Why we build cookieless attribution

The usual argument for cookieless tracking is that the cookie is dying. It isn’t. Google abandoned its third-party cookie deprecation in April 2025 and retired most of the Privacy Sandbox in October. Anyone still selling you the death of the cookie stopped reading the news two years ago.

The real problem is narrower, older, and easier to verify.

What Safari does to an affiliate link

Most affiliate tools set a first-party cookie from JavaScript on the merchant’s own domain. In February 2019, WebKit capped those at seven days. Two months later it added a sharper rule: when a visitor arrives from a cross-site navigation and the URL carries a query string, the cap drops to 24 hours.

That is the exact shape of an affiliate link. A partner’s link is a cross-site navigation carrying a query string, so on Safari the tracking cookie behind it expires in a day. For a B2B SaaS product with a two-week evaluation cycle, the partner who sent the customer is gone from the record long before the customer pays.

WebKit’s own wording is worth keeping: only cookies created through document.cookie are affected. Cookies set by a server are not.

Where we put the attribution instead

Selgeo records the referral on our server the moment the click lands. The click ID lives in sessionStorage and is matched to the Stripe payment server-side, so nothing depends on a cookie surviving two weeks in a browser that has decided it shouldn’t.

That is the whole idea: the record of who sent the customer sits next to the payment that customer made, and stays there.