Glossary term
What is RUM (Real User Monitoring)?
RUM stands for Real User Monitoring.
In System Design
Measures what real users' browsers/apps experience. Example: Page load times by country and device.
Learn it properly · System DesignLesson 48: Monitoring, Alerting & Blameless PostmortemsSixty alerts a week, fifty-five that don't matter — so the real one gets snoozed and customers can't pay for two hours. How to build dashboards and alerts people trust, run incidents with clear roles, and write blameless postmortems that actually make the system better.In The Browser Contract
Measuring speed in the browsers of real visitors, not only in a lab test.
Learn it properly · The Browser ContractLesson 9: Core Web Vitals for Engineers: LCP, INP and CLSWhat each metric measures, its “good” limit at the 75th percentile, why INP replaced FID, and the difference between field data and lab data.