Dashboard
Web Vitals
Core Web Vitals from the field at the 75th percentile.
Web Vitals reports Google's Core Web Vitals measured on your real visitors' devices, so you see field performance rather than a lab score.
Enable it
Turning this on takes two switches:
- Add
data-vitalsto the snippet. Its presence loads the lazy tracker chunk that measures vitals. - Confirm it in the dashboard: a "Turn on Web Vitals" card appears with an I've added it button.
<script defer src="https://websight.srexrg.me/t.js" data-site="yourdomain.com" data-vitals></script>On a high-traffic site you can sample by giving data-vitals a rate between 0 and 1, for example data-vitals="0.1" to measure 10% of page loads. See The script for the full attribute reference.
The metrics
All values are reported at the 75th percentile (p75), and ratings are computed server-side from the raw values.
| Metric | Good | Poor |
|---|---|---|
| LCP (Largest Contentful Paint) | 2500 ms | 4000 ms |
| INP (Interaction to Next Paint) | 200 ms | 500 ms |
| CLS (Cumulative Layout Shift) | 0.1 | 0.25 |
| FCP (First Contentful Paint) | 1800 ms | 3000 ms |
| TTFB (Time to First Byte) | 800 ms | 1800 ms |
Reading the screen
- p75 tiles, one per metric. Each stays hidden until it has at least 30 samples, so an early number never misleads you.
- A device toggle for All, Desktop, or Mobile.
- A trend chart, plus breakdowns by device, browser, and country.
- A per-page table with the attributed element: the DOM element responsible for that page's score.
Safari does not report INP or LCP, so those metrics reflect other browsers only. The web-vitals library measures hard page loads, so SPA soft navigations are excluded from these numbers.