Hi API Owners,
The Topics API was deprecated in Chrome-144 with a plan to remove it in Chrome-150. Currently the usage is 4.9% of page loads. <https://chromestatus.com/metrics/feature/timeline/popularity/5102>We are proposing the following as next steps for removal and associated timelines: 1. M150: Remove all Ads API-related entries from Chrome settings and UI surfaces (e.g., chrome://settings/adPrivacy) via field trial. After this point, all API invocations for field-trial enabled browsers will always reject. Since the API can already be disabled for one of many reasons, scripts must already handle such rejections (or they’re already significantly broken). 2. M152: Permanently remove the underlying implementation code for the API, and replace it with a lightweight stub API. The stub will remain removable via field trial. 3. M152 Canary/Beta: Begin a controlled rollout of the stub API removal via a field trial. 4. M152 Stable: Assuming there are no regressions or breakage after reaching 1% stable, we will request additional approval for full removal at this stage. At this time, we are seeking LGTMs for steps #2 and #3. Thanks, Yao On Wednesday, November 12, 2025 at 11:36:22 AM UTC-5 Daniel Bratell wrote: > LGTM3 according to Vlad's plan. > > /Daniel > On 2025-11-12 17:19, Chris Harrelson wrote: > > LGTM2 with the same conditions Vlad mentioned. > > On Wed, Nov 12, 2025 at 8:16 AM Vladimir Levin <[email protected]> > wrote: > >> LGTM1 to deprecate. The plan to keep deprecation for 6 milestones also >> sounds good. Please come back after to this thread at a time when you think >> the removal can proceed. Since the amount of page loads is extremely high, >> we would like to reserve the right to pause the removal if this amount of >> page loads does not decrease substantially. >> >> On Friday, November 7, 2025 at 1:12:36 PM UTC-5 Yao Xiao wrote: >> >>> Intent to Deprecate and Remove: Topics API >>> >>> Contact emails >>> >>> [email protected] >>> >>> 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 >>> >>> Blink>TopicsAPI >>> <https://issues.chromium.org/u/1/issues?q=customfield1222907:%22Blink%3ETopicsAPI%22> >>> >>> 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% >>> <https://chromestatus.com/metrics/feature/timeline/popularity/5102> 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% >>> <https://chromestatus.com/metrics/feature/timeline/popularity/5102> 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 <http://goo.gle/ps-status> 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 >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "blink-dev" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion visit >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/c97119d8-b351-4e2d-b106-c7ea1e4f60ccn%40chromium.org >> >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/c97119d8-b351-4e2d-b106-c7ea1e4f60ccn%40chromium.org?utm_medium=email&utm_source=footer> >> . >> > -- > You received this message because you are subscribed to the Google Groups > "blink-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > > To view this discussion visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOMQ%2Bw_L%2BDZoLM8ApVQQarUWAoVsQ9tueQHjoxeGgYsz8pmSDA%40mail.gmail.com > > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOMQ%2Bw_L%2BDZoLM8ApVQQarUWAoVsQ9tueQHjoxeGgYsz8pmSDA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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