One measurement setup across both domains
The same GA4 property configured on the website and the engine, with cross-domain linking so a session survives the jump.
Click IDs passed through
Campaign parameters and click IDs carried into the engine URL and, where the vendor allows it, into the reservation record itself.
A first-party tag domain
The engine on a subdomain of your own site, or at minimum the tag server, which restores a usable cookie lifetime instead of twenty-four hours.
Server-side conversions
Bookings sent from the reservation itself to GA4, Google Ads and Meta, with hashed guest details, so revenue is reported even when the browser loses the trail.
Consent carried across
Consent state passed with the guest to the engine, so measurement and law agree with each other.
Reconciliation
Monthly comparison of what the ad platforms claim against what the PMS recorded, with the gap explained rather than averaged away.
What is not fixable
A booking engine served in an un-bridged third-party iframe cannot be measured properly. Four setups in five can be fixed without changing vendor; the fifth is a decision for the owner, and we show the evidence rather than push it.
