Every spam filter is a bit different, but generally they will all use similar criteria to determine what they consider as spam or not spam. The filter gathers up all the criteria they look for and they then assign a “spam score”—if the sum of all the factors is over certain score, the message will be marked as spam.
Below you will learn about the different criteria that spam filters look for, and how you can use this knowledge to see if there is anything that needs to be addressed in the content of your emails.
Much of this particular topic is addressed in this article here: How Can I Best Avoid My Email Going To SPAM?
That said, the main things to keep in mind are:
Keeping your image sizes in check. In general, we recommend keeping each image at or below 1MB in file size.
Make sure all of the links in the email function properly. You can check all your links on the 'Review' step of your marketing piece.
Avoid spammy language, particularly in the subject line. In addition, avoid using CAPS and special characters (!!!, %, #, &) in the subject line.
If your email does include images, make sure it also includes some text. A good 50/50 ratio of text to images, or two lines of text for every image is a good place to start.
Sent from address
Spam filters like to check and see where an email is coming from by looking at the ‘sent from’ address. Free email address (e.g. Gmail, Hotmail, AOL, etc.) are judged more strictly, so we recommend using a private company email address as your rezora username/sent from address.
One of the best things you can do is get yourself white listed.
Excess HTML Code
Spam filters can flag excess or sloppy code, extra tags, etc. The main thing to keep in mind here is to simply use caution when copying content from an outside source, as you can inadvertently bring in some excess code. We recommend following the format of one of your company provided templates, and adding your content manually to the pre-designed format.