How can content affect email deliverability?

This article describes some common ways in which your content affects deliverability. The relevance of your content is always the most important aspect of your deliverability, but there are also a few other points to consider.

General rules

  • Use a recognizable sender name or sender
    When your recipient recognizes your address or name, the chances of opening the email are significantly higher, so try to be consistent in this. When communicating on behalf of an organization, you can make good use of this by, for example, emailing on behalf of a specific colleague depending on the subject.
  • Encourage recipients to forward and reply to your emails, and remind them to add your email address to the safe sender list
    Sharing an email is a very clear signal for email providers that you are sharing valuable content with your contacts. This will be taken into account when sending your next campaign. When a contact adds you to their safe sender list, it guarantees that the shared content is trustworthy. As a result, your emails will no longer end up in spam. You can read more about this in this article.
  • Make it easy for recipients to unsubscribe
    Although you work hard for your contact list, it is important to make unsubscribing easy for your contacts. The more difficult this process is, the greater the chance of a spam report, which is much worse than an unsubscribe. Never try to hide the unsubscribe link. Additionally, keeping your lists clean is helpful. The percentage of contacts that open your emails is more valuable to an email provider than the actual number. A high open rate means that your emails are less likely to end up in spam.
  • Don't worry about words that contain spam, such as 'free' and '100%'
    These generally do not have a significant impact on deliverability. In general, it is better to avoid them, but if your general sending practices are good (engaged lists), you don't need to be too picky about your word choice - common sense is the best guide in this choice.

Specific no-go's

  • Avoid using link shorteners (e.g. bitly)
    These are commonly used by spammers to mask their link destinations and are always listed on important blocklists.
  • Avoid using a full HTTP link as the visible text of a hyperlink
    For example, this is what you want to avoid in your emails: 
    Using a full hyperlink as the visible part of a hyperlink looks suspicious because there is no guarantee that it actually redirects to that URL. The link can just as easily redirect to another malicious page. Instead, use simple text like 'Click here' and embed your link within that text. You can also include a button in your communication that links to the correct page.
  • Avoid using HTML forms or JavaScript in your email
  • Do not attach files
    Attachments cause the file size of your email to increase significantly. Large files are more likely to end up in spam. If you want to share documents via email, you can use our Content Manager instead.

Common Misconceptions

  • Text-image ratio is very important
    While it is true that images can impact deliverability, this rarely happens in practice. Our spam check even warns you if your email seems to have a skewed text-image ratio. This warning is more of a suggestion and generally does not affect deliverability. However, make sure not to send image-only emails, as there are contacts whose email providers have images disabled by default.
  • Plain text leads to better deliverability
    This is no longer true. Most email filters care more about your sending history than the format used to send the message (HTML versus plain text).
  • The header 'sent on behalf of' or 'via' does not affect deliverability
    It does not impact the deliverability of your email, so you can use it without any issue if you wish.


The more personalized you can make your email with conditional content and personalization tags, the better. Most email service providers can identify the language targeted at the recipient. This is especially true for using personalization in a subject line or 'From email address'. The more you can tailor your message to the recipient, the greater the chance that the inbox will consider the message important and deserving of being in the inbox.

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