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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