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Event Timing API

Category

Performance

Type

New or changed feature

Status

Enabled by default (Chrome 85)

Intent stage

Shipped

Summary

Monitoring event latency requires an event listener. This precludes measuring event latency early in page load, and adds unnecessary performance overhead. The Event Timing API will enable web developers to measure event latency both before and after the page load.

Standards & signals

• Specification: https://wicg.github.io/event-timing/
• Firefox: Positive — Some positive feedback during the calls. I requested a standards position but it is still open.
• Safari: No signal — Safari: they’ve attended some of the calls but had no major feedback. Asked why it is separate from longtasks. They filed some editorial issues on the spec.
• Web developers: Positive — Positive feedback received from Alibaba (they were sad when the Origin Trial ended) and analytics providers like Akamai.
• Tracking bug: https://bugs.chromium.org/p/chromium/issues/detail?id=543598

Docs: https://github.com/WICG/event-timing

Explainers: https://github.com/WICG/event-timing/blob/master/README.md

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