An open-source, automated tool built into Google Chrome for evaluating web performance, accessibility, best practices, and foundational SEO.
Lighthouse is an automated tool for assessing aspects of a web page’s quality. It runs checks in areas such as performance, accessibility and SEO and produces findings that can guide investigation. A report describes the tested page under a particular run, not a complete certification of the whole website.
Its performance results are especially sensitive to the test conditions. Device and network simulation, page state and competing activity can influence a run. Record how the test was performed and compare equivalent conditions when evaluating a change. A different score alone does not explain whether actual customers experienced an improvement.
Automated checks also have boundaries. A page can pass a technical check while still confusing a reader, and accessibility requires human evaluation beyond what automation can detect. Use findings to locate likely problems, then test the actual interaction and relevant content. A perfect score is not a guarantee of rankings, accessibility compliance or successful enquiries.
Takeaway: Use Lighthouse as a diagnostic starting point, not a trophy. Choose improvements that address meaningful user problems and verify the result with appropriate functional and real-world evidence.
Example
A booking page report identifies a large image contributing to slow loading. The team optimizes that image, reruns the same test and checks the booking process on a phone. It also watches available field performance data rather than assuming the laboratory score proves every visitor’s experience.
What to check
Save the report with its URL, date and test configuration. Test important page types and interactions separately, and do not remove useful functionality solely to chase a higher automated score.
For more detail, see Chrome Lighthouse overview.