How do I prevent spam form submissions?

Last updated: January 10, 2017

Available For:

Marketing: Basic, Pro, Enterprise
Sales: N/A

Each time an email address is entered into the email field on a HubSpot form, the address is immediately validated by HubSpot. This functionality is built into all HubSpot forms and does not need to be enabled. If the email address is not valid (does not exist, is misspelled, etc.), the user will not be able to submit on the form.

There are also a few methods to provide additional protection against spam form submissions:


CAPTCHA gives you an added layer of protection against spam form submissions. It adds a step to your form, requiring visitors to verify that they are not a robot before submitting. To learn more about CAPTCHA and how to enable it on your forms, check out this article

Block free email providers or specific domains

In addition to enabling CAPTCHA, you may also want to add additional validation to the email field on your form to encourage your visitors to provide high-quality business email addresses. To do so:

  • Navigate in HubSpot Marketing to Contacts > Forms.
  • Click on the name of the form you need additional validation for to edit it. Then click pencil icon to the right of the Email field.
edit email field pencil icon
edit email field pencil icon
  • Now you will see a couple of options for adding further validation to your email field:
    1. Email Domains to Block - this is useful if you have received spam submissions from a particular domain in the past (or if an email domain that you want to block is not covered by the second option below)
    2. Block free email providers - you should use this if you only want submissions from domains associated with businesses, etc. Click the See list link next to this option to find out which free providers will be blocked.
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  • Click Done Editing when you are satisfied with your changes and then Save form.
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