Question from Reddit:
A bit lost here, my client has multiple domains which we target in the same google ads account. We want to set up conversion tracking. What is the prefered way to set up conversion tracking? Do you need multiple GTM containers and Gtags?
So far, we have the framework for the 1st domain ready, but I am questioning myself if we can use the same Gtag and GTM container for the second domain. There are differences in conversions, but we can create new conversions.
For example:
campaign 1 links to URL’s for domain ABC.COM
campaign 2 links to URL’s for domain DEF.COM
Answer from Nabil:
The short answer is:
You can absolutely use the same Google Tag Manager (GTM) container and Google Tag (gtag) across both ABC.COM and DEF.COM to simplify your setup, which is the preferred and most scalable approach for multiple domains under one Google Ads account.
You don’t need separate containers, but you must ensure your GTM is configured to handle cross-domain tracking and domain-specific triggers.
Specifically, you’ll need to update your Google Tag settings variable within GTM to include both domain names in the Domains to be Measured setting, and then use the Page Hostname variable in GTM to fire your conversion tags only when the user is on the correct domain.
The long answer is:
That’s a great question, and you’re thinking about scalability, which is smart.
For your scenario with ABC.COM and DEF.COM feeding into the same Google Ads account, the recommended approach is to use a single GTM container and a single Google Tag across both domains.
The core challenge you face is not the GTM setup itself, but ensuring the session continuity and the correct conversion firing logic.
By default, when a user clicks an ad for ABC.COM and then navigates to DEF.COM (or vice versa, if there’s a user journey that crosses domains), Google Analytics will treat that as two separate sessions, losing the original Google Ads click attribution.
To solve this, you need to configure cross-domain tracking within GTM.
This is done by editing your Google Tag configuration variable and listing both ABC.COM and DEF.COM in the Domains to be Measured field.
This setting tells the Google Tag to link cookies between the two domains, ensuring that a user’s session and the original Google Click ID (gclid) persist across both sites, guaranteeing correct attribution for your Google Ads campaigns.
For the conversion events, since you have different conversions on each domain, you will create separate Google Ads Conversion Tags within the single GTM container.
For example, you might have a Conversion - ABC.COM Contact Form tag and a Conversion - DEF.COM Purchase tag.
The key is in the Triggers.
Instead of just triggering on the thank you page path, you’ll use a Page Hostname GTM variable to create a more precise trigger.
For the ABC.COM Contact Form tag, the trigger would be Page Hostname equals ABC.COM AND Page Path equals /thank-you.
This ensures the correct conversion fires on the correct domain.
To make this entire system even more robust and resilient against tracking loss from browser privacy settings or ad blockers, which can sometimes interfere with the gclid persistence, an excellent solution is to implement server-side tagging using your GTM container connected to a service like Stape or Google Cloud Platform.
When a user clicks your ad, the gclid is captured on the server.
When the conversion happens, instead of relying on the browser to send the conversion tag, your website’s data layer or backend system sends the conversion details and the persistent gclid to your server container via the Google Tag Manager client.
This server container then uses the Google Ads API to send the conversion directly to Google Ads, guaranteeing that the conversion is attributed correctly with zero data loss due to client-side issues.
This setup offers superior accuracy and reliability for all your cross-domain conversion tracking.
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