Deliverability refers to ensuring email messages are delivered and aren’t blocked by spam filters because the email content or structure falsely identifies a permission-based email as a spammer, or because the sender’s IP address has a poor reputation for spam (definition by D. Chaffey).

This article addresses all key ingredients that will help you maintaining a healthy sender reputation and deliverability.

Split-run testen

Relevant e-mails generate the least unsubscribes and the most opens and clicks. Since those are good for the reputation of your sender domain, you want to know which content and styling works best for your target audience. Therefore Copernica provides the possibility to run a split-run test. In a split-run test you send different versions of an email to a smaller group to determine which version gets the best results. You can then send the best version to the rest of the database.

E-mail authentication

To be able to distinguish legitimate e-mails from the relentless flow of spam messages, large mailbox providers, including Google, Microsoft and Yahoo have developed technical tools with which you can be identified as a trusted sender.

Sign your emails with DKIM

DKIM stands for DomainKey Identified Mail and puts a unique digital signature in the invisible header of your emails that is checked against the signature in your DNS. DKIM helps email providers validate that an email was really sent by you and isn't not forged or forwarded by some obscure party.


SPF validates the invisible sender address (the envelope address). You only need to configure SPF if you use a custom envelope address. For most users, this is not the case, and the SPF is automatically set correctly.


DMARC is technical entry that you include in the DNS record of the sender's domain of your emails. With this (fairly new) policy, you inform receiving mail servers that you utilize SPF and DKIM.

But what makes DMARC even more powerful is the fact that it allows you to tell the receiving mail server what it should do with emails that fail the DKIM and SPF test.

It is even possible to receive daily reports about emails that have been rejected, enabling you to improve your settings.

More info on

Subscribe to feedback loops

Tell ESP's how they can inform you when a subscriber marks your email as spam with feedback loops.

Use your own pic-register domain

When sending an emailing with Copernica, all of the clicks, impressions and images of this emailing are processed by dedicated servers. These servers are accessed through a specific domain name: the pic-register domain. Due to actions of our users (exclusively), a pic-register domain sometimes ends up on a blacklist, because they have sent malicious mails through these servers.

Copernica is provided with several default domains that you can choose from. But we advise to set up your own pic-register (sub)domain. This will make your reputation invulnerable to the (bad) actions of some of our users that misuse our software, or by the actions of anti-spam parties that are way too easily agitated.

A pic-register domain is set up easily. Most peope create a subdomain under their company domain (e.g., Point the (sub)domain to using a CNAME. Then go to the delivery settings of your account and enter your own domain at the pic-register settings, replacing the old one.

The delivery settings can be configured from your account dashboard on

This is also particularly great for white labeling and for gaining user trust. Recipients will see your company domain when they hover links in your emails, and not ours. Wouldn't you be suspicious if a company linked you to another company's website?

Optimize your database and email documents

ESPs do not like it if you keep sending them emails to mailboxes that no longer exist, to people that have unsubscribed from your list or try to deliver emails that continuously result in delivery errors.

Automatically process email bounces

It may happen that an email address for any reason ceases to exist. When a delivery attempt results in a bounce, it is automatically registered by Copernica. On this information you can make selections in your database enabling you to take further action using followups.

Use double optin for new subscribers

With double optin a new subscriber asks to be subscribed to the mailing list, but unlike single opt-in, a confirmation e-mail is sent to verify it was really them. In this way the person who subscribes always is the same person who will be receiving the emails. You will not be sending to non-existing email addresses. It also keeps your database clean. See also the tutorial on creating a double opt-in.

Create the lowest possible spam score

Spam filters and email service providers test incoming mails to validate whether it is spam or not. The higher your spam score, the more likely your emails will get trapped in recipients spam folders. Keep adjusting your email document to reach a spam score lower than 0.2 for the best delivery results. You can check your documents spam score by clicking on the warnings in the bottom of your active document. You can find more tips on lowering your spam score in this article.

Do not hide unsubscribe links and make sure that they work

It is important (and required by law) to always add a working, visible unsubscribe links to your newsletters. If you make it very difficult for subscribers to unsubscribe, they will use the spam button rather than your perfectly hidden or non-working unsubscribe function. They do not want to receive any more information, and you do not want to be marked as a spammer, so make sure your link is working and visible.

Unsubscribe links can easily be placed with a Smarty tag or by simply dragging one onto the template in the Marketing Suite drag 'n drop editor. You can set different unsubscribe behaviours, including the behaviour to keep the profile but not send emails anymore.

Another way to optimize your HTML email document is a collaboration between Google, Yahoo!, Bing and the Russian search engine Yandex and more and more adopted by email clients. Add micro data to your email documents to exactly specify what your email is about.

Last but not least: send great content

Probably the most important one in this list and we can't stress it enough, because we have seen too many of our users having utilized all of the above and still getting poor delivery results. If nobody is reading your emails, discarding them without even bothering opening it, ESP's will lower your sender reputation significantly.

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