Deliverability tips for content


This article outlines some common ways that your content will affect your deliverability with the current trends in email deliverability.

General Rules

  • Use a recognizable sender name and from address
    Try to keep this consistent. From address should be using a domain name you own (do not use freemail domains!) with the authentication in order.
  • Encourage recipients to forward and reply to your emails, and remind them to add your email address to their contact book
    All of these actions have very positive metrics on your sender reputation and inbox placement.
  • Generally anything that our Spam Check flags might be a good idea to change
    If it says “Make lots of money!” for example, this means you have included language that resembles a "get rich quick scheme" and is likely to be flagged as spam.
  • Make it easy for recipients to unsubscribe
    The larger your unsubscribe font is, the better. This will help you avoid spam complaints which are 100x worse than an unsubscribe. Never try to hide your unsubscribe link—this will hurt your deliverability. On the contrary, users who unsubscribe do not reflect negatively on your deliverability.
  • Optimize your images
    Make sure that you are using optimized and compressed images in your campaigns. Heavy images can cause troubles: they trigger anti-spams and damage user experience. Try to keep every individual image under 50kb. You can easily achieve this by using JPGs instead of PNGs, and slicing any big image in smaller images and compressing them a little bit more.
  • Don't fret too much about spammy words like “free” and “100%”
    These don't typically have a big impact on deliverability. You should generally try to avoid them, but if your overall sending practices are good (good engaged lists) then you don't have to be too picky about your word choice—common sense is the best guide here.

Specific no-no's

  • Don't use link shorteners (eg, bitly)
    These are used heavily by spammers to mask their link destinations and are always listed on major blocklists.
  • Don't use a full HTTP link as the forward-facing text of a hyperlink
    For example, this is what you want to avoid in your emails:


    Using a full hyperlink as the forward facing part of a hyperlink looks suspicious, because there's no guarantee it actually redirects to that URL—it could just as easily redirect to another, malicious page. Instead, use simple text such as “Click Here,” or a descriptive sentence, and embed your link into that text. You can also include a button in your communication that links to your page.
  • Don't try to use an HTML form or any Javascript in your email
  • Don't include attachments

Common misconceptions

  • Text-to-image ratio is very important
    While it’s important to have a good mix between text and images, there’s no more a “right” text-to-image ratio written in stone. Our Spam Checker will even present a warning on the Campaign Summary page if your email seems to have a skewed text-to-image ratio. This warning is more of a suggestion and typically does not have a direct impact on deliverability. Just be sure you don't send a pure image email. There are still contacts who have images turned off by default in their email service provider.
  • Plain text ensures better deliverability
    This isn't true anymore. Most email filters care more about your sending history than the format used to send the message (HTML versus plain text).
  • The “sent on behalf of” or ”via” header affects deliverability
    It does not directly affect your deliverability. While there’s no negative effect on deliverability by leaving it as is, you are more than welcome to remove it: this might positively affect your brand recognition and, indirectly, improve your deliverability.


The more personalized you can make your email using conditional content and personalization tags, the better. Most email service providers can identify language that is targeted to the recipient. This especially applies to using personalization in a subject line or From email address. The more you can target your message to the recipient, the more likely the inbox is to think that message is important and belongs in the inbox.

If you've just migrated from another service and would like more information on maintaining good deliverability, check out this guide.

Was this article helpful?
16 out of 17 found this helpful

Have more questions? Submit a request

Start free trial