Google says it will phase out support for third-party cookies in Chrome within two years
Google's Chrome team, advancing its web privacy effort, later this year will begin testing the “privacy sandbox” proposals it unveiled in 2019. The Chrome tests, which Google announced Tuesday …
Context & Ripple Effects
This January 2020 announcement is the opening move of a five-year arc: Google committed Chrome to dropping third-party cookies within two years while testing the Privacy Sandbox proposals it unveiled in 2019 as the replacement. The follow-on coverage shows how that two-year promise held up — Google delayed the phase-out twice, pushing it to H2 2024 citing the need for more Sandbox tests, then planned to migrate just 1% of Chrome users to Privacy Sandbox in Q1 2024 before any broader deprecation.
The endpoint matters most for reading this story: by late 2025 Google was phasing out the Privacy Sandbox technologies themselves, the very replacements announced to succeed the cookie. What began as a definitive deprecation deadline became a rolling program of tests, deferrals, and ultimately retirement of the successor stack.
First-order effects
- Advertisers and publishers built on third-party cookie targeting get a two-year clock to rework measurement and audience tools, while Chrome's own team shifts to testing the 2019 Privacy Sandbox proposals in the browser later that year.
- Google positions itself as both the party removing cross-site tracking and the designer of its replacement — an ad-funded company setting the technical standard for what replaces cookies.
Second-order effects
- Ad-tech intermediaries whose products depend on cookie-based identity must rebuild around whatever API shape Google's Sandbox tests settle on, making Chrome's test results — not open standards bodies — the de facto specification.
- Each slip in the timeline, from 2022 to 2023 to H2 2024, signals ecosystem resistance strong enough to force Google to keep the existing cookie infrastructure running longer than promised.
Third-order effects
- If the pattern holds, browser gatekeepers control the pace and design of web privacy transitions — and can abandon their own replacement stacks when they underperform, leaving the industry without either the cookie or a working substitute.
- The eventual Sandbox wind-down points toward privacy changes arriving through individual product decisions rather than coordinated industry migration, with whoever controls the dominant browser holding durable leverage over ad-targeting architecture.
The trend: Browser-controlled privacy transitions are replacing industry-wide deprecation deadlines, with the gatekeeper's own replacement technology — not the removal of cookies — proving to be the fragile part.