Understanding how your site performs in the real world is critical to delivering a fast, engaging experience. What actually happens when people visit? Does the page load quickly and smoothly? Without unexpected movement or interaction delays? Which pages are slowest? Are users having a good time?
Today, we’re launching Calibre RUM, which captures Core Web Vitals and key UX signals directly from real browser sessions. Now, you can see exactly where your site is fast, where it’s slow, and who is affected.
The RUM Dashboard shows live visitor counts, session totals, audience locations, and Core Web Vitals trends at a glance.
Find the pages that matter most#
The Pages Leaderboard ranks your pages by traffic volume. You can sort by any metric (LCP, INP, CLS, or others) to find the pages with the worst user experience. Group pages by URL pattern (like /blog/* or /products/*) to see how vital sections of your site perform.
No guesswork. Start with the pages that affect the most users. Fix them, iterate.
Pages ranked by traffic volume, with Core Web Vitals scores for each.
See which elements are slow#
Calibre RUM identifies the specific DOM elements responsible for slow renders (LCP), interaction delays (INP), and layout shifts (CLS). Add custom attribution with data-name or elementtiming attributes so it’s clear which element or image is causing them problem.
INP Attribution Targets identifies which interactive elements cause the longest delays.
Understand your audience#
The Audience Report shows what percentage of visitors had a good, to improve, or poor experience. It segments UX experience by page, page grouping, element, country, device type, browser, and more. You’ll see which areas are affected the most, and what’s worth investigating further.
See where user experience is strong and where it suffers, segmented by country, device, browser and more.
Privacy-first by design#
Calibre RUM collects no cookies, no personal data, and no IP addresses. Session identifiers live in sessionStorage and are discarded when the tab closes. The script supports signature-based subresource integrity (SSRI) to prevent supply-chain tampering, and you can optionally exclude EEA/EU visitors entirely. Learn about data collection, processing, retention, and more.
Predictable, controllable costs#
You set the session sampling rate and data retention period. Monitor at a level that matches your requirements, and budget. Sample by 15% of user sessions or 100%. Hard stop billing, or flexible, it’s up to you.
Get started in minutes#
RUM is included on Free Trial, Starter, Team, and Company plans.
Navigate to Site → Real User Monitoring → Settings to enable it, or read the installation guide or documentation.
You can also read more about the launch in our blog post.