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Clean up your contact lists to improve email deliverability

Last updated: January 29, 2024

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Each contact in your database should be organized based on why they expressed interest in receiving marketing emails from you. You can refer to this data to ensure that your marketing email content is right for your audience.

Email engagement also improves your inbox placement rates. Email senders with high rates of opens and clicks look more trustworthy to email security filters. And most email accounts, including Gmail, automatically filter out emails that recipients aren't opening or clicking

If you send an email from HubSpot that results in a high rate of negative engagement (e.g. bounces, spam reports), your email account will be placed in a suspension state. To resolve the issue, create lists to segment your contacts based on their interests and original source. Then suppress or delete any outdated or unengaged contacts from your account.

Please note: if you have questions about your contact lists after reviewing these recommendations, reach out directly to your Customer Success Manager or start a conversation on the HubSpot Email Deliverability Forum on the Community.

Best practices for adding and maintaining contact lists

Segment your contacts

To clean up your contact lists, use any of the following contact properties to get more context about their original source and why they're engaging with your business. 

  • Create date
  • Last email date
  • Recent conversion date
  • Last form submission
  • Last email opened
  • Last email clicked
  • Last reply
  • Last date purchased
  • Last activity date 

If any of the above properties are unknown or more than one year old, refer to best practices about confirming opt-in consent.

Create and suppress a list of contacts who've never opened one of your marketing emails

Without taking action, low open rates of your marketing emails can often worsen over time. Email service providers like Gmail or Outlook will move emails with low engagement to the spam folder, which can lead to open rates dropping further, since fewer users will see your emails once they're filtered out of their inbox.

To prevent this process and improve your overall open rate, you can create and suppress a list of contacts who've never opened one of your marketing emails:

  • In your HubSpot account, navigate to CRM > Lists.
  • In the upper right, click Create list.
  • In the top left, click the pencil icon edit and enter a name for the list.
  • In the Filters section, configure the appropriate filters:
    • To segment contacts who've never opened one of your emails, select Contact property Last marketing email open date, then select is unknown.
    • Under the filter you just created, click AND.
    • To avoid filtering out brand new contacts, you can set a minimum threshold of emails received before you deem that the contact is unlikely to open any of your emails. Select Marketing emails delivered, then select is greater than. Enter the number of emails you'd like to set as a threshold.
  • In the upper right, click Save.


You can then suppress this list of contacts when you're configuring your email's recipients.

Low quality contact sources

Any contacts from the following source types should be removed from your database, as emailing unengaged or unknowing contacts can damage your email sending reputation:

  • Event attendees from a conference or trade show
  • Guessed emails based on the company format
  • Rented, borrowed, leased, appended or purchased lists 

Please note: purchased lists should be deleted from HubSpot immediately or imported as an opt-out list to ensure they're automatically dropped from all marketing emails.

Here are some important points to consider when looking at contacts from these sources:

  • Many of these sources contain spam traps, which are emails deliberately planted to help email service providers identify spammers. 
  • Reaching out to contacts from these other sources is also a direct violation of our Acceptable Use Policy and may violate privacy or data laws in your jurisdiction.
  • A spam complaint rate of 0.1% on a single email is a red flag that will increase your chances of bouncing or landing in the spam folder.
  • Even a lack of enthusiasm among your recipients can do damage to your sending reputation, as a marketing email with an open rate lower than 15% sends a message to email service providers that the sender is sending spam. 
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