Real User Performance
Don't measure performance from a powerful lab server with perfect internet. Measure what your actual users experience in the real world.
A lab test like Lighthouse runs once, on one machine, with a clean network connection — it tells you almost nothing about what your actual visitors experience on a three-year-old phone over patchy mobile data. Real User Performance measures Core Web Vitals directly in every visitor's browser, from real traffic, not a simulation.
LCP, FCP, and load timing roll up per page and break down by device and connection type, so you can tell whether a slow page is a universal problem or something specific to mobile. Pages with poor scores surface directly in your SEO issues list instead of living in a separate performance report nobody checks.
What you get
Core Web Vitals
LCP, FID, and CLS tracked directly from your visitors' browsers, exactly how search engines score you.
Real-world load times
See how long it actually takes for a page to become visible on a 3G mobile connection vs. a desktop.
Device & network impact
Correlate slow performance directly to specific devices or connection types to know where to optimize.
No simulated lab tests
Everything reported is based on 100% real user traffic, not a simulated lab environment.
How it works
Vitals are measured in the browser
The script records LCP, FCP, and load timing directly in each visitor's browser as the page renders — not in a simulated test environment.
Numbers roll up per page and per device
See a p75 (the value 75% of visits beat) for every path, split by device and connection type.
Slow pages surface as issues
Pages with poor LCP or FCP show up in your SEO issues list, so performance problems don't get buried in a separate report.
Frequently asked questions
Is this the same as a Lighthouse score?+
No — Lighthouse runs one simulated test on one machine. This measures every real visit, so it reflects the actual range of devices and connections your users have.
Does tracking performance slow the page down?+
The metrics are read from the browser's own Performance API after the fact, so it's a passive read, not additional work the page has to do.
What if I don't have much traffic yet?+
Metrics only show once enough samples exist for a page to be meaningful, so you won't see a false "poor" score from a single slow visit.
Can I see mobile vs. desktop separately?+
Yes — performance breaks down by device and connection type, so you can tell if a problem is universal or specific to, say, mobile 3G.
Other features