Understand Your Performance Metrics
The Chrome UX (CrUX) report and Lighthouse offer two distinct approaches to evaluating your website's performance and user experience.
CrUX is a dataset that reflects how real-world Chrome users experience the web and is also the official dataset of the Web Vitals program.
Lighthouse is a free tool for web testing that evaluates your web pages' performance, accessibility, SEO, and compliance with best practices in a controlled setting.
According to Google, the key difference is: “CrUX is a collection of real-user experiences from the field, while Lighthouse is a controlled test in the lab.” However, while it’s more important to follow the data registered on the CrUX report, some sites may lack this information due to Google's criteria for discoverability and popularity. In these cases, Lighthouse evaluations step in to complete the picture.