We started the Privacy Sandbox initiative to improve web privacy for users, while also giving publishers, creators and other developers the tools they need to build thriving businesses, ensuring a safe and healthy web for all. We also know that advertising is critical for many businesses, and is a key way to support access to free content online.

Today, we’re announcing Topics, a new Privacy Sandbox proposal for interest-based advertising. Topics was informed by our learning and widespread community feedback from our earlier FLoC trials, and replaces our FLoC proposal.

With Topics, your browser determines a handful of topics, like “Fitness” or “Travel & Transportation,” that represent your top interests for that week based on your browsing history. Topics are kept for only three weeks and old topics are deleted. Topics are selected entirely on your device without involving any external servers, including Google servers. When you visit a participating site, Topics picks just three topics, one topic from each of the past three weeks, to share with the site and its advertising partners. Topics enables browsers to give you meaningful transparency and control over this data, and in Chrome, we’re building user controls that let you see the topics, remove any you don’t like or disable the feature completely.

More importantly, topics are thoughtfully curated to exclude sensitive categories, such as gender or race. Because Topics is powered by the browser, it provides you with a more recognizable way to see and control how your data is shared, compared to tracking mechanisms like third-party cookies. And, by providing websites with your topics of interest, online businesses have an option that doesn’t involve covert tracking techniques, like browser fingerprinting, in order to continue serving relevant ads.

To learn more about the details of the Topics proposal, including other design features that preserve privacy, see an overview on privacysandbox.com or read the full technical explainer. Soon, we will launch a developer trial of Topics in Chrome that includes user controls, and enables website developers and the ads industry to try it out. The final design of the user controls and the other various technical aspects of how Topics works will be decided based on your feedback and what we learn in the trial.

This is a busy time for the Privacy Sandbox. We recently worked with the U.K.’s Competition and Markets Authority (CMA) to offer revised commitments to ensure our proposals are developed in a way that works for the entire ecosystem, and later this week, we'll be sharing more details about the FLEDGE and measurement technical proposals with developers. The Privacy Sandbox is one of the most ambitious, important efforts we’ve ever undertaken, and we’re profoundly grateful for the engagement, feedback and partnership from everyone who’s participated.

Today, we’re sharing the latest on the Privacy Sandbox initiative including a timeline for Chrome’s plan to phase out support for third-party cookies. While there’s considerable progress with this initiative, it's become clear that more time is needed across the ecosystem to get this right.

The Privacy Sandbox initiative aims to create web technologies that both protect people’s privacy online and give companies and developers the tools to build thriving digital businesses to keep the web open and accessible to everyone, now, and for the future. To make this happen, we believe the web community needs to come together to develop a set of open standards to fundamentally enhance privacy on the web, giving people more transparency and greater control over how their data is used. 

In order to do this, we need to move at a responsible pace. This will allow sufficient time for public discussion on the right solutions, continued engagement with regulators, and for publishers and the advertising industry to migrate their services. This is important to avoid jeopardizing the business models of many web publishers which support freely available content. And by providing privacy-preserving technology, we as an industry can help ensure that cookies are not replaced with alternative forms of individual tracking, and discourage the rise of covert approaches like fingerprinting.

We plan to continue to work with the web community to create more private approaches to key areas, including ad measurement, delivering relevant ads and content, and fraud detection. Today, Chrome and others have offered more than 30 proposals, and four of those proposals are available in origin trials. For Chrome, specifically, our goal is to have the key technologies deployed by late 2022 for the developer community to start adopting them. Subject to our engagement with the United Kingdom’s Competition and Markets Authority (CMA) and in line with the commitments we have offered, Chrome could then phase out third-party cookies over a three month period, starting in mid-2023 and ending in late 2023. 

Each proposal goes through a rigorous, multi-phased public development process, including extensive discussion and testing periods. This is consistent with how other open APIs and web technologies get developed:

• Discussion: The technologies and their prototypes are discussed in forums like GitHub or W3C groups.
• Testing: The technologies are rigorously tested in Chrome through potentially numerous origin trials, allowing for transparency and feedback throughout. For example, we received substantial feedback from the web community during the origin trial for the first version of FLoC. We plan to conclude this origin trial in the coming weeks and incorporate input, before advancing to further ecosystem testing.
• Ready for adoption: Once the development process is complete, the successful technologies are ready to be used at scale. They will be launched in Chrome and ready for scaled use across the web.

After this public development process, and subject to our engagement with the CMA, our plan for Chrome is to phase out support for third party cookies in two stages:

• Stage 1 (Starting late-2022): Once testing is complete and APIs are launched in Chrome, we will announce the start of stage 1. During stage 1, publishers and the advertising industry will have time to migrate their services. We expect this stage to last for nine months, and we will monitor adoption and feedback carefully before moving to stage 2.
• Stage 2 (Starting mid-2023):Chrome will phase out support for third-party cookies over a three month period finishing in late 2023.

Soon we will provide a more detailed schedule on privacysandbox.com, where it will be updated regularly to provide greater clarity and ensure that developers and publishers can plan their testing and migration schedules. 

Along with progress on developing alternatives to third-party cookies, we continue to advance another key Privacy Sandbox goal to combat covert tracking like device fingerprinting. For instance, last month we published an update on our plans for User Agent string reduction, a project which aims to reduce the possibility of using this data to fingerprint and track users across the web. 

We believe that the Privacy Sandbox will provide the best privacy protections for everyone. By ensuring that the ecosystem can support their businesses without tracking individuals across the web, we can all ensure that free access to content continues. And because of the importance of this mission, we must take time to evaluate the new technologies, gather feedback and iterate to ensure they meet our goals for both privacy and performance, and give all developers time to follow the best path for privacy.