Web Vitals & Real User Monitoring
Measure real-world performance with Core Web Vitals and detailed RUM data.
What are Core Web Vitals?
Core Web Vitals are a set of metrics defined by Google that measure real-world user experience for loading performance, interactivity, and visual stability. They directly influence your search rankings.
| Metric | Name | What it measures |
|---|---|---|
| LCP | Largest Contentful Paint | Loading performance — how long until the largest visible element renders |
| CLS | Cumulative Layout Shift | Visual stability — how much the page layout shifts unexpectedly |
| INP | Interaction to Next Paint | Interactivity — how long until the page responds to user input |
| FCP | First Contentful Paint | Perceived load speed — how long until the first content appears |
| TTFB | Time to First Byte | Server responsiveness — how long until the browser receives the first byte |
How it works
Abner collects Web Vitals automatically through abner-vitals.js, a lightweight companion script that is lazy-loaded after your page finishes loading. This means it has zero impact on your page load performance — the vitals script is only fetched once the main content is ready.
No additional installation is needed beyond the standard Abner script tag. The vitals module is loaded automatically.
Opting out
If you do not want to collect Web Vitals data, add data-vitals="false" to the Abner script tag:
<script defer data-site="YOUR_SITE_ID" data-vitals="false" src="https://www.abner.app/abner.js"></script>RUM dashboard
View your Web Vitals data in the RUM dashboard at /sites/<id>/rum/. This feature is available on Pro and Business plans.
Pro plan
The Pro plan includes aggregate LCP, CLS, and INP scores with a good / needs improvement / poor breakdown. This gives you an at-a-glance view of how your site performs for real visitors.
Business plan
The Business plan includes full Real User Monitoring with detailed breakdowns by page, device type, browser, and country. It also includes histograms showing the distribution of each metric, so you can identify outliers and understand the full range of your visitors' experience.
Rating thresholds
Each metric is rated as Good, Needs Improvement, or Poor based on the following thresholds:
| Metric | Good | Needs Improvement | Poor |
|---|---|---|---|
| LCP | ≤ 2500 ms | ≤ 4000 ms | > 4000 ms |
| CLS | ≤ 0.1 | ≤ 0.25 | > 0.25 |
| INP | ≤ 200 ms | ≤ 500 ms | > 500 ms |
| FCP | ≤ 1800 ms | ≤ 3000 ms | > 3000 ms |
| TTFB | ≤ 800 ms | ≤ 1800 ms | > 1800 ms |
These thresholds follow Google's official Web Vitals guidelines. For more details on the base script setup, see the Installation guide.