Hi API Owners, We have seen no regressions on 1% of stable (M152+) so we request permission to proceed with full removal of the API. This corresponds to step 4 of the plan Paul proposed in June. Given the low usage (<0.005%) we plan to move directly to removing these APIs on 100% of Chrome M152+.
Thanks for your consideration, --Benjamin "Russ" Hamilton On Mon, Sep 7, 2026 at 4:35 AM Anton Bershanskyi <[email protected]> wrote: > Hi Paul, > > the email form Jun 12 states that Protected Audience API implementation > would be removed in M152. When I test on Chrome 152 stable, > both navigator.joinAdInterestGroup and navigator.runAdAuction exist. Chrome > Status entry <https://chromestatus.com/feature/6552486106234880> states > that removal is planned for M153. Did the removal milestone get postponed > by a milestone from 152 to 153? > > Sincerely, > Anton. > > On Saturday, July 18, 2026 at 11:38:05 PM UTC+3 Garrett Johnson wrote: > >> Paul, >> Thanks for taking the time to respond and explain. This is a useful for >> me to refer to when explaining this to the reader. >> Warm regards, >> >> Garrett >> >> On Thursday, 16 July 2026 at 13:48:55 UTC-4 Paul Jensen wrote: >> >>> Garrett, >>> >>> >>> When we marked the Protected Audience API as deprecated, in >>> crrev.com/1545185, this included more of the API surface into the >>> “Fledge” Blink use counter. You can see we added “DeprecateAs=Fledge” to a >>> lot of the APIs in navigator_auction.idl in that change. It wasn’t >>> actually an increase in API usage, it was just a change in measurement. >>> You can see there were no corresponding spikes in particular API usage: >>> https://chromestatus.com/metrics/feature/timeline/popularity/3855 >>> https://chromestatus.com/metrics/feature/timeline/popularity/3857 >>> >>> On Tuesday, July 14, 2026 at 10:50:58 AM UTC-4 Garrett Johnson wrote: >>> >>>> I'm a researcher in this space who has ongoing research >>>> <https://ssrn.com/abstract=4983927> measuring the adoption and use of >>>> Privacy Sandbox tools. >>>> >>>> I'm hoping that someone in this chain could resolve a mystery for me >>>> about the Fledge usage metrics in the Chrome Platform Status data here >>>> <https://chromestatus.com/metrics/feature/timeline/popularity/4188>. >>>> Basically, this approaches 0% of page loads in Q4 2025 as you would expect >>>> given its retirement. However, usage spikes to its highest ever usage in Q1 >>>> 2026 (peaking at 7.7%). This is unexpected: as mentioned above, auctions & >>>> interest group activity has gone to almost 0 in the Chrome Platform Status >>>> data (and my own). My guess is that some deprecation flag is being counted >>>> here, but I really don't know. Other researchers >>>> <https://arxiv.org/abs/2606.26390> found a similar spike in the HTTP >>>> Archive data. >>>> >>>> I'd really appreciate your input here in setting the record straight on >>>> whether PA API's post-retirement was in fact a mirage. Big bonus points if >>>> you can explain why this happened. >>>> >>>> Sincerely, >>>> >>>> Garrett Johnson >>>> Associate Professor >>>> Questrom School of Business >>>> Boston University >>>> https://garjoh.com >>>> >>>> On Wednesday, 1 July 2026 at 14:25:39 UTC-4 Daniel Bratell wrote: >>>> >>>>> LGTM3 for steps 2 and 3. >>>>> >>>>> /Daniel >>>>> On 2026-06-25 19:05, Chris Harrelson wrote: >>>>> >>>> LGTM2 >>>>> >>>>> On Thu, Jun 25, 2026 at 9:56 AM Yoav Weiss (@Shopify) < >>>>> [email protected]> wrote: >>>>> >>>>> LGTM1 >>>>>> >>>>>> On Fri, Jun 12, 2026 at 2:32 AM Paul Jensen <[email protected]> >>>>>> wrote: >>>>>> >>>>> Hi API Owners, Protected Audience API was deprecated in Chrome-144 >>>>>>> with a plan to remove it in Chrome-150. Currently the usage is 1.1% >>>>>>> of page loads. >>>>>>> <https://chromestatus.com/metrics/feature/timeline/popularity/4188>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, >>>>>>> >>>>>>> Paul >>>>>>> >>>>>>> On Wed, Nov 12, 2025 at 11:30 AM Vladimir Levin <[email protected]> >>>>>>> wrote: >>>>>>> >>>>>> LGTM2 >>>>>>>> >>>>>>>> On Wednesday, November 12, 2025 at 11:30:32 AM UTC-5 Chris >>>>>>>> Harrelson wrote: >>>>>>>> >>>>>>> LGTM1 >>>>>>>>> >>>>>>>>> On Fri, Nov 7, 2025 at 11:04 AM Paul Jensen <[email protected]> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>> Intent to Deprecate and Remove: Protected Audience >>>>>>>>>> Contact emails >>>>>>>>>> >>>>>>>>> [email protected] >>>>>>>>>> >>>>>>>>> >>>>>>>>>> Explainer >>>>>>>>>> >>>>>>>>>> https://github.com/WICG/turtledove/blob/main/FLEDGE.md >>>>>>>>>> >>>>>>>>>> Specification >>>>>>>>>> >>>>>>>>>> https://wicg.github.io/turtledove/ >>>>>>>>>> >>>>>>>>>> Summary The Protected Audience API provides a method of >>>>>>>>>> interest-group advertising without third-party cookies or user >>>>>>>>>> tracking >>>>>>>>>> across sites. >>>>>>>>>> >>>>>>>>>> Following Chrome's announcement >>>>>>>>>> <https://privacysandbox.com/news/privacy-sandbox-next-steps/> >>>>>>>>>> that the current approach to third-party cookies will be maintained, >>>>>>>>>> we are >>>>>>>>>> now planning to deprecate and remove >>>>>>>>>> <https://privacysandbox.com/news/update-on-plans-for-privacy-sandbox-technologies/> >>>>>>>>>> the Protected Audience API (along with certain other Privacy Sandbox >>>>>>>>>> APIs, >>>>>>>>>> as outlined on the Privacy Sandbox feature status page >>>>>>>>>> <https://privacysandbox.google.com/overview/status>). >>>>>>>>>> >>>>>>>>>> Blink component >>>>>>>>>> >>>>>>>>>> Blink>InterestGroups >>>>>>>>>> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EInterestGroups%22> >>>>>>>>>> >>>>>>>>>> Web Feature ID >>>>>>>>>> >>>>>>>>>> None >>>>>>>>>> >>>>>>>>>> Motivation >>>>>>>>>> >>>>>>>>>> Chrome has announced that the current approach to third-party >>>>>>>>>> cookies will be maintained. Since that announcement there has >>>>>>>>>> been virtually no interest in the Protected Audience API. Use of >>>>>>>>>> the joinAdInterestGroup() API >>>>>>>>>> <https://chromestatus.com/metrics/feature/timeline/popularity/3855> >>>>>>>>>> has decreased by almost 100x and use of the runAdAuction() API >>>>>>>>>> <https://chromestatus.com/metrics/feature/timeline/popularity/3857> >>>>>>>>>> has decreased by more than 10x. Of the auctions occurring today, >>>>>>>>>> virtually >>>>>>>>>> none of them have winners (determined by looking at the “Success” >>>>>>>>>> bucket >>>>>>>>>> count of the Ads.InterestGroup.Auction.Result UMA), implying that >>>>>>>>>> they are >>>>>>>>>> not providing useful benefit to the pages initiating them. >>>>>>>>>> >>>>>>>>>> Initial public proposal >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> https://privacysandbox.com/news/update-on-plans-for-privacy-sandbox-technologies/ >>>>>>>>>> . >>>>>>>>>> >>>>>>>>>> Developer-facing impact >>>>>>>>>> >>>>>>>>>> Given that virtually none of the Protected Audience auctions >>>>>>>>>> occurring today have winners, we estimate the lost utility from this >>>>>>>>>> removal to be negligible. >>>>>>>>>> >>>>>>>>>> User-facing risks >>>>>>>>>> >>>>>>>>>> The user-facing risks are small. While removing the JavaScript >>>>>>>>>> API could cause pages to break, the impact should be limited to >>>>>>>>>> sites that >>>>>>>>>> don't employ standard defensive coding or feature detection, which >>>>>>>>>> should >>>>>>>>>> be rare since not all browsers implement the API. >>>>>>>>>> >>>>>>>>>> If usage warrants, we will take steps to avoid any risk of page >>>>>>>>>> breakage, e.g. by temporarily retaining a stub implementation of >>>>>>>>>> Navigator >>>>>>>>>> APIs joinAdInterestGroup(), runAdAuction(), leaveAdInterestGroup(), >>>>>>>>>> clearOriginJoinedAdInterestGroups(), getInterestGroupAdAuctionData(), >>>>>>>>>> canLoadAdAuctionFencedFrame(), createAuctionNonce(), >>>>>>>>>> updateAdInterestGroups(), protectedAudience.queryFeatureSupport(), >>>>>>>>>> deprecatedReplaceInURN(), deprecatedURNtoURL(), and >>>>>>>>>> adAuctionComponents() >>>>>>>>>> that mimic current behavior when a user has disabled Protected >>>>>>>>>> Audience. >>>>>>>>>> >>>>>>>>>> Estimated milestones >>>>>>>>>> >>>>>>>>>> Planning to deprecate in M144 and remove in M150. >>>>>>>>>> >>>>>>>>>> Currently 0.22% >>>>>>>>>> <https://chromestatus.com/metrics/feature/timeline/popularity/4188> >>>>>>>>>> of page loads use the Protected Audience 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 >>>>>>>>>> <https://privacysandbox.google.com/overview/status>. >>>>>>>>>> >>>>>>>>>> We will also 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. >>>>>>>>>> >>>>>>>>>> Protected Audience features that were never launched beyond 20% >>>>>>>>>> Stable (TextEncoder support >>>>>>>>>> <https://github.com/WICG/turtledove/issues/961#issuecomment-2793763963>, >>>>>>>>>> Creative scanning via BYOS/V1 trusted scoring signals >>>>>>>>>> <https://groups.google.com/a/chromium.org/g/blink-dev/c/EXfp34Qb1oc/m/oaiY6MENBwAJ>, >>>>>>>>>> Selectable Reporting IDs >>>>>>>>>> <https://groups.google.com/a/chromium.org/g/blink-dev/c/1cWqBPHngd0/m/gSYeR_dPAAAJ>) >>>>>>>>>> will be ramped down by the end of 2025. >>>>>>>>>> >>>>>>>>>> Protected Audience services, Bidding and Auction services >>>>>>>>>> <https://groups.google.com/a/chromium.org/g/blink-dev/c/CyXJz3xOEcc/m/1snkv2KhAwAJ> >>>>>>>>>> and Trusted Key Value service >>>>>>>>>> <https://groups.google.com/a/chromium.org/g/blink-dev/c/fH8u7ZTNZg8/m/oo0WVw7SAQAJ>, >>>>>>>>>> will not onboard new clients once deprecation is approved. We will >>>>>>>>>> work >>>>>>>>>> with onboarded clients and plan to turn down the services by the end >>>>>>>>>> of >>>>>>>>>> year as usage is negligible today. This will have no user-facing or >>>>>>>>>> web-compat impact. >>>>>>>>>> >>>>>>>>>> Link to entry on the Chrome Platform Status >>>>>>>>>> >>>>>>>>>> https://chromestatus.com/feature/6552486106234880 >>>>>>>>>> >>>>>>>>> -- >>>>>>>>>> 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/CABQTWrnevtY14OMos%2BuDgzXtFwQJ5vzY3hEMmyRFQBKDHBz-9A%40mail.gmail.com >>>>>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABQTWrnevtY14OMos%2BuDgzXtFwQJ5vzY3hEMmyRFQBKDHBz-9A%40mail.gmail.com?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/CABQTWrmRRxZO%3D%2BCmt-hfkBBjeR8j4umTer8krMvmAyiVP_1HXw%40mail.gmail.com >>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABQTWrmRRxZO%3D%2BCmt-hfkBBjeR8j4umTer8krMvmAyiVP_1HXw%40mail.gmail.com?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/CAOmohS%2BRQAUtSUZw%3D4TsVgNOxcuR5aeQhym2CZO-_WmzUnndLQ%40mail.gmail.com >>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOmohS%2BRQAUtSUZw%3D4TsVgNOxcuR5aeQhym2CZO-_WmzUnndLQ%40mail.gmail.com?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%2Bw94fqnFNWSUWQSm7crPrzuLbO6Cz5p9Rg0BLEJsU%3DHPPg%40mail.gmail.com >>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOMQ%2Bw94fqnFNWSUWQSm7crPrzuLbO6Cz5p9Rg0BLEJsU%3DHPPg%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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