25 How to improve your email deliverability_2

How to improve your email deliverability

Anyone who has ever set up a successful email campaign will agree: getting it right costs you blood, sweat and tears. Just about every aspect of a campaign influences its chances for success: design, content, tone of voice, subject line, responsiveness, and whatnot... There’s 101 things to be checked and double-checked along the way. And no, it doesn’t really end when the mail is ready to be sent…

Time has come to send out that planned email. But there’s more to that than just hitting the send button. What if your email fails to reach all the recipients it should? There go all your efforts, down the drain.

Landing in the inbox safely is a fundamental goal of all email marketing. These tips will give you a better insight in how this works and will help you improve the deliverability of your emails.
Here we go…

Is your email ready for take-off? Well, not quite. To help you see the full picture, let’s use ‘going on holiday’ as a metaphor for email deliverability, with the email itself as the traveler. Upon arrival at the airport, there a few security procedures, before the passenger can actually board the plane and head off on his journey. In this case, spam filters detect and isolate spam emails and infected content in the spam folder, based on predefined parameters.

Step 1: Check-in


Every traveler is identified by a personal passport or ID. Same goes for an email. The spam filter will scan if you – the sender of the email – really are who you claim to be. To prove your identity, a clear email authentication is required. By means of Sender Policy Framework (SPF), SenderID and DomainKeys Identified Mail (DKIM) it’s possible to prevent malpractices like phishing. Guided by these technical parameters, the spam filter will screen the domain name (i.e. @hotmail.com /@gmail.com /… ) and, when all is safe, tag it as ‘trustworthy’ sender of your email message.

  • The Sender Policy Framework (SPF) is an email authentication standard that compares the email sender’s actual IP address to a list of IP addresses authorized to send mail from that domain. The IP list is published in the domain’s DNS record.
  • The SenderID is an email authentication standard that compares the email sender’s ‘From’ address to the IP address to verify that it is authorized to send email from that domain.
  • DomainKeys Identified Mail (DKIM) was designed to help ISP’s prevent malicious email senders by validating email from specific domains.

In addition to these safety measures you can also set up Dmarc (short for Domain-based message authentication, reporting and conformance).

You should see your email as a letter inside an air mail envelope, when it’s about to be sent.
The email address of the sender (called the Mail-From header) is just as important as the email address of the recipient to make sure it arrives at its destination. After all, why do you put your own name and address on the back of an envelope? Exactly: to make sure it is returned to you, when the postman isn’t able to deliver it.

Something similar happens in email traffic. Whenever one of your emails is undeliverable at a certain address, it’s sent back to ‘bounce@xxx.xx’ (often referred to as the Envelope-From). This will often be a to standard email address (depending on the ESP platform), but it’s also possible to set up a Dmarc for this task. This implies that the Envelope-From will not be ‘bounce@xxx.xx’, but ‘return path@ yourdomainname’. In other words, using Dmarc, it becomes possible to trace back everything you send to your own domain, rather than the domain name used by your ESP (Email Service Provider). Which makes it your best defence against spoofing and phishing.

Most ESP’s will allow you to set up these technical elements. Be sure to get in touch with the administrator of your domain name to implement them correctly. 


Step 2: Safety control or screening


Travelers who have built up a negative reputation through previous incidents, probably won’t get past the security staff and the gate. And chances are they’ll never reach their destination at all. The same goes for your email message, as there is a reputation connected to it as well. This depends on two factors: the overall reputation of your domain name and the reputation of the IP-address from which it is sent. Did you provide a valid domain name and email address? Has your IP-address been blocked? Check, double-check and adjust if needed, to improve the deliverability.

The sender’s reputation is determined in a scoring system. Every organisation and ISP (Internet Service Provider) can assign a score to you. It goes without saying that giving your recipients a positive experience will significantly improve your sender reputation. One of the best methods to do so, is to have you recipients tag you as ‘trustworthy sender’.

Want to find out what your sender reputation is? Use one of these online tools:

You can find more info about Sender Score and the MX toolbox blacklist checker in this blogpost.

Always keep in mind that consistency is crucial to keeping your email reputation. For instance, a sudden increase in mail volume may harm your reputation, as recipients might see your mails as spam. Same goes for a too low frequency: the lack of data makes it difficult to analyse whether or not you are trustworthy. So try to keep the same pace throughout your campaigns.


As soon as the traveler has been clearly identified and the reputation has been checked, it’s time to scan the luggage. When there are things inside that shouldn’t be there, it could lead to missing the flight or even bring the holiday to an end.

Spam filters too, use certain content criteria to check if the content of your email might be considered as spam. So, at all times, be as relevant as can be to your audience. Write and read your email from the recipent’s perspective. Send only emails that your contact chose to receive. A crystal-clear opt-in procedure is crucial (and even compulsory in the light of GDPR legislation)

In addition to that, be sure to always offer your recipients the option to sign out of your email program. And avoid situations that make the recipient hit the junk mail button, rather than the unsubscribe link.

Don’t want your emails to get caught in a spam filter? Go easy on the use of exclamation marks or spam-sensitive phrasing (like ‘free’, ‘promotion’ or ‘discount’). And by all means, don’t use ALL CAPS. Make sure that your copywriter knows the game. Team him/her up with a professional who knows how to write solid, clean html coding and build technically sound emails, and you’ll never have to worry about spam filters.

Step 3: Safety instructions before take-off

How to self-test?

Once aboard the plane, it’s always wise to read the safety card. You never know… right? Just before sending it off, it’s always a good idea to do a simple final check. It will help you determine how well your email is likely to perform, based on trustworthiness and design.

It’s easy: send your email through the free testing utility of tools like Mail-Tester and get an instant insight in how email servers perceive your email message. Moreover, Mail-Tester will hand you free feedback and tips on how to improve the deliverabilty of the email you’ve just tested.


Your main goal as a traveler? Getting to your destination without hassle. Just like we want our emails to land safely in the mailboxes of our recipients. The aforementioned tips and techniques will help you make your email’s journey less bumpy. By offering a clear identification, keeping your reputation clean, offering recipient-friendly content and doing a smart final check, the deliverability of your email will improve significantly.

For more tips on email marketing, check out the RAAK whitepapers!

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Posted on
Sep 13, 2019