Deliverability seems to be a growing concern for many marketers, and this is not surprising. 54% of companies indicate that they have problems with deliverability. It is often unclear which factors influence deliverability. Yet it is often just a few of the factors that cause email delivery problems. Below is an overview of the most important factors. Take this into account in the design of your email marketing.

Wrong e-mail addresses:

Do not send e-mails to addresses where the message does not arrive (a hard bounce). Typing errors in the e-mail address are often the cause of this. Get these addresses from your database and make sure that you do not repeatedly send e-mails to these addresses that do not exist. With many Email Service Providers (ESPs) you can automatically arrange this in the software.

Complaint rate:

The complaint rate means the percentage of people who click on the "report spam" button when they open your e-mail message. Small fluctuations can already have a dramatic effect on your deliverability. It is therefore very important to deal with this directly (automatically). ISPs report to ESPs which people clicked on the 'report spam' button. ESPs capture this signal and then retrieve these e-mail addresses from your list, so that you keep a clean database.

Spam trap hits:

A spam trap is an old inbox that is no longer actively used by a natural person. However, this inbox has been reactivated by an internet provider, specifically to detect spam. When the ISP regularly receives e-mails from you in this spam trap, your deliverability will be drastically reduced. This problem will only occur when you have very poor list hygiene.

Relevance for recipients:

Relevance of the content to recipients is not only the most important success factor in email marketing, but also ensures higher deliverability. ISPs are changing the way they filter normal spam emails. More and more value is being placed on interaction factors such as the number of emails opened and the number of clicks. So we see a shift to more refined mechanisms, where your reputation and deliverability are (partly) determined by these interaction factors. So make sure that every e-mail campaign is of a high standard. Do you not have suitable content or message? Then postpone the campaign and send it when you can offer added value.


By implementing technical building blocks such as SPF, DKIM and DMARC you can prove to internet providers that you are the sender you are saying. Spammers regularly use fake e-mail addresses. When your e-mail message is verified and you have these building blocks implemented, internet providers know that you are the real sender. This benefits your deliverability. When authenticating your e-mail messages your ESP can support you.