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.

vikinguard

Vikinguard collects performance data from your site providing you with meaningful information about:
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Your site availability.Vikinguard tests your site constantly from many locations all around the world and notifies you when something goes wrong, like when your site is down or not performing properly.
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The real experience of your site’s users. Real User Monitoring is the only way to understand the real experience of each single visitor navigating in your site. This is the best way to understand what should be done in order to improve your website’s performance and answer questions like what is the user experience from a specific country, at what time you get the most of your users traffic, …
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Your site performance/load time. It will provide you with visibility about what is the expected load time of your site before any user access your site, as well as when they are accessing. Vikinguard will provide you with some advices to improve your site performance (remember that SEO takes into account page load time…).
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Failures. Vikinguard will provide you with visibility of the failures that were experienced by your users and will notify you in advance is we detect any performance issue before any end user experiences it.
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For more information: <a href="https://vikinguard.com" title="Vikinguard" rel="nofollow ugc">vikinguard.com</a>. Please note that you need a Vikinguard account for this plugin. If you don’t have one yet, don’t worry, you can create one during the installation process.

Vikinguard

With Vikinguard you'll know the real user experience of your site and you'll be notified when something is not performing as expected.

Optimization Detective vs Vikinguard