Real User Monitoring (RUM)

Real user monitoring (RUM) captures performance and behavior data from actual visitors as they use your product — page load times, Core Web Vitals, JavaScript errors, API latency — segmented by device, browser, geography, and connection. Unlike synthetic monitoring, which runs scripted checks from controlled locations, RUM reflects the messy reality of your real audience: the slow phone on a train, the outdated browser, the far-away region. That makes it the honest source of truth for the performance your users actually feel, and where it's costing you conversions. For SaaS builders, RUM connects engineering metrics to business outcomes — you can show that a slow region has a lower signup rate, then justify the fix. Practical note: RUM needs real traffic to be meaningful, so it's most useful once you have users; pair it with synthetic monitoring for pre-launch and low-traffic paths. Watch percentiles (p75, p95), not averages — averages quietly hide your worst experiences.