LGTM3 Can you please include the link to the WPTs in the Chromestatus field? I know there's a ton of complexity here, to what extent do you believe the test suite in it's current state is sufficient to enable compatible implementations? Non-blocking, but I do think it's important that we have a high quality test suite here.
On Wed, Jun 24, 2026 at 11:25 AM Vladimir Levin <[email protected]> wrote: > LGTM2 > > On Wednesday, June 24, 2026 at 11:24:29 AM UTC-4 Alex Russell wrote: > >> LGTM1. Extremely excited about this; congrats on the launch. >> >> On Tuesday, June 23, 2026 at 1:26:11 PM UTC-7 Michal Mocny wrote: >> >>> Contact emails >>> >>> [email protected], [email protected], [email protected] >>> >>> Explainer >>> >>> https://github.com/WICG/soft-navigations >>> >>> Specification >>> >>> https://wicg.github.io/soft-navigations >>> >>> Summary >>> >>> Adds "soft-navigation" and "interaction-contentful-paint" >>> PerformanceEntry types to the web performance timeline to track >>> interaction-driven page performance, including for "soft" navigations >>> (JS-driven navigations in Single Page Apps (SPAs)). This work expands on >>> metrics like Largest Contentful Paint (LCP) and Interaction to Next Paint >>> (INP). >>> >>> The "interaction-contentful-paint" entry reports on new contentful >>> paints within parts of the page modified by a user interaction, helping >>> developers understand interaction loading latency. This proposal tracks the >>> effects of interactions across async tasks (like fetch requests). >>> >>> The "soft-navigation" entry reports same-document history state changes >>> initiated by interactions, establishing a new time origin to correctly >>> attribute subsequent performance data to the active route rather than the >>> initial document URL. >>> >>> Blink component >>> >>> Blink>PerformanceAPIs >>> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EPerformanceAPIs%22> >>> >>> Web Feature ID >>> >>> No information provided >>> >>> Motivation >>> >>> Web developers have been asking for a way to measure the loading >>> performance of "soft navigations" (JS-driven navigations in Single Page >>> Apps (SPA)), and to integrate such navigations into the web performance >>> timeline in general. >>> >>> Besides getting useful new performance insights for these, having a >>> shared standard definition for such navigations helps attribution for all >>> existing performance timeline data (i.e. resource timings), and provides >>> better default aggregation for metrics like INP or CLS with better URL >>> attribution. >>> >>> Initial public proposal >>> >>> https://github.com/WICG/proposals/issues/71 >>> >>> TAG review >>> >>> https://github.com/w3ctag/design-reviews/issues/879 >>> >>> TAG review status >>> >>> Pending >>> >>> Origin Trial Name >>> >>> Soft Navigation Heuristics >>> >>> Goals for experimentation >>> >>> 1. Gaining insights on the quality of the heuristic and how it compares >>> to current heuristics employed, from web developers, spa-framework authors, >>> and by existing RUM providers; Focusing specifically on the initial >>> "soft-navigation" reporting and the "interaction-contentful-paint" loading >>> entries that follow. >>> >>> 2. Learning if developers find the correlation of various existing >>> performance entries (i.e. Resource Timings, CLS or INP entries) to these >>> soft navigation entries more useful than without them. >>> >>> Chromium Trial Name >>> >>> SoftNavigationHeuristics >>> >>> Link to origin trial feedback summary >>> >>> https://github.com/WICG/soft-navigations/issues/47 >>> >>> Origin Trial documentation link >>> >>> https://github.com/WICG/soft-navigations#soft-navigations >>> >>> Risks >>> >>> >>> Interoperability and Compatibility >>> >>> No information provided >>> >>> Gecko: No signal ( >>> https://github.com/mozilla/standards-positions/issues/854) >>> >>> WebKit: No signal ( >>> https://github.com/WebKit/standards-positions/issues/235) >>> >>> Web developers: Strongly positive >>> >>> https://issues.chromium.org/issues/40229587 >>> >>> https://github.com/WICG/proposals/issues/71 >>> >>> https://twitter.com/yoavweiss/status/1575191332775026688 >>> >>> 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? >>> >>> None known. This feature is part of the standard performance timeline, >>> which is available in WebView in the same way as non-webview. The feature >>> is entirely implemented within blink + renderer. >>> >>> >>> Debuggability >>> >>> No information provided >>> >>> Will this feature be supported on all six Blink platforms (Windows, Mac, >>> Linux, ChromeOS, Android, and Android WebView)? >>> >>> Yes >>> >>> 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 >>> >>> soft-navigation-heuristics >>> >>> Finch feature name >>> >>> SoftNavigationHeuristics >>> >>> Rollout plan >>> >>> Will ship enabled for all users >>> >>> Requires code in //chrome? >>> >>> False >>> >>> Tracking bug >>> >>> https://bugs.chromium.org/p/chromium/issues/detail?id=1338390 >>> >>> Availability expectation >>> >>> Feature is available only in Chromium browsers for the foreseeable >>> future. This is relatively common for Performance APIs, where the >>> requirement for Baseline support is lower. A performance API can be feature >>> detected and used only on Chromium and still give developers great value. >>> >>> That said, there is existing Baseline support for the foundations of >>> this work: Event Timing, Paint Timing, and LCP-- and it seems there is >>> relatively positive support for the nascent AsyncContext and Container >>> Timing features which may make interop progress in the next year. Thus we >>> expect a future where this set of APIs also reaches interop/Baseline status. >>> >>> Adoption expectation >>> >>> At least 3 major abstractions replace their use of an existing feature >>> with this feature within 24 months of reaching mainline. Specifically, >>> several RUM measurement products and/or frameworks rely on custom >>> instrumentation, web platform api monkey-patching, and/or developer hints >>> in order to measure interactions and soft-navigations. These APIs have been >>> fairly widely deployed during origin trial by many partners/abstractions, >>> and we expect that these APIs are broadly adopted over the next few years. >>> >>> Adoption plan >>> >>> This feature has been in demand for years, and has been widely discussed >>> in relevant web performance groups (w3c web perf working group, rum >>> community group, slack, conferences, etc). Many organizations have already >>> participated in multiple rounds of OT. This feature is also expected to >>> power the next major update to the Core Web Vitals program, and has already >>> been integrated into an experimental branch of the web-vital.js library >>> which has wide industry adoption (making it an easier integration/upgrade). >>> >>> 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 >>> >>> 151 >>> >>> Origin trial desktop first >>> >>> 139 >>> >>> Origin trial desktop last >>> >>> 144 >>> >>> Origin trial extension 1 end milestone >>> >>> 123 >>> >>> Origin trial extension 2 end milestone >>> >>> 149 >>> >>> Origin trial extension 3 end milestone >>> >>> 123 >>> >>> Origin trial extension 4 end milestone >>> >>> 144 >>> >>> Shipping on Android >>> >>> 151 >>> >>> Origin trial Android first >>> >>> 139 >>> >>> Origin trial Android last >>> >>> 144 >>> >>> Shipping on WebView >>> >>> 151 >>> >>> Origin trial WebView first >>> >>> 139 >>> >>> Origin trial WebView last >>> >>> 144 >>> >>> >>> 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). >>> >>> The API shape has gone through multiple rounds of iteration and is >>> expected to be in its final form. There may be future API extensions added >>> to expose more features (i.e. to add more "container timing" details) but >>> the API was designed to gracefully support this. >>> >>> Note: the spec currently does not limit this API only the main frame top >>> level document, but the chromium implementation does. We expect to change >>> the implementation to expose InteractionContentfulPaint also to frames, but >>> may change the spec to limit SoftNavigation entries (due to complexity of >>> history stack). >>> >>> Link to entry on the Chrome Platform Status >>> >>> https://chromestatus.com/feature/5144837209194496?gate=4820517475844096 >>> >>> Links to previous Intent discussions >>> >>> Intent to Prototype: >>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAL5BFfV3qRFx0i-eGJFSzqE8bnbX8XYJCvXAj0LfvO0icPo_jA%40mail.gmail.com >>> >>> Intent to Experiment: >>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAL5BFfUb_Gn_5gGy8SnChg5KH2JN57Gv0NhnHN7Q_kH0Aa17CQ%40mail.gmail.com >>> >>> Intent to Extend Experiment 1: >>> https://groups.google.com/a/chromium.org/g/blink-dev/c/xxrmKr-6X38/m/48Hri1cnAgAJ >>> >>> Intent to Extend Experiment 2: >>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/69cd703e.050a0220.319665.006a.GAE%40google.com >>> >>> Intent to Extend Experiment 3: >>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAL5BFfULP5d3fNCAqeO2gLP56R3HCytmaNk%2B9kpYsC2dj4%3DqoQ%40mail.gmail.com >>> >>> Intent to Extend Experiment 4: >>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAEeF2TfyN4LMy2DQwjPrsTekEw8dNXgcqiogvznagjtWyfqixA%40mail.gmail.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. > 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/61471840-0ece-4ede-bfea-a57977511c0fn%40chromium.org > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/61471840-0ece-4ede-bfea-a57977511c0fn%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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