Real User Monitoring (RUM) Standards
Core Web Vitals & Diagnostics
Open Analytics automatically instruments Google Core Web Vitals using the native PerformanceObserver API without slowing down your user experience.
LCP
Largest Contentful Paint
Measures perceived loading speed by recording when the main content of a page is rendered.
Good≤ 2.5 s
Needs Imp.2.5 s - 4.0 s
Poor> 4.0 s
INP
Interaction to Next Paint
Assesses overall page responsiveness by measuring the latency of every user click, tap, and keypress.
Good≤ 200 ms
Needs Imp.200 ms - 500 ms
Poor> 500 ms
CLS
Cumulative Layout Shift
Quantifies visual stability by measuring unexpected layout shifts of visible elements.
Good≤ 0.1
Needs Imp.0.1 - 0.25
Poor> 0.25
FCP
First Contentful Paint
Marks the time at which the browser renders the first bit of content from the DOM.
Good≤ 1.8 s
Needs Imp.1.8 s - 3.0 s
Poor> 3.0 s
TTFB
Time to First Byte
Measures the time between the request for a resource and when the first byte of a response arrives.
Good≤ 800 ms
Needs Imp.800 ms - 1800 ms
Poor> 1800 ms