Intent to Deprecate and Remove: Private Aggregation API
Alex Turner
Contact emails
Explainer
https://github.com/patcg-individual-drafts/private-aggregation-api
Specification
https://patcg-individual-drafts.github.io/private-aggregation-api
Summary
The Private Aggregation API is a generic mechanism for measuring aggregate, cross-site data in a privacy preserving manner. It was originally designed for a future without third-party cookies.
Following Chrome's announcement that the current approach to third-party cookies will be maintained, we are now planning to deprecate and remove the Private Aggregation API (along with certain other Privacy Sandbox APIs, as outlined on the Privacy Sandbox feature status page). This API is only exposed via the Shared Storage and Protected Audience APIs, which are also planned to be deprecated and removed. So, no additional work will be required for Private Aggregation.
Blink component
Web Feature ID
None
Motivation
Chrome has announced that the current approach to third-party cookies will be maintained. Given this, we expect adoption of the Private Aggregation API to decrease over time as cross-site measurement will remain possible in Chrome using third-party cookies. Further, other browser engines have not signaled interest in launching the API. Removing this (and certain other Privacy Sandbox APIs) will help focus efforts on the proposed interoperable Attribution standard.
Possible breakage
Sites that rely on Private Aggregation reports for cross-site measurement and do not migrate to alternative solutions will experience a disruption on the removal of the API.
No specific JavaScript API changes are required to remove Private Aggregation as the API is only exposed within Protected Audience and Shared Storage contexts. So, Private Aggregation’s functionality is planned to be transitively removed by the removal of those two APIs.
If usage warrants, the Protected Audience and Shared Storage APIs may be temporarily retained with stub/no-op implementations of their calls to avoid any risk of page breakage. In that case, the isolated contexts where Private Aggregation is exposed would still no longer be created and there would be no need to retain a stub implementation of Private Aggregation.
User-facing risks
Please see Protected Audience and Shared Storage’s Intents to Deprecate and Remove.
Debuggability
N/A
Requires code in //chrome?
False
Estimated milestones
Deprecate in M144 and then remove in M150.
There will be one aspect of the API that will end sooner. Server-side summary report computation will no longer operate by late December 2025. We have already communicated to the users of that service of these plans. Such users can use debug reports instead until the removal of the API surface as a whole. Since this impacts post-facto server-side operations, it will not incur any user-facing breakage.
Currently ~3% of page loads use the Private Aggregation API. While this usage is quite high for a deprecation and removal, it is driven by a small number of third-party ad tech scripts present on a large number of sites. We will continue to monitor usage in addition to providing comprehensive updates on privacysandbox.google.com with the status of the API and deprecation plans.
We will proactively work toward reducing usage to low levels once this intent is approved, including disallowing any new enrollment sign-ups, and contacting enrolled sites to inform them about the deprecation timelines.
Please see Protected Audience and Shared Storage’s Intents to Deprecate and Remove for plans in case usage is still too high to fully remove those APIs at M150 due to user-facing breakage concerns.
Link to entry on the Chrome Platform Status
https://chromestatus.com/feature/4683382919397376?gate=6554931293192192
This intent message was generated by Chrome Platform Status.