Hi ​@Austin Chick - In Klaviyo’s native settings, the “Only show on certain URLs” and “Don’t show on certain URLs” rules do work for full or partial matches, so technically you can block forms on URLs containing specific UTM parameters by doing the following:

How to Block a Form from Showing on Certain UTMs

1. Go to Signup Forms → Edit Form → Targeting & Behavior.

2. Under Don’t Show on Certain URLs, enter a partial match pattern with your UTM parameter.

   • Example for utm_source=facebook: utm_source=facebook

   • Klaviyo will match any URL containing that string, even if other parameters follow.

3. Save & publish, the form will now not appear when that UTM parameter is present.

Use Wildcards or Multiple Values

• You can block multiple UTMs by adding each line separately in the “Don’t Show” list:

  • utm_source=facebook

  • utm_medium=paid

• If you have dynamic values, match just the parameter key:

  • utm_source=

  • (This blocks any traffic that has utm_source at all.)