Full Answer
Safari's Intelligent Tracking Prevention classifies cookies set by cross-site tracking scripts as third-party cookies and expires them after 7 days. Any customer who returns after a week is treated as a new visitor with no attribution history—breaking multi-touch attribution and ad channel performance data.
Server-side tracking bypasses this mechanism entirely. Events fire from your server, running on your own subdomain, directly to the platform API. No browser-side cookie is required. Whether the customer's Safari cookie is 2 days old or expired 3 weeks ago, the purchase event still reaches Google Ads, Facebook, and TikTok with full conversion data.
For stores with longer purchase consideration periods—higher-ticket products, B2B services, comparison shoppers—the ITP attribution gap is significant. Server-side tracking closes it.