Cross subdomain attribution for Contacts



Would really love some help here:
On our marketing website: we have a form where users can sign up to our web app.

Then, those users are redirected to the web app, which sits under a subdomain:

In the web app we have JavaScript events that fire according to specific actions taken in the web app. Those events do actually fire but they are not being attributed to the Contact and do not appear in the record of the contact.

There is also a similar form in the web app ( and where the form is under the same subdomain there are no issues with the JS events and they appear in the correct Contact’s record.

This leads me to believe there is a problem with the cross domain tracking.

Would love any assistance as this is forcing us to stop all our marketing campaigns.


Hi @Eyal_Katz,

Cross domain tracking limitations occur when visitors navigate from one domain (e.g. to another (e.g. This is because HubSpot uses cookies to track visitor identity, and cookies cannot be shared between domains. This is not an issue across subdomains (e.g. -> since cookies can be shared between subdomains.

This leads me to believe that there’s an issue with the cookie tracking of the first form; can you send me some more details on the form, and if possible a link to the page in question so that I can do some more troubleshooting?


Hi Derek,

It is a subdomain as the question itself implies.
I will share the form and domain in a private message.


Hi @Eyal_Katz,

Initially, I was able to reproduce the issue, but now I’m not seeing the same issues that I was. Let me continue to dig into this and I’ll get back to you here once I have some more information.