What is graymail and how can I avoid sending email to unengaged contacts?

Last updated: November 14, 2018

Marketing Hub Professional, Enterprise

Applies to:

Marketing Hub
Professional, Enterprise
Legacy Marketing Hub Basic

Graymail is email that your contacts have opted to receive, but don't actually engage with. By reducing the amount of graymail you send, you can improve your email sending quality and score. Over time, you will see higher engagements and open rates from your contacts since you are sending to people who are more interested in your content.

How does graymail affect my sender reputation?

Internet Service Providers (ISPs) learn how contacts are engaging with your emails and become better at categorizing them over time. For example, if a contact opts in to receiving your marketing emails, opens one and then doesn't open the next 20, ISPs will begin to automatically categorize your emails as graymail. 

If you continually send to contacts who don’t open your emails, you’re reducing your engagement rates. This damages your sender score reputation, which hurts your ability to deliver to people who do want to hear from you. By suppressing unengaged contacts, your sender reputation will improve over time, eventually increasing the likelihood of your emails ending up in your recipients' inboxes.

How can I avoid sending emails to unengaged contacts?

HubSpot includes a graymail suppression feature that uses the Sends since last engagement property to automatically suppress a list of contacts who have not been engaging with your marketing emails and helps prevent them from becoming graymail. You can control whether or not this feature is enabled by default for new or cloned emails in your email settings:

  • In your HubSpot Marketing Basic, Professional, or Enterprise account, navigate to Content > Content Settings.
  • In the left sidebar, select Marketing > Email, then select the Subscriptions tab.
  • Scroll down to 
  • Switch the toggle ON to enable this feature for newly created or cloned emails by default. This feature is automatically enabled by default.

To enable this on a single email:

  • In your HubSpot Marketing Basic, Professional, or Enterprise account, navigate to Content Email.

  • Click the email name or click Create email.
  • Add your content and set up the details of your email, then click the Recipients tab at the top of the email editor.

  • Ensure that the Don't send to Unengaged contacts box is checked.

You can also use this feature with automated emails:

  • In the email's Recipients tab, select Save for automation.
  • Ensure that the Don't send to Unengaged contacts box is checked. This will prevent the email from being sent to contacts with low engagement even if they are enrolled in your workflow.

Emails that have been sent or saved for automation using the graymail suppression feature will indicate Enabled under Don't send to contacts with low engagement in the email details. 


You can see which contacts were excluded from a specific email send using the graymail suppression feature by clicking the Recipients tab on the email details screen and selecting Not Sent, and then looking for the recipients labeled as unengaged.

How does HubSpot calculate unengagement?

A contact will be categorized as unengaged if they meet one of the following criteria:

  • Have never opened a marketing email from you and has not opened the last 11 emails you've sent them.
  • Has previously opened a marketing email from you but has not opened the last 16 emails you've sent them.

How can I re-engage these contacts?

Clicking the Unengaged contacts link in the Recipients tab of the email editor will bring you to a smart list of contacts who meet the criteria above. There may be quite a few contacts who end up being excluded from your sends. This does not mean that they are ineligible. Instead, it's a great opportunity to create a re-engagement campaign to connect with these recipients again and potentially convert them into customers in the future. Check out this HubSpot project for more detailed steps on how to make your re-engagement campaign successful, and read more about how to optimize your emails for better engagement here.

Want to learn more about graymail? Check out this blog post.