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The next stages of Privacy Sandbox: General availability and supporting scaled testing


The Privacy Sandbox is an ecosystem-wide initiative to ensure an open and thriving web, by improving user privacy and giving businesses the tools they need to succeed online. Over the past three years, we’ve collaborated with the web ecosystem to develop new, privacy-preserving technologies that don't rely on cross-site tracking identifiers or covert techniques like fingerprinting. Last year, we expanded testing so that developers can evaluate these new technologies as they incorporate them into their solutions.

Today, we’re sharing an update on the next stage of the Privacy Sandbox for the web, as we work towards deprecating third-party cookies in Chrome in the second half of 2024.

General availability of the Privacy Sandbox APIs

Starting with the July Chrome release, and over the following weeks, we’ll make the Privacy Sandbox relevance and measurement APIs available to all Chrome users.

With this milestone, developers can utilize these APIs to conduct scaled, live-traffic testing, as they prepare to operate without third-party cookies. Prior to third-party cookie deprecation, we don’t plan to make any significant changes to the API interfaces. Companies who haven’t already done so should evaluate integrating these APIs into their products as they plan their transition to more private solutions.

Supporting scaled testing with one percent third-party cookie deprecation in Q1 2024

To get ready for the web without third-party cookies, it’s important that the ecosystem prepare in advance, including evaluating solutions which incorporate the Privacy Sandbox APIs. To support this, we will take the following additional steps over the coming quarters.

In Q1 of 2024, we plan to deprecate third-party cookies for one percent of Chrome users. This will support developers in conducting real world experiments that assess the readiness and effectiveness of their products without third-party cookies. In addition, in Q4 of 2023, we will introduce the ability for developers to simulate Chrome third-party cookie deprecation for a configurable percentage of their users. This will enable developer-controlled testing that can benefit from higher levels of third party cookie-less traffic.

This plan has been developed in consultation with the UK’s Competition and Markets Authority (CMA), in accordance with our Commitments and public timeline. We will continue to address comments made by the CMA, as we prepare for third-party cookie deprecation beyond one percent of Chrome users once the CMA has completed its assessment.

Working with the industry

We're encouraged by the ecosystem engagement on Privacy Sandbox and will continue to work with the industry on how these technologies can support the transition to a more private web.

"As a leader in testing Protected Audience (formerly FLEDGE), OpenX appreciates Google’s continued commitment to working with the ecosystem to enhance consumer privacy. Increased traffic and cookieless testing options will significantly help the evaluation of the Privacy Sandbox solutions, such as Protected Audience, and the preparedness for Chrome’s third-party cookie deprecation."
Paul Ryan
"At RTB House, we value the Chrome team's consideration of tester feedback, including the necessity to test technologies on traffic that doesn't rely on 3rd party cookie data. We are ready to test on increased volume, plan to conduct scaled developer experiments and look forward to collaborating across the programmatic supply chain on them. We believe that the test results will enable us to further refine our solutions based on the privacy-preserving APIs so that they can compete on an equal footing with legacy technologies that rely on 3rd party cookies."
Lukasz Wlodarczyk
VP of Programmatic Ecosystem Growth & Innovation
RTB House

Echoing comments from the CMA’s Q1 Report, we expect a wide range of testing methodologies based on different testing goals — from single-company tests, to broader coordinated tests across multiple organizations. We also encourage developers to adopt and test the Privacy Sandbox APIs as part of end-to-end solutions.

Please visit the Chrome developer blog for more information on the rollout of the Privacy Sandbox APIs. We’ll provide more details over the coming months, including additional guidance on testing metrics and methodologies.

We look forward to continuing to collaborate with participants across the industry, as we reach the final stages of our journey to deprecate third-party cookies in Chrome, and improve privacy across the web for everyone.