Core Web Vitals evidence guide.

What to verify

A trustworthy performance review separates 28-day real-user field data from a repeatable lab diagnosis. TechTenstein does not invent field data when an origin has too little public traffic or an API is unavailable.

1. Check origin and individual URL field data for LCP, INP and CLS.
2. Record device, location, network, date and tool version for lab runs.
3. Find the slow resource or interaction in a trace before changing code.
4. Re-run the same setup and wait for the field-data window before claiming impact.

How to use this guide

1. Run the free website audit tool. It checks up to five public pages on one website plus its robots and sitemap endpoints, and the result stays in your short-lived session.
2. Verify the finding with owner-controlled data where it exists, such as Search Console, Bing or Chrome UX Report (CrUX) field data. The audit does not submit pages to Google or change the website.
3. Fix the agreed issue, then run the same check again. Mark an issue verified only when it disappears from new evidence.

For the human checks that HTML alone cannot prove, use the website audit checklist.