What is URL passthrough in Google Consent Mode?

URL passthrough allows Google tags to pass certain measurement information through URL parameters when cookie-based measurement is unavailable, including situations where relevant cookie storage consent is denied. This can help preserve information needed for advertising and analytics measurement without relying on those cookies.

URL passthrough requires consent-aware Google tags and must be enabled in the Google tag configuration. Depending on the measurement setup, parameters can be passed between pages or domains to preserve measurement information.

You may see parameters such as gclid or _gl added to URLs:

• gclid can carry a Google Ads click identifier.

• _gl is used by Google tag linker functionality to pass measurement information, including for cross-domain measurement.

Redirects and other URL handling should preserve these parameters when they are required for measurement. Website configurations should also ensure that URL parameters do not expose or transmit inappropriate personal or sensitive information.

URL passthrough does not grant consent, override a visitor’s refusal, or replace a consent banner. It is a measurement mechanism that works alongside consent settings.

See Google’s URL passthrough guidance.