Spam filters are designed to remove junk out of your customers’ inboxes, but they’re sometimes so good that they may sweep away your valuable emails, too.

List of spam trigger words

If your email has all caps

If your email has exclamation points

If your email image to text ratio is high

Low open rates (in case you use your own domain)

You can’t afford to let your emails get flagged as spam, so keep reading.

Sometimes the words you choose are what’s keeping you from reaching your prospect.

This applies most to your email subject line. Words like “free,” “money,” “help” and “reminder” all trigger content-based email spam filters. Especially if you’re not added as a contact in your recipient’s email database.

Here’s a more complete list of email spam trigger words:

Want even more? Here’s a list of 202 common spam words.

Do you think this is a nice subject: IF YOU WERE A FISH, WOULD YOU SWIM RIGHT INTO A NET?

We didn’t think so. Using all caplocks in an email is game-over just the same.

How excited are you about avoiding email spam filters?!?!?!

Like emails with all caps, emails with exclamation points are food for spam catchers. Especially when they’re in the subject line.

Because messages with exclamation points resemble true spam emails looking to scam recipients, they are treated the same by email providers. They’re filtered from inboxes.

It’s the similarity principle. In this case, people have set systems to group emails based on similarities that they have.

Here’s how an email that’s fallen victim to a spam filter shows up in the dark depths of a recipient’s spam folder:

The takeaway: No exclamation points in your subject lines. When you have a minute, also take a look through your own “Spam” folder for patterns to avoid in your own emails.

Messages that are overly graphic will not reach your recipient. Salesforce says so. Your email needs to be more than just an image or many images with little text.

Note: The common rule of thumb used to be to maintain a 60/40 text-to-image ratio. But recent research from Email on Acid shows that restrictions like this depend on the length of an email.

Their findings:

To give you an idea of what a 500-character email would look like, this message is exactly 500 characters (with spaces).

Emails of this length are typically 5 to 7 sentences long. They give you enough room to introduce yourself, describe why you’re reaching out plus what value you offer, and then request something. Just like that.

Because sales emails today are kept short in order to draw a prospect’s attention, keep it, and quickly drive action, they often fall within this 500-character range.

The takeaway: Emails with a graphic and no text just about guarantee your email will never see the light of day on the other side. If your email is at or under 500 characters, A/B test it. Use a bulk email tool to split up your recipient list into two.

Send the first batch a version with an image, and the second a version without an image. Track campaign performance to see if you have higher opens with one versus another. (Most email platforms don’t measure email spam rates, so you have to infer spam rates from open rates.)

You can also try a free tool like mail-tester to audit your email before sending.

Check this article first on How to set up your Outbound Domain

Webmail providers like Gmail are increasingly using recipient engagement to classify an email as spam or not. It’s called “Engagement-Based Spam Filtering.” They identify when a user deletes unopened emails from senders, and begin to filter out these emails from reaching the inbox in the first place.

The takeaway: If you’re sending emails to someone over and over without any opens, then stop. It’s a wasted effort. Use an email tracking tool to see whether emails sent from your company account are getting opened.