I am trying to pass UTM parameters from my site into HubSpot so they are stored on the contact after a visitor books a meeting through an embedded HubSpot Meetings form.

The Meetings tool is embedded inside an iframe. The page URL contains valid UTM parameters, for example:

https://example.com/book?utm_source=google&utm_medium=cpc&utm_campaign=test

The meeting booking works, but none of the UTM values are saved on the HubSpot contact record.

I have searched the HubSpot documentation, developer forums, and existing Stack Overflow questions, but most solutions apply only to regular HubSpot forms, not the Meetings tool.

Below is the minimal reproducible example of what I am using.

1. Original Meetings iframe embed

2. Iframe after adding UTM parameters from Cookies

Even after manually appending UTMs to the iframe URL, HubSpot still does not record them.

3. Tracking code with identify()

I also tried sending UTMs to HubSpot using the tracking API.

Expected behavior

The UTM values should be stored on the HubSpot contact once the meeting is booked.

Actual behavior

The meeting is booked successfully, but no UTM values are saved in the contact record.

Question

Is there a supported method to capture UTM parameters and save them to the contact when using a HubSpot Meetings form embedded in an iframe?