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.


Editor's draft

Status in Chromium


Enabled by default (tracking bug) in:

  • Chrome for desktop release 78
  • Chrome for Android release 78
  • Android WebView release 78

Consensus & Standardization

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

  • No signal
  • Positive
  • No signal
  • No signals


Intent to Prototype url

Intent to Prototype thread

Search tags

User Timing L3, Custom User Timing,

Last updated on 2021-05-31