WordPress.org

This plugin captures real user metrics about what elements are displayed on the page across a variety of device form factors (e.g. desktop, tablet, and phone) in order to apply loading optimizations which are not possible with WordPress’s current server-side heuristics.
This plugin is a framework dependency which does not provide optimization functionality on its own. For that, please install the <a href="https://wordpress.org/plugins/image-prioritizer/" rel="ugc">Image Prioritizer</a> and <a href="https://wordpress.org/plugins/embed-optimizer/" rel="ugc">Embed Optimizer</a> dependent plugins (among <a href="https://github.com/WordPress/performance/labels/%5BPlugin%5D%20Optimization%20Detective" rel="nofollow ugc">others</a> to come from the WordPress Core Performance team). There are currently no settings and no user interface for this plugin since it is designed to work without any configuration.
Your site must currently have the REST API accessible to unauthenticated frontend visitors since this is how real user metrics are collected about pages on your site; nevertheless, <a href="https://github.com/WordPress/performance/issues/1311" rel="nofollow ugc">exploration</a> is underway for providing alternative mechanisms for collecting the metrics. Also, please note that no metrics are currently collected from Safari since it does not yet support the <a href="https://developer.mozilla.org/en-US/docs/Web/API/LargestContentfulPaint" rel="nofollow ugc">Largest Contentful Paint</a> metric, but support for this <a href="https://web.dev/explore/learn-core-web-vitals" rel="nofollow ugc">Core Web Vitals</a> metric is coming this year <a href="https://webkit.org/blog/16458/announcing-interop-2025/#core-web-vitals" rel="nofollow ugc">via Interop 2025</a>.
Please refer to the <a href="https://github.com/WordPress/performance/blob/trunk/plugins/optimization-detective/docs/README.md" rel="nofollow ugc">full plugin documentation</a> for a <a href="https://github.com/WordPress/performance/blob/trunk/plugins/optimization-detective/docs/introduction.md" rel="nofollow ugc">technical introduction</a>, <a href="https://github.com/WordPress/performance/blob/trunk/plugins/optimization-detective/docs/hooks.md" rel="nofollow ugc">filter/action hooks</a>, and <a href="https://github.com/WordPress/performance/blob/trunk/plugins/optimization-detective/docs/extensions.md" rel="nofollow ugc">extensions</a> that show use cases and examples. You can also watch the talk from WordCamp Asia 2025: <a href="https://weston.ruter.net/2025/02/21/boosting-performance-with-optimization-detective/" rel="nofollow ugc">Boosting Performance with Optimization Detective</a>.

Optimization Detective

Provides a framework for leveraging real user metrics to detect optimizations for improving page performance.

pagevitals

PageVitals is a RUM plugin that integrates PageVitals into your WordPress site, monitoring real user performance metrics. Note: This plugin relies on the external PageVitals service to process data. No personal user behavior is tracked, but anonymized performance data is sent to PageVitals.
Data Collected includes: 
– Browser performance metrics (LCP, CLS, INP and other anonymous performance metrics). 
– Country (via the IP address), browser, and device type. 
– No IP addresses or user-agent strings are stored. 
– No cookies are read or written 
– No user behavior is monitored, such as mouse or keyboard events
The script is loaded via the subdomain cdn.pgvt.io and the performance data is sent to the sundomain <code>in.pgvt.io</code>.
You can visit PageVitals here: https://pagevitals.com
For full privacy details, refer to our Privacy Policy (https://pagevitals.com/privacy/) and Terms of Service (https://pagevitals.com/terms).
Benefits
PageVitals can help you:
<ol>
<li>Track Core Web Vitals: Understand critical performance metrics like LCP, INP, and CLS that directly impact your SEO rankings and user satisfaction.</li>
<li>Optimize Website Speed: By analyzing how real users experience your website, you can make data-driven decisions to improve loading times and responsiveness.</li>
<li>Identify Bottlenecks: Monitor slow-loading assets, heavy scripts, and third-party services that may be holding back your site’s performance.</li>
<li>Boost Engagement and SEO: Sites that load faster keep visitors engaged longer and improve your rankings on search engines, giving your site an edge over competitors.</li>
<li>Make Informed Decisions: Use real user data to decide what areas of your site need optimization and measure the results of your changes.</li>
</ol>
<h3>Features</h3>
<ul>
<li>Real User Monitoring: Collect real-time data from actual visitors.</li>
<li>Core Web Vitals: Monitor LCP, INP, and TTFB automatically.</li>
<li>Flexible Setup: Choose which pages to monitor and adjust CSP settings.</li>
</ul>
<h3>License</h3>
This plugin is licensed under the MIT License. For more details, see the license file included with this plugin.

PageVitals

Integrates PageVitals Field Testing (RUM) into your WordPress site.

Optimization Detective vs PageVitals