User Timing Level 3 extends the existing User Timing API to enable two new use cases: 1. Developers can pass custom timestamps to performance.measure() and performance.mark(), so as to conduct measurement across arbitrary timestamps. 2. Developers can report arbitrary metadata with performance.mark() and performance.measure(), which provides rich data to analytics via a standardized API.


Specification link

Specification being incubated in a Community Group

Status in Chromium


Enabled by default (tracking bug)

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

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Intent to Prototype url

Intent to Prototype thread

Search tags

User Timing L3, Custom User Timing,

Last updated on 2021-12-13