Core Web Vitals and page speed for every page

Every page's speed, measured from real visits rather than a lab test. The snippet records load time, first contentful paint and time to interactive for each page, scores them against the Core Web Vitals thresholds, and the Performance page lists the pages that need work with a note on what to improve.

What you see

On the Performance page	What it tells you
The site's figures	Load time, first paint and time to interactive, with how many visits they are measured from
Per page	The same figures for each page, slowest first
The score	Good, needs improvement or poor, by the Core Web Vitals thresholds
The note	What is slowing the page, in a sentence

A slow page that costs visitors also shows up as a signal on the Overview, ranked by how much it costs.

How it works

The timings come from the browser's own performance measurements on real visits, so they reflect the devices and networks your visitors actually use. Nothing is loaded or run to measure them; the snippet reads what the browser already knows.

Limits

Limit	What it means
Real visits only	A page nobody has visited since the snippet went on has no figures yet.
Measurement, not profiling	Clerion tells you which pages are slow and roughly why. Finding the exact script or image is a job for your browser's developer tools.

Set it up

Nothing beyond the one script tag.

Questions

Is this the same as Lighthouse?

Lighthouse measures one load in a lab. These figures come from your visitors' real loads, across their devices and networks, which is what Google's Core Web Vitals use.

Does the snippet slow the page down?

No. It loads deferred, and events are batched and sent in the background.