Hi all This has been kicked off now and security reviews are done.
As an FYI, we've updated the timeline to m148 - m153 for the origin trial. There is also a new Origin Trial link here: https://github.com/WICG/container-timing/blob/main/ORIGIN_TRIAL.md Thanks Jason From: [email protected] At: 03/18/26 11:14:35 UTCTo: [email protected] Cc: Jason Williams (BLOOMBERG/ LONDON ) , Hugh Crail (BLOOMBERG/ LONDON ) , [email protected] Subject: Intent to Experiment: Container Timing Contact [email protected] Explainerhttps://github.com/WICG/container-timing Specification https://WICG.github.io/container-timing Design docs https://github.com/WICG/container-timing Summary The Container Timing API enables monitoring when annotated sections of the DOM are displayed on screen and have finished their initial paint. A developer will have the ability to mark subsections of the DOM with the containertiming attribute (similar to elementtiming for the Element Timing API) and receive performance entries when that section has been painted for the first time. This API will allow developers to measure the timing of various components in their pages. Blink component Blink>PerformanceAPIs Web Feature ID No information provided Search tagsperformance, container, timing TAG review https://github.com/w3ctag/design-reviews/issues/1034 TAG review status Issues addressed Goals for experimentation During this Origin Trial, we are primarily looking to gain insight into: ## The attribute-based instrumentation model - Usage patterns of `containertiming` - Frequency and purpose of `containertiming-ignore` - Number of annotated elements per page ## PerformanceObserver integration - Adoption of PerformanceObserver with container-timing - Whether developers batch-observe or use targeted observation - Whether buffering behavior meets developer expectations ## Entry shape and timing semantics - Whether the exposed timing values align with developer expectations relative to LCP and Element Timing - Whether additional metadata fields are needed - Whether any fields appear unused or redundant ## Edge cases and ergonomics - Nested containers - Dynamically inserted elements - Interaction with visibility changes and layout shifts Origin Trial documentation link https://blogs.igalia.com/dape/2026/02/10/container-timing-measuring-web-components-performance Risks Interoperability and Compatibility No information provided Gecko: Positive (https://github.com/mozilla/standards-positions/issues/1155) Firefox are positive and are working on an implementation: https://phabricator.services.mozilla.com/D279373 WebKit: Neutral (https://github.com/WebKit/standards-positions/issues/442) Web developers: No signals Other signals: Ergonomics Performance overhead only happens when enabling, any overhead is low because we piggy back on DOM-traversals which are already happening. Activation The feature is consistent with other Performance APIs that work on the Performance Timeline. This feature can't be polyfilled properly, there has been an attempt (see Explainer) but that has high resource usage. Today all the documentation lives in the explainer, we will hope to promote this more once it is exposed to the wider development community. Security https://github.com/WICG/container-timing/?tab=readme-ov-file#security-and-privacy 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 information provided Ongoing technical constraints None Debuggability Container Timing entries can be printed to the developer console from the PerformanceObserver. The attributes are also observable in the Elements Panel. This feature has basic support from DevTools. Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?Yes This feature is implemented in Blink and isn't subject to any platform specific APIs Is this feature fully tested by web-platform-tests? Yes https://wpt.fyi/results/container-timing/tentative?label=experimental&label=master&aligned DevTrial instructions https://github.com/WICG/container-timing?tab=readme-ov-file#chrome-canary-and-chrome-beta Flag name on about://flags enable-experimental-web-platform-features Finch feature name ContainerTiming Requires code in //chrome? False Tracking bug https://issues.chromium.org/issues/382422286 Measurement https://chromestatus.com/metrics/feature/popularity#V8Element_ContainerTimingIgnore_AttributeGetter https://chromestatus.com/metrics/feature/popularity#V8Element_ContainerTiming_AttributeGetter https://chromestatus.com/metrics/feature/popularity#ContainerTimingObserverRegistered Estimated milestones Origin trial desktop first 147 Origin trial desktop last 152 DevTrial on desktop 145 Origin trial Android first 147 Origin trial Android last 152 DevTrial on Android 145 Origin trial WebView first 147 Origin trial WebView last 152 Link to entry on the Chrome Platform Status https://chromestatus.com/feature/5110962817073152?gate=5112674898411520 Links to previous Intent discussionsIntent to Prototype: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/672cffcd.2b0a0220.d9f4a.0540.GAE%40google.com This intent message was generated by Chrome Platform Status. -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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