A copy still has to pass what the original passed
- LCP — largest contentful paint
- 2.5 s or less — Usually an image; check the one the capture serves
- INP — interaction to next paint
- 200 ms or less — Replaced FID in March 2024
- CLS — cumulative layout shift
- 0.1 or less — Fonts and unsized images are the usual cause
Google's thresholds for a good experience, at the 75th percentile of real visits. A capture that localizes assets usually improves the first two, because the platform's runtime is no longer in front of the paint — but it is worth measuring rather than assuming.
Source: web.dev — Core Web Vitals
The line this tool will not cross
Confirming authorization records what you told us — that the site is yours or that you have permission. It is not, and could not be, a determination of legal copyright ownership: no technical signal settles that question, so we do not claim to have settled it.