a key point of a deliverability strategy

What are we talking about when we talk about an email header? Mailing is one of the most effective digital marketing tools. That’s why 70% of companies use it to promote their services or products to their customers. However, an emailing campaign is not just about sending emails. A number of factors must be taken into account for the mailing to be successful. The header of an email is one of them. It is an important tool to solve the spam and deliverability problems of your newsletters. What is an email header and what are its purposes? How to display it according to your Webmail? Explanations.


#1. Email header: definition

email header
email header

An email is made up of three major components : the header (or header), the envelope and the body of the message. The latter includes all the content of the email (text and images).

The envelope refers to the information used by the server and the messaging provider to deliver the message to the correct address. It is invisible to sender and reader.

Finally, the header of the email contains elements concerning the sender and the recipient of the message :

  • the email addresses of the sender and the recipient(s);
  • the subject of the email;
  • the date and time of sending;
  • the servers concerned during the transmission of the mail between the sender and the recipient.

The default configurations of most messaging systems do not allow the sender or the recipient to fully see the header. However, it is important to know the process of sending an email.

Finally, note thatit is possible to customize the header mail with company logo For example. THE best email software offer different header models.

#2. Objective: resolve deliverability issues

resolve deliverability issues
resolve deliverability issues

The header provides information on the different stages of the transmission of the email (Internet Service Providers, servers, emailing tools). It also allows to check if the email is secure and has arrived safely in the recipient’s inbox. The user can then check if the message has been delivered or if it has encountered an obstacle. He can thus determine the source of the problem and solve it.

Headers solve a number of problems with sending email. This is why it is essential to properly configure the send settings when managing a email campaign.

#3. A section of the email full of information about the shipment

There are several templates for email headers, but they typically include the following information:

  • sender’s name and email address : they appear in the “From” section;
  • the recipient’s email address and name in the section “To”: when the message is addressed to several recipients, the name and e-mail address of each of them appear there;
  • the day and time the email was sent (“Date” section);
  • the subject of the email (“Subject”)
  • the return path : if the message cannot be delivered or if a problem occurs, the mail is sent to the address appearing in this section. This is usually the address mentioned in the “From” part;
  • a “Received” section : it contains technical elements specific to the sending of the mail (IP of the sender, electronic address of the recipient, name of the mail server, etc.);
  • the identifier of the email (“Message ID”) : it is unique for each e-mail message;
  • a “MIME-version” field (Multipurpose Internet Mail Extensions) : it indicates the programs that support attachments;
  • the type of content (“Content-type”) : this line indicates the different content formats present in the email (JPEG, text, etc.).

To have : How to make a mailing?

Display email headers according to your mailbox

All email providers display a header for each email sent. However, these latter are not directly visible to users. But then, how to view the headers of e-mail messages? Here is how to proceed for the main webmails.

To have : Responsive email


On the site Internet Microsoft Outlookmeeting on the three points at the top right. Choose the option ” View message details “.

If you use theoutlook email mobile app, double click on the message so that it is displayed in an independent window. Then select ” File “, Then ” Properties “. Header elements appear in the “Internet Headers” field at the bottom.

To have : Outlook Mail Merge


In google mailsimply click on the three dots located at the top right of your email. The mention the reference ” More appears when you hover the mouse. Then select ” Show original “. The header will be visible in a new window.


In yahoo mail!, also click on the three dots at the top of the email. Choose ” Show message in plain text to bring up the header.


If you use Apple Mailopen the email, then choose the “ Presentation ” in the menu. Then select the ” Message “, And ” All headers “. You will see the message header appear.


What is a pre-header in emailing?

Initially, the pre-header was the first text of an email. It was in a preview window or above the message body.

From now on, the pre-header designates a short text that comes just after the subject of the email. It shows up in the mailbox queue. It completes the subject of the message in order to encourage its opening. It is generally not visible when reading the email.

What is email deliverability?

The term ” email deliverability » is used for qualify the ability of an email to reach the recipient’s inbox. It was then only neither blocked, neither deleted, nor classified as spam. The deliverability rate can be affected by different factors :
an incorrect email address;
poorly targeted contacts;
an outdated mailing list;
the absence of SPF, DKIM, DMARC identification protocols;
a bad sender reputation;
a blacklisted IP address;
a high spam complaint rate;
non-compliance with antispam standards (use of spamwords, soliciting messages, etc.)
source code issue;

By mailing, the deliverability rate is a very important performance indicator. It actually allows you toassess the relevance of your content and your reputation as a sender.

How does an email header protect against spam and phishing?

The header of an email has information about the journey of the email from the sender to the recipient. This data allows email providers toidentify spam and phishing attempts. They can then determine the reliability of the message and decide whether or not to forward it to its recipient.