Google has begun taking baby steps to start the process of deprecating third-party cookies from its Chrome browser.

Johann Hofmann, senior software engineer at Google, published an in-depth series of processes that the company will take to complete its transition to Privacy Sandbox for the web.

The 1% of third-party cookie blocking will begin in “early” January 2024.

Named M120, it would be the first release that contains the technical capabilities that enable this rollout, Hofmann wrote. He also explained that this rollout will likely take a significant amount of time.

“The holiday freeze is definitely a risk to call out here. However, as mentioned in the intent, we're already operating under the assumption that some sites, despite our outreach efforts, will only find out about this once the deprecation begins,” Hofmann wrote.

To aid in the transition, Google has implemented several workarounds that are intended to ease the transition. Site owners, users and browsers can initiate them with little disruption.

“While not directly relevant to the web platform pieces, we plan to have user interface controls to give temporary exceptions per top-level site in Chrome,” Hoffmann wrote.

Google developed the phaseout plan with UK's Competition and Markets Authority with commitments the company made in February 2022 to protect consumer privacy.

The document also explains how the technology will block third-party cookies, leaving many details unspecified.

Hofmann acknowledged that it will take time for developers to replace their use of third-party tracking with new APIs or different approaches, and some developers may not be aware of this deprecation until they discover their process doesn’t work.

He lists a series of temporary workarounds for Firefox and Safari.

Phasing out third-party cookies is the goal of the Privacy Sandbox initiative, which aims to responsibly reduce cross-site tracking on the web while supporting key use cases through new technologies.

Its goal is to protect privacy while also enabling online content and services to flow freely and become accessible to everyone, Hofmann wrote. But it also is intended to provide fraud protection, critical functions across sign-ins, and gives support for advertising through new technology.

Privacy Sandbox is one of those new technologies. Anthony Katsur, CEO of IAB Tech Lab, in October called Google’s privacy plans a “radical” departure from ad targeting. He said the Google privacy plan “effectively moves the [ad] auction into the browser,” with all decisioning taking place in the browser.

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