Intent to Deprecate and Remove: Topics API
Yao Xiao
Intent to Deprecate and Remove: Topics API
Contact emails
Explainer
https://github.com/patcg-individual-drafts/topics
Specification
https://patcg-individual-drafts.github.io/topics/
Summary
The Topics API is a privacy-preserving web API to enable ad-targeting based on a person’s general browsing interests, without exposing their exact browsing history.
Following Chrome's announcement that the current approach to third-party cookies will be maintained, we are now planning to deprecate and remove the Topics API (along with other Privacy Sandbox APIs).
The following API surfaces will be affected:
The JavaScript function `document.browsingTopics()` will be removed.
The `browsingtopics` attribute on <iframe> and <img> elements will be ignored.
The `browsingTopics` option in the fetch() API's RequestInit will be a no-op.
Consequently, the `Sec-Browsing-Topics` request header will no longer be sent, and the `Observe-Browsing-Topics` response header will no longer be honored.
The "browsing-topics" and "interest-cohort" permissions policy features will be removed.
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 to decrease over time (currently at 13% of page loads) as interest based advertising will remain possible in Chrome using third-party cookies. Further, other browser engines have not signaled interest in launching the API. See also the initial public proposal below.
Initial public proposal
https://privacysandbox.com/news/update-on-plans-for-privacy-sandbox-technologies/.
Possible breakage
Sites that rely on Topics API for targeting will experience utility impact.
If usage warrants, we will take steps to avoid any risk of page breakage, e.g. by temporarily retaining a stub implementation of `document.browsingTopics()` that mimics current behavior when a user has no topics to return. However, since Topics is not enabled by default for all users, sites should already be using feature detection, which makes the risks of breakage low.
Debuggability
N/A
Requires code in //chrome?
True
Estimated milestones
Deprecate in M144 and then remove in M150.
Currently, ~13% of page loads use Topics API. These are driven by a small number of third-party ad tech scripts present on a large number of sites. We will continue to monitor usage as well as provide comprehensive updates on privacysandbox.google.com with the status of the API and deprecation plans.
We will also proactively work toward reducing usage to a low level once the intent is approved, including disallowing any new enrollment sign-ups, and contacting all enrolled sites that use the Privacy Sandbox APIs to inform them about the deprecation timelines.
Link to entry on the Chrome Platform Status
https://chromestatus.com/feature/5135370673061888