Thanks for the data. It's exciting to hear about such a large performance improvement.
LGTM1 Not blocking, but just curious: it would be unfortunate if the major customers of this API were ad systems. Do we have good data from non-ads use-cases? Best, Alex On Wednesday, October 21, 2026 at 6:53:04 PM UTC-7 Yoichi Osato wrote: > > This Intent mentions an OT; was there feedback from developers about the > utility of x-origin iframe pre-rendering? > Yes, one of our customers shows significant performance improvement(68%!) on > speculative loading with this feature. > > > Did we learn anything about the potential risks (e.g., to metrics and > privacy)? > No report from OT attendees so far. > > 2026年10月22日(木) 0:24 Alex Russell <[email protected]>: > >> Do we have a sense for which sorts of applications will benefit from this >> change? This Intent mentions an OT; was there feedback from developers >> about the utility of x-origin iframe pre-rendering? Did we learn anything >> about the potential risks (e.g., to metrics and privacy)? >> >> Thanks, >> >> Alex >> >> On Wednesday, October 14, 2026 at 11:28:21 PM UTC-7 Chromestatus wrote: >> >>> *Contact emails* >>> [email protected] >>> >>> *Explainer* >>> >>> https://github.com/WICG/nav-speculation/blob/main/prerendering-cross-origin-iframes.md >>> >>> *Specification* >>> https://wicg.github.io/nav-speculation/prerendering.html >>> >>> *Summary* >>> Prerenders cross-origin iframes with an opt-in response header. Browsers >>> will now prerender all cross-origin frames if the top-level frame's HTTP >>> response includes the Supports-Loading-Mode: prerender-cross-origin-frames. >>> >>> *Blink component* >>> Blink >>> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%22> >>> >>> *Web Feature ID* >>> speculation-rules <https://webstatus.dev/features/speculation-rules> >>> >>> *Motivation* >>> By default, navigational prerendering delays the loading of all >>> cross-origin iframes until the referring page activates the prerendered >>> page. However, there are some cases where cross-origin iframes are >>> particularly important to an application, such that delaying them negates >>> many of the benefits of prerendering. >>> >>> *Initial public proposal* >>> >>> https://groups.google.com/a/chromium.org/g/blink-dev/c/KP1f2UTqCgM/m/q_EQ5ceXHgAJ >>> >>> *TAG review* >>> https://github.com/w3ctag/design-reviews/issues/1207 >>> >>> *TAG review status* >>> Issues addressed >>> >>> *Origin Trial Name* >>> Prerendering cross-origin iframes >>> >>> *Goals for experimentation* >>> Gather feedback from web authors who already are interested in this >>> feature. >>> >>> *Chromium Trial Name* >>> Prerender2CrossOriginIframes >>> >>> *Origin Trial documentation link* >>> >>> https://github.com/WICG/nav-speculation/blob/main/prerendering-cross-origin-iframes.md >>> >>> *WebFeature UseCounter name* >>> kPrerender2CrossOriginIframes >>> >>> *Risks* >>> >>> >>> *Interoperability and Compatibility* >>> The entire speculative loading feature is a progressive enhancement, so >>> in general risks are low in this area. >>> >>> *Gecko*: No signal ( >>> https://github.com/mozilla/standards-positions/issues/1376) No signal >>> as of 2026-10-15 >>> >>> *WebKit*: No signal ( >>> https://github.com/WebKit/standards-positions/issues/636) No signal as >>> of 2026-10-15 >>> >>> *Web developers*: Positive Our partners have given positive feedback on >>> this feature. >>> >>> *Other signals*: >>> >>> *WebView application risks* >>> >>> Does this intent deprecate or change behavior of existing APIs, such >>> that it has potentially high risk for Android WebView-based applications? >>> No. >>> >>> >>> *Debuggability* >>> The cross-origin iframe prerendering should be debuggable as well as top >>> frame's one: >>> https://developer.chrome.com/docs/devtools/application/debugging-speculation-rules#prerender >>> >>> >>> *Will this feature be supported on all six Blink platforms (Windows, >>> Mac, Linux, ChromeOS, Android, and Android WebView)?* >>> No >>> >>> *Is this feature fully tested by web-platform-tests >>> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?* >>> Yes >>> >>> >>> *Flag name on about://flags* >>> "prerender2-cross-origin-iframes" from M148 >>> >>> *Finch feature name* >>> Prerender2CrossOriginIframes >>> >>> *Rollout plan* >>> Will ship enabled for all users >>> >>> *Requires code in //chrome?* >>> False >>> >>> *Tracking bug* >>> https://issues.chromium.org/issues/440387014 >>> >>> *Availability expectation* >>> Feature is available only in Chromium browsers for the foreseeable >>> future. >>> >>> *Adoption expectation* >>> Feature is used by specific partner(s) to provide functionality within >>> 12 months of launch in Chrome. >>> >>> *Adoption plan* >>> One of our partners has already joined in origin trial in Chrome and >>> shows better performance result. >>> >>> *Non-OSS dependencies* >>> >>> Does the feature depend on any code or APIs outside the Chromium open >>> source repository and its open-source dependencies to function? >>> No. >>> >>> *Estimated milestones* >>> Shipping on desktop 158 >>> Origin trial desktop first 147 >>> Origin trial desktop last 152 >>> Origin trial extension 1 end milestone 158 >>> Shipping on Android 158 >>> Shipping on WebView 158 >>> Shipping on iOS 158 >>> >>> *Anticipated spec changes* >>> >>> Open questions about a feature may be a source of future web compat or >>> interop issues. Please list open issues (e.g. links to known github issues >>> in the project for the feature specification) whose resolution may >>> introduce web compat/interop risk (e.g., changing to naming or structure of >>> the API in a non-backward-compatible way). >>> *No information provided* >>> >>> *Link to entry on the Chrome Platform Status* >>> https://chromestatus.com/feature/5112398709129216?gate=5121426126405632 >>> >>> *Links to previous Intent discussions* >>> Intent to Prototype: >>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/68b670ba.050a0220.270bc4.0593.GAE%40google.com >>> Intent to Experiment: >>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAAEV3p%3DzhNhfOpe8x%3DRKgxYFS9GCq_q-c8knZYRBRuijQ27o8w%40mail.gmail.com >>> Intent to Extend Experiment 1: >>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/6a45fcf5.198129d7.1d0cd0.0014.GAE%40google.com >>> >>> >>> This intent message was generated by Chrome Platform Status >>> <https://chromestatus.com>. >>> >> -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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