Browser Monitoring with New Relic: Core Web Vitals and Real User Data

Real user monitoring measures performance in your users’ browsers, not yours

Server response time is only half the story. New Relic Browser captures Real User Monitoring (RUM) — what actual visitors experience on real devices and networks. This is where Core Web Vitals live.

Why Real User Monitoring Matters

Synthetic tests run from clean data centres. Your users are on mobile networks with old phones and ad blockers. RUM tells you the truth about page load, interactivity, and errors in the wild.

Core Web Vitals

Metric Measures Good
LCP Largest Contentful Paint (load) < 2.5s
INP Interaction to Next Paint (responsiveness) < 200ms
CLS Cumulative Layout Shift (visual stability) < 0.1

Core Web Vitals connect performance directly to user experience and SEO

Beyond Vitals

New Relic Browser also captures:

  • JavaScript errors with stack traces and affected sessions
  • AJAX timing for slow API calls from the client side
  • Session traces — a timeline of a single user’s page interactions
  • Page views by geography, browser, and device

Installing the Browser Agent

If your app already uses APM, enable browser monitoring with a copy-paste snippet or auto-injection:

<!-- New Relic Browser snippet goes in <head>, before other scripts -->
<script type="text/javascript">/* provided by New Relic */</script>

Optimising LCP often means fixing the same slow backend call APM already flagged — the two views reinforce each other.

What to Learn Next

  • Connecting Browser to APM for full front-to-back traces
  • NRQL on PageView events for custom funnels
  • Alerting on Core Web Vitals regressions

Arivanandhan Chitheshwaran