.

Email providers usually hide the full header, displaying only lines such as From, To, Date, Subject, Return path, etc. Generally, you will get your full email header in the following simple steps:

  • Sign in to your email on a new tab;
  • Click the specific email whose full header you need;
  • Click the 3 vertical dots close to the reply button;
  • Navigate the drop-down list and click ‘Show original’;
  • Another window or tab will open containing your full email header. 

Email Header Analyzer

Email header analysis typically involves using an email checker to get your full header and examine the fields that interest you. Below is how to analyze your email header:

  • Received Field

It shows the address of each computer or mail server that the email transferred through to get to the recipient’s inbox/computer. Unlike other details of an email header, the received field cannot be forged.

  • MIME-version

Multipurpose Internet Mail Extensions are internet standards of encoding that convert non-text attachments like images, audios, and videos into text, enabling them to be attached to the mail.

  • Message-ID

All message IDs are globally unique. This field is composed of a specific combination of numbers and letters generated to identify every email. Hence, no two emails can have the same Message-ID.

  • DKIM Signatures

Domain Keys Identified Mail, abbreviated as DKIM, is a standard that verifies the sender’s authenticity by linking the email with its domain name. It functions as a form of authentication technology that protects email senders and recipients from problems like being spoofed and phished.

Understanding Email Headers

An email header typically encompasses technical information about the sender, recipient, and email subject. Email headers allow efficient email tracking and delivery while protecting senders and recipients from spam and phishing.

Email Header Size

Email header size will vary depending on the template you’re using. If you’re using a desktop screen, the recommended email header width is between 650px to 700px, and the height should be 90px to 200px. When using a mobile screen, you should maintain a width of 350px and a height measuring up to 100px.

Email Header Explained

The email header, also referred to as the internet header is the section of code containing important information about the origin of an email and its destination.

Email headers the sender’s and recipient’s email addresses, and the subject line. Internet headers also include the brand’s name and/or logo—usually, the header design consists of a menu that links the reader to the brand’s website.

Email headers are great marketing tools, and sometimes, depending on the header design, the brand can include information about any perks being offered, for instance, discounts and free shipping.

Besides marketing email campaigns, there are many other benefits of using an email header. For instance, the information in the email header differentiates legitimate emails from spam emails while also allowing you to view the email’s source details and identify its sender.

If you’re looking for a powerful solution for moving your marketing means to the next level, consider Sender – the world’s most affordable and easy-to-use email marketing platform, with all top-tier features, including email, SMS automation.

Take Sender for a spin before shifting over from your existing email tool or start with zero financial commitment, the FREE Forever plan can help you do just that.

Also read: 

What is Interactive Email? AMP, Design Examples
What is Dynamic Email Content? Definition, Guide & Examples

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