fastmon vs Lighthouse
Keep the lab.Add the field.
Lighthouse tells you how fast one simulated device loaded your page. fastmon shows you how fast it was for your real visitors, and still runs Lighthouse for you, on a schedule.
Lighthouse is a great, free lab tool. It loads your page once on a simulated device under ideal conditions and scores it. That is perfect for catching regressions before you ship, and fastmon runs exactly that for you as Synthetic Monitoring.
But a lab score is not what your visitors feel. A three-year-old phone on mobile data is not an idealized desktop. fastmon adds Real User Monitoring: the Core Web Vitals your real visitors actually get, aggregated at the p75, right next to the lab run. You keep the lab and gain the field.
Lab and field
Side by side, in one tool.
fastmon runs Lighthouse for you and adds the real-user data a lab test can never see.
| fastmon | Lighthouse | |
|---|---|---|
| Lab audits (Lighthouse) | ||
| Real-user field data (RUM) | ||
| Measures your visitors' real devices | ||
| Core Web Vitals at the p75from real visitors | ||
| INP (a field-only metric) | ||
| JavaScript errors from production | ||
| Server-Timing and network from real visits | Single load only | |
| Segments by country, device and page | ||
| Scheduled, continuous monitoring | Manual or CI | |
| Alerts and release tracking | ||
| Dashboard with history | One-off report | |
| Price | from €29/mo | Free |
Lighthouse is free and open-source, and fastmon uses it for its Synthetic Monitoring. This comparison is about lab-only versus lab-plus-field. As of 14 July 2026: list prices / typical configuration; individual terms may differ.
What the field adds
The three things a lab cannot show you.
Everything below only exists once real visitors load your page.
The experience, not a simulation
Real devices, real networks, aggregated at the p75, so you see what visitors actually get, not one idealized run.
INP and real errors
Interaction to Next Paint and JavaScript errors only exist in the field. Lighthouse cannot measure them at all.
Continuous, with alerts
fastmon watches every visit and alerts on regressions, instead of a score you have to remember to run by hand.
Fair play
Where Lighthouse alone is enough.
If you only need a quick lab score in CI and never look at real-user data, Lighthouse on its own is free and excellent. fastmon is for teams who also want to know, continuously, what their real visitors experience.
FAQ
fastmon and Lighthouse.
The questions people ask before they switch.
Does fastmon replace Lighthouse?
No, it includes it. fastmon runs scheduled Lighthouse audits for desktop and mobile as Synthetic Monitoring, and adds Real User Monitoring on top. You get the lab and the field in one tool.
Why is field data better than a Lighthouse score?
It is not better, it is different, and you want both. Lighthouse is a clean, reproducible lab signal. Field data is the messy truth of real devices and networks at the p75, including INP and errors a lab cannot see.
Honestly compared,
built in the EU.
The web-performance job without a US cloud: read-only by default, no cookies*, no long-lived identifiers, from €29 a month.
Light
€29/month
200,000 pageviews included.
Need debugging and all features? Standard from €99 for 1M pageviews. Enterprise on request. See all plans