ToolExperiment
Latency Lens
A browser extension that overlays Core Web Vitals on any page.
Daniel Akhile
Latency Lens
Latency Lens is an experiment in making performance visible while you browse. It overlays LCP, INP and CLS in a small corner panel on whatever page you are viewing.
It uses the same browser APIs that field tooling uses, so the numbers match what real users on your device class would see rather than a lab estimate.
#What we learned
Seeing a number change as you scroll teaches more than any report. Layout shifts we had never noticed became obvious.
Keeping the overlay itself out of the metrics took more care than the metrics did.
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