Topics

Topics is a proposal in the Privacy Sandbox designed to preserve privacy while showing relevant content and ads. The browser will infer a handful of recognizable, interest-based categories based on recent browsing history to help sites serve relevant ads. With Topics, the specific sites you’ve visited are no longer shared across the web, like they might have been with third-party cookies.

How it works

There are two main parts to Topics. First, the API labels each website from a set of recognizable, high-level topics. For example, the browser would match a sports website with the topic "Sports". Then, the browser collects a few of the most frequent topics associated with the websites you’ve visited. These topics are then shared (one new topic per week) with the sites you visit to help advertisers show you more relevant ads, without needing to know the specific sites you’ve visited.

The browser will use a limited set of topics selected from a human-curated, publicly visible list. The updated list contains around 469 topics - we limit the taxonomy’s size to reduce the risk of fingerprinting. Additionally, Chrome aims to maintain a topics list that does not include sensitive categories (i.e. race, sexual orientation, religion, etc.).

You will be able to see the topics and remove any you don’t like, or disable them completely in Chrome Settings.

Frequently Asked Questions

How is Topics related to FLoC?

FLoC was Chrome’s initial privacy-preserving proposal to allow companies to show relevant ads to people based on their web browsing activity, without revealing specific sites they visited to any external parties including Google. Chrome experimented with FLoC in 2021 and received valuable feedback from regulators, privacy advocates, developers and industry. The new Topics API proposal addresses the same general use case as FLoC, but takes a different approach intended to address the feedback received for FLoC. Chrome intends to experiment with the Topics API and is no longer developing FLoC.

When will Topics be rolled out in Chrome?

In May 2023, we announced our intent to make Topics, and other Privacy Sandbox APIs, generally available in Chrome Stable 115. You can view the latest status here.

Can I control the topics in my browser, or opt-out completely?

In Chrome settings, you will be able to find which topics have been generated based on your recent browsing history. You will be able to block specific topics or opt out of the Privacy Sandbox technologies completely.

Can I see the full list of available topics?

Chrome proposed an initial list of topics publicly in January 2022. Based on ecosystem feedback, Chrome announced an updated list of topics in June 2023. Chrome expects the taxonomy to evolve over time, and for governance of the taxonomy to eventually transition to an external party representing stakeholders from across the industry. We encourage the ecosystem to review the latest taxonomy and provide feedback on the changes.

Can Topics reveal a person’s membership in a sensitive group?

As Topics uses a recognizable and human-curated list of topics to help infer what ads you will see, Chrome can and will take steps to avoid topics that might be sensitive (i.e. race, sexual orientation, religion, etc.). However, it is still possible that websites calling the API may combine or correlate topics with other signals to infer sensitive information, outside of intended use. Chrome will continue to investigate methods for reducing this risk.

What data does the browser use to determine my topics for each week?

First, Chrome determines the topics associated with websites. For example, a yoga website might be classified as being related to "Fitness". These topics are assigned to the websites themselves, not you. Then, Chrome keeps a handful of your most frequently visited topics in a given week, and participating sites show you ads based on these topics.

The calculation of the most frequent topics occurs entirely within the browser, without sharing data with external servers. The resulting topics may be sent to servers in an anonymous way for sensitivity and abuse analysis.

Can websites opt-out of being included in topics’ generation?

Yes. Only sites that are using Topics or have at least one embedded service that uses the Topics API, will be included in topics generation. Sites can also specifically opt-out using Permission Policy, an existing browser mechanism that is used to control features like camera access.

If a website had opted out of FLoC, the Topics API will respect that decision.

Where can I learn more?

The Privacy Sandbox Learning Hub is a good place to start. You can also review " What is the Topics API?" on developer.chrome.com.