This is great, good luck with the deprecation! This feature is exposed on Android WebView as well, including an API for Android apps, do you expect to deprecate those in line with this effort?
Thanks, Peter On Wed, Nov 12, 2025 at 11:05 PM Mike Taylor <[email protected]> wrote: > LGTM3 to deprecate. > On 11/13/25 1:44 a.m., Daniel Bratell wrote: > > LGTM2 for deprecation (not for the actual removal) > > /Daniel > On 2025-11-12 17:28, Vladimir Levin wrote: > > LGTM1 to deprecate. This feature removal sounds riskier than other related > features, especially coupled with 20% page loads. So although the plan to > monitor for 6 milestones sounds good, this approval does *not* extend to > removal. Please come back to this thread closer to the proposed removal to > see if the usage had dropped substantially. > > On Sunday, November 9, 2025 at 7:47:04 PM UTC-5 Mike Taylor wrote: > >> Could you please request Debuggability and Testing bits in your >> chromestatus entry >> On 11/8/25 3:35 a.m., Nan Lin wrote: >> >> Intent to Deprecate and Remove: Attribution Reporting API >> >> Contact emails >> >> [email protected], [email protected], [email protected] >> >> Explainer >> >> https://github.com/WICG/attribution-reporting-api >> >> Specification >> >> https://wicg.github.io/attribution-reporting-api/ >> >> Summary >> >> The Attribution Reporting API (ARA) is a privacy-preserving web API >> designed to measure ad conversions 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 Attribution Reporting 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 >> >> Internals > AttributionReporting >> <https://bugs.chromium.org/p/chromium/issues/list?q=component:Internals%3EAttributionReporting> >> >> Web Feature ID >> >> None >> >> Motivation >> >> Chrome has announced >> <https://privacysandbox.com/news/update-on-plans-for-privacy-sandbox-technologies/> >> that the current approach to third-party cookies will be maintained. Given >> this, we expect adoption of the Attribution Reporting API to decrease over >> time, as cross-site measurement will remain possible in Chrome using >> third-party cookies. Further, although Microsoft Edge integrates with the >> Attribution Reporting API, most other browser engines have not signaled >> interest in launching the API. Removing this (and certain other Privacy >> Sandbox APIs <https://privacysandbox.google.com/overview/status>) will >> help focus efforts on the proposed interoperable Attribution >> <https://github.com/w3c/attribution> standard. >> >> Developer-facing impact >> >> Sites that are using the Attribution Reporting API for conversion >> measurement and do not migrate to alternative solutions may experience a >> disruption in conversion measurement on eventual removal of the API code >> from Chrome. >> >> >> - >> >> Conversion measurement disruption: All ad conversion events relying >> on the deprecated API will fail to register or report. Sites using this >> API >> as their primary or supplementary method for ad measurement will lose >> visibility into campaign performance metrics derived from this technology. >> - >> >> Public API surface: The following outlines the consequences of >> deprecating and removing the Attribution Reporting API for each of the >> interfaces defined here >> <https://wicg.github.io/attribution-reporting-api/#idl-index>. >> - >> >> Potentially user-breaking >> - >> >> XMLHttpRequest.setAttributionReporting(): Calling >> setAttributionReporting() on an XMLHttpRequest object will >> throw an exception because the method will no longer exist. This is >> a >> breaking change for any site that calls this method. Given that this >> feature is not implemented in other browsers, it is likely that >> sites are >> already using feature detection to check the method’s existence >> before >> calling it, which would prevent breakage. We will start to track >> the usage >> of this method. >> - >> >> Non user-breaking >> - >> >> HTMLAttributionSrcElementUtils and the attributionsrc >> attribute: The attributionsrc attribute on <a>, <area>, <img>, >> and <script> elements will be ignored. Any values assigned to this >> attribute will have no effect, and the browser will no longer >> initiate >> background requests to register attribution sources/triggers. >> Additionally >> we will no longer process trigger headers on legacy subresource >> requests >> that lack the opt-in (either on an element or fetch/XHR). This will >> not >> cause any visible breakage or errors on the page for the user, but >> it will >> silently prevent conversion measurement for sites that rely on this >> attribute. >> - >> >> attributionsrc in window.open(): The attributionsrc feature in >> the features string of a window.open() call will be ignored. >> The window will still open as requested, but no attribution source >> will be >> registered. This will not cause any visible breakage or errors on >> the pages >> for the user, but it will silently prevent conversion measurement >> for sites >> that rely on this functionality. >> - >> >> AttributionReportingRequestOptions and the attributionReporting >> member in RequestInit: The attributionReporting property within >> the options of a fetch() call will be ignored. The fetch request >> will still >> be made, but it will not trigger any attribution-related >> functionality. >> This change will not cause any JavaScript errors, but conversion >> measurement that relies on the fetch requests will no longer work. >> - >> >> Attribution-Reporting-Eligible and Attribution-Reporting-Support >> headers: Since the browser will no longer process the >> attributionsrc attribute or the attributionReporting property >> in requests, it will no longer send these two headers on outgoing >> requests. >> - >> >> attribution-reporting permission policy: The >> attribution-reporting permission policy >> >> <https://wicg.github.io/attribution-reporting-api/#permission-policy-integration> >> will be removed along with the API. Since the API it controls will >> no >> longer exist, the permission policy will have no effect and its >> removal is >> not considered a breaking change. >> >> >> >> Planning and Estimated Milestones >> >> Deprecate the browser API surface in M144 and remove in M150. >> >> There will be one aspect of ARA 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 ARA surface as >> a whole. Since this impacts post-facto server-side operations, it will not >> incur any user-facing breakage. >> >> Currently ~20% >> <https://chromestatus.com/metrics/webfeature/timeline/popularity/282> of >> page loads use the Attribution Reporting API. While ARA’s usage as a >> percentage of page loads is quite high, 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 <https://privacysandbox.google.com/overview/status>. >> >> We will proactively work toward reducing ARA 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. >> >> Link to entry on the Chrome Platform Status >> >> https://chromestatus.com/feature/6320639375966208 >> >> -- >> 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/beb44d6a-aae5-4664-994a-38fb93bb4580n%40chromium.org >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/beb44d6a-aae5-4664-994a-38fb93bb4580n%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/54acf866-c208-4770-a3bc-0d8100a97fban%40chromium.org > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/54acf866-c208-4770-a3bc-0d8100a97fban%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/d78e1296-89b1-432e-8f59-cd0c9cda9325%40chromium.org > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/d78e1296-89b1-432e-8f59-cd0c9cda9325%40chromium.org?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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