How to avoid spam filter triggers

Modified on Wed, 04 Jan 2023 at 03:22 PM

A good email subject line can increase your ticket sales or Spotify plays of your new album. A bad subject line will trigger spam filters and ruin your sender's reputation.

Follows these best practice tips to avoid spam filters and protect your reputation.

Things to avoid
  • More than 8 words or 60 characters
  • More than one emoji
  • ALL CAPS and too much punctuation !????!!!!
  • Spam trigger words  

Keep it short
Attention spans are short and mobile phones display limited amounts of text. We recommend your subject line is no more than 8 words or 60 characters.

One emoji per subject line
Emojis can increase your open rates and help you stand out in the inbox if used correctly.

  • Use ONLY ONE emoji per subject line - research has shown more than one reduces your open rates.

  • Keep it relevant - consider if an emoji adds value to your subject line and if it will resonate with your audience. 

  • Test, test, test - newer emojis may only render on certain operating systems. Ensure you send out a few test emails before sending them to the entire list.


Excessive punctuation and ALL CAPS
Don't scream at your customers. A subject line with too much punctuation or that is using all caps will trigger spam filters.


Don't forget about the preview line
The preview line follows the subject line. It is often forgotten and auto-filled with text like "Image" or "View this email in your browser"

  • Remove the alternative text from images at the top of your email, as this will fill in the preview line.

 Avoid spam trigger words
If you use too many of these words in your subject line and or email body, it's likely to trigger a spam filter. This list is not exhaustive but gives you an idea of what to avoid.

  • Free

  • WIN

  • Discounted

  • You Won!

  • Prize

  • Save Up to

  • Get it now

  • Exclusive deal

  • Limited time

  • Order now

  • This won’t last

  • Winner

  • Winning

  • You are a winner

  • You have been selected

  • Congratulations

  • Bonus

  • Fantastic

  • Lifetime

  • Luxury

  • Unlimited

  • Score

Was this article helpful?

That’s Great!

Thank you for your feedback

Sorry! We couldn't be helpful

Thank you for your feedback

Let us know how can we improve this article!

Select atleast one of the reasons

Feedback sent

We appreciate your effort and will try to fix the article