Across browsers it has undercut the adtech model built on third-party data and pushed the industry toward first-party and privacy-safe approaches. The reality is fragmented rather than a single phase-out: Safari and Firefox block third-party cookies by default, while Chrome reversed course in April 2025, dropping its planned deprecation and keeping third-party cookies with user controls. The direction of travel is more reliable than any one browser’s decision or announced date.

In practice

Audit where your measurement and targeting still depend on third-party cookies. Those are the parts of the stack most exposed to browser restrictions, consent limits, and platform changes.