semantic-conventions/docs/browser/events.md

Semantic conventions for browser events

Status: Development

This document defines semantic conventions for browser (web) instrumentations that emit events.

WebVital Event

Status:

The event name MUST be browser.web_vital.

This event describes the website performance metrics introduced by Google, See web vitals.

Body fields:

⚠️ Body fields will be moved to complex attributes once the semantic convention tooling supports complex attributes (see #1870).

Body Field	Type	Description	Examples	Requirement Level	Stability
delta	double	The delta between the current value and the last-reported value. See delta.	0.2	Required
id	string	A unique ID representing this particular metric instance.	v3-1677874579383-6381583661209	Required
name	enum	Name of the web vital.	cls	Required
value	double	Value of the web vital.	1.0	Required

name has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
cls	Cumulative Layout Shift. See cls.
fid	First Input Delay. See fid.
inp	Interation to Next Paint. See inp.
lcp	Largest Contentful Paint. See lcp.