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Performance

Lighthouse

Lighthouse is an automated website auditing tool that evaluates areas including performance, accessibility, and technical best practices.

Lighthouse is an automated website auditing tool that evaluates areas including performance, accessibility, and technical best practices. Optimization becomes meaningful when real-user data, repeatable lab tests, and an explicit performance budget are used together. The concept is closely related to Core Web Vitals and Real User Monitoring.

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Core Web Vitals

Real User Monitoring

Accessibility Audit

Website Performance

FAQ

Lighthouse

Where can Lighthouse be run?
Lighthouse runs in the developer tools of Chromium browsers, from the command line, and in automated pipelines. The command line suits recurring checks and budgets in deployment. Results depend on machine, network, and extensions, so a clean profile helps keep measurements comparable.
Can Lighthouse fully check a page's accessibility?
No, automated checks detect only part of the possible barriers, such as missing alt text or insufficient contrast. Whether keyboard operation works sensibly or content is understandable requires manual testing. A score of 100 is therefore no proof of WCAG conformance.
How should a Lighthouse score be read?
The score condenses weighted individual metrics into a single number. The details are more informative: which metric is weak and which recommendations follow. Two runs on the same page can differ. Comparing several measurements under identical conditions is more useful than chasing a single value.
Why is a Lighthouse score alone not enough to judge performance?
Lighthouse measures in a lab under simulated conditions, not on real visits. The score can fluctuate and often diverges from field data. Core Web Vitals rely on field data at the 75th percentile. The report is therefore suited to diagnosis and to comparison after changes, not as the sole verdict on quality.