Full Answer

The gclid disappearance on Safari is arguably the single most expensive browser-side attribution problem for WooCommerce stores running Google Ads, and the mechanism is worth understanding in detail.

Google Click Identifier is the parameter Google Ads appends to every ad click URL. When a user lands on your store, Google's tracking script reads the gclid from the URL and stores it in a first-party cookie. When that user later completes a purchase, the conversion tag reads the cookie and reports the purchase back to Google Ads, closing the attribution loop.

Safari ITP breaks this loop by classifying google.com as a known tracking domain. When a user arrives via a Google Ads click — identified by the gclid parameter in the URL — Safari recognises this as link decoration from a classified domain and applies the 24-hour cookie restriction. The gclid cookie set by JavaScript expires after one day, not the 30 or 90 days that Google Ads attribution models assume.

The practical consequences are severe. A customer who clicks your Google Ads campaign on Monday afternoon and purchases on Wednesday morning — a perfectly normal 36-hour consideration period — generates zero attributed revenue in Google Ads if they used Safari. This distorts Smart Bidding algorithms, which optimise based on reported conversion data. Enhanced Conversions and server-side measurement both address this gap by linking conversions through first-party data matching rather than browser cookies.