Privacy-related compliance FAQs

# Privacy-related compliance FAQs for Privacy Sandbox Relevance and Measurement APIs

Privacy Sandbox relevance and measurement APIs and updated user controls are now generally available in Chrome. Ecosystem participants have asked about Chrome's approach to privacy-related compliance with Privacy Sandbox as well as their own responsibilities. While we cannot provide legal advice, we can share our responses to frequently asked questions and provide information about the APIs that can help those responsible for privacy-related compliance decisions.

# Questions and answers

Do sites and other Privacy Sandbox relevance and measurement API callers have ePrivacy obligations?

Laws like ePrivacy require consent to store or access data on and from a user's browser unless strictly necessary and do not differentiate between legacy technologies such as third-party cookies, and emerging Privacy Enhancing Technologies (PET) such as the Privacy Sandbox APIs.

Use of each of the Privacy Sandbox APIs involves accessing data that is stored on the user's device.

For reference, companies can see how Google's own ads services, which operate independently from Chrome, are incorporating Privacy Sandbox technologies as part of their EU User Consent Policies. As the landscape evolves, we are hopeful that the privacy benefits of PETs may be reflected in user consent regulations in the future. We encourage companies to monitor privacy regulations and DPA guidance, and assess their own obligations.

Can users withdraw consent or otherwise control Privacy Sandbox relevance and measurement APIs?

Yes. Users can access chrome://settings/adPrivacy, which provides individual, granular controls for turning off Privacy Sandbox APIs, blocking individual topics and specific sites from setting Interest Groups. Users can delete ad-measurement data by deleting browsing data.

Sites will need to determine what choices they offer to users, how those preferences are stored, how a user's preference is signaled to the site's ad-tech vendors who may call the Privacy Sandbox APIs, and how those vendors are held accountable. Sites and their vendors will need to decide what a user's choice means in terms of whether and how a given Privacy Sandbox API is used.

Some opt-out based, self-regulatory programs such as AdChoices rely on third-party cookies. We encourage you to ask those programs how they are preparing for third-party cookie deprecation.

Can user choices related to Privacy Sandbox be persisted across sites?

Users can access chrome://settings/adPrivacy, which provides controls for turning off Privacy Sandbox APIs altogether or blocking individual topics. Users can delete ad-measurement data by deleting browsing data.

Sites will need to determine whether they take responsibility for extending user choices expressed on their own sites to the rest of the web. Some opt-out based, self-regulatory programs such as AdChoices are meant to offer users choices about how ad tech companies process user data across sites (such as Interest-based Advertising). Traditionally those programs are specific to ad tech companies who choose to participate, and not to sites. We encourage you to ask those programs how they are preparing for third-party cookie deprecation.

Can users delete data related to Privacy Sandbox relevance and measurement APIs?

Users can access chrome://settings/adPrivacy, which provides individual, granular controls for turning off Privacy Sandbox APIs, blocking individual topics and specific sites from setting Interest Groups. Users can delete ad-measurement data by deleting browsing data. Additionally, Chrome will automatically delete users' topics of interest, Interest Groups and reporting events after a set period of time.

For sites and other Privacy Sandbox relevance and measurement API callers, the following technical functions are available:

• For Protected Audience, a site or its ad tech that can add Interest Groups from this site can also call the leaveAdInterestGroup function.
• For Shared Storage, a site or its ad tech can call the delete method on a key or the clear method to clear all keys.
• For the Attribution Reporting API, a site or its ad tech can use the Clear-Site-Data header.

Sites and other API callers will need to determine if their current mechanisms for deletion rights are suitable if and when they have chosen to store data retrieved from Privacy Sandbox APIs or data related to calling the APIs.

How is Privacy Sandbox approaching privacy-related compliance in Chrome?

In the case of Topics, this is a new experience for Chrome users and Chrome wanted to provide a separate moment for users to learn and choose what's best for them. Topics marks a new way for Chrome to enable relevant experiences based on a user's browsing history, and Chrome has taken the decision to ask for consent from users in the UK/EEA and Switzerland before enabling the API.

The Protected Audience and measurement APIs represent more private versions of existing processing behaviors both within the browser and in protected, trusted environments. Overall, all users will have robust controls, and can opt out of the Privacy Sandbox experience at any point.

You can learn more about Privacy Sandbox ad controls in our Help Center.

# More API information

Learn more about the Privacy Sandbox relevance and measurement APIs:

• Topics: Generate signals for interest-based advertising without third-party cookies or other user identifiers that track individuals across sites.
• Protected Audience: Select ads to serve remarketing and custom audience use cases, designed to mitigate third-party tracking across sites.
• Attribution Reporting: Correlate ad clicks or ad views with conversions. Ad techs can generate event-level or summary reports.
• Private Aggregation: Generate aggregate data reports using data from Protected Audience and cross-site data from Shared Storage.
• Shared Storage: Allow unlimited, cross-site storage write access with privacy-preserving read access.
• Fenced Frames: Securely embed content onto a page without sharing cross-site data.