Google Ads Cross Domain Tracking

Google Ads cross-domain tracking is required whenever a user's journey from ad click to conversion spans more than one domain — a common scenario in e-commerce sites with third-party payment processors, businesses with separate landing page domains, companies using hosted booking or checkout tools, and organisations with microsites or regional domain variants. When a user clicks a Google Ad on domain-a.com, then completes a purchase on checkout.domain-b.com, the conversion happens on a different domain than the one where the click landed. Without cross-domain configuration, this purchase is invisible to Google Ads, the conversion is lost, and the GCLID that would credit the ad click is not passed across the domain boundary.

Adslytics implements Google Ads cross-domain tracking using GTM's cross-domain linker decorator, which automatically appends the session and click identifiers to outbound links pointing to the checkout domain. We configure the linker to cover all paths from the primary domain to the conversion domain, handle form posts as well as link clicks where required, and verify that GCLIDs are being passed and received correctly on the destination domain. We also ensure GA4 cross-domain measurement is configured in parallel so both platforms maintain consistent attribution. Every implementation is tested with a complete end-to-end user journey before going live.