What is email deliverability, and what factors impact it?

Email Deliverability spam

Email deliverability is a term you may not be familiar with, but it’s an important concept to understand and master if you want to improve your communications strategy through e-mail marketing.

It’s often a mystery why some e-mails end up in the inbox while others are never seen. 

Why are your e-mail campaigns not working? Learn about e-mail deliverability to maximize the success of your campaigns.

What is e-mail deliverability?

Email deliverability is a term that describes the likelihood and ability of an e-mail to be delivered to its recipient without being rejected by ISPs (internet service providers) or spam filters, for example. 

When you send an e-mail to an acquaintance or a friend, there is a good chance that it will be delivered to his main mailbox. This is because it is a one-to-one communication, so it is not considered as spam by the various filters.

However, when you send a newsletter or e-mail marketing campaign, your distribution list is larger, and it will be more difficult to get your messages delivered to the inbox of everyone on your entire mailing list. 

This e-mail deliverability can vary depending on a number of factors. 

Factors that impact your deliverability 

For the good deliverability of your e-mails, you must take into account several factors. Indeed, there are many elements that can affect the way your e-mails are delivered to the recipients.  Let’s take a look.

Sender reputation:

Your sender's reputation will have a big influence on your deliverability rate and determine where your e-mail will land. The stronger your reputation, the more likely your e-mails will arrive in the inbox. Your reputation takes into account your domain name as well as your sending IP address.

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Message content: 

The structure of your message is as important as the content for your readers and ISPs. An analysis can determine if your e-mail is considered spam by the quality of the HTML code, the words used, the type of links, or the subject line you have used. 

Mailing frequency: 

To avoid being considered as a spammer, and thereby improve your deliverability, it is recommended not to send too many e-mails, and only for a limited time.
A high sending frequency could also increase the unsubscribe rate or the spam report rate. It’s preferable to target your messages with relevant communications and in line with the habits of your recipients.

Quality of mailing lists:

When you decide to launch an e-mail marketing campaign, it is important to consider the quality of your mailing lists. Are all your readers willing to receive your newsletter? Is your contact list up to date and verified? These will have an impact on your e-mail deliverability, and also on the bounce rate. A misspelled or incorrect e-mail address will cause a Bounce, which will impact your reputation and therefore your deliverability.


Is your open rate good? Do users ask to stop receiving your e-mails? Do users mark the messages as spam? These influence your deliverability. It is therefore important to monitor this information and avoid having high complaints or reporting rates from your readers.

Routing system:

The routing of your e-mails, that is to say, the solutions and services set up to distribute your messages during your communications, or marketing automation campaigns, as well as the authentications, have a significant impact on your deliverability. 
The goal of your routing is to accompany you so that your e-mails arrive in the inbox of your readers.