Performance measurement methodology

The performance score expresses how fast a website loads and responds to user interactions.

Lighthouse

We use Google Lighthouse to measure performance:

An open-source tool from Google
Tests Core Web Vitals (FCP, LCP, TBT, CLS)
Score 0–100

Why the Lighthouse score may differ

In our environment, Lighthouse typically shows a lower score than PageSpeed Insights:

Tests run in an automated environment with limited performance (GitHub Actions)
A slow mobile connection is simulated (4G throttling)
We only test the homepage

Pagespeed ONE

If you want to learn more about the performance of your website, we recommend Pagespeed.cz.

Professional performance monitoring of Czech websites
Measurements from Czech infrastructure

PageSpeed.cz is a Czech service run by industry professionals, specialising in measuring and optimising website speed. It tracks the Core Web Vitals metrics — LCP (loading speed), CLS (layout stability) and INP (interaction responsiveness) — which Google uses as a ranking factor in search. Its clients include brands such as Livesport, Dr. Max, Datart and Footshop.

Unlike synthetic tests (such as Lighthouse), it is based on real user behaviour over time, which provides more stable and representative results.