All email inboxes are protected by filters that help to block spam and junk emails from unwanted sources. These filters work on a scoring system that grades incoming mail against undisclosed criteria to determine whether it is junk or not:


One or two triggers might still allow emails through, but if enough triggers are set off the email will not be received in an inbox.

Warning triggers include:

  • Sender reputation
  • Size of the email
  • Size of images inside the email
  • Heavy usage of images and links in the body of the email
  • Image-only emails without any accompanying body text
  • Very short or very long subject lines
  • 'spammy' / ‘red flag’ keywords inside subject lines
  • Email text / content that is not personalized (Dear [First Name Last Name], etc.)
  • Use of non 'web-safe' fonts
  • Unrecognizable sender information / email being sent by an intermediary

The good news is zkipster has taken steps to maximize the deliverability of your email invitations! One of these steps is whitelabeling your domain and email addresses. Find out how to set this up on your zkipster account in this article here.

In addition to this, is it very important that your email recipient list is clean and regularly checked. Most, if not all, email providers’ spam filters penalize your domain or IP with a higher spam score (meaning there is a higher possibility of your emails going to the junk folder) if they see that you are sending emails to bad email accounts. A bad email account is an address that does not exist, has been disabled or has a full inbox. These addresses should be cleaned (or “pruned”) from your email list regularly to avoid this. If you allow them to add up on your list, you will eventually be flagged as a spam provider.

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