Danny van Kooten

Basic profiler for WordPress Plugins. Benchmarks any given plugin by testing response times with and without the plugin activated.
<blockquote>
Plugin Profiler is on GitHub.
Bug reports (and pull requests) are welcomed on the <a href="https://github.com/dannyvankooten/wp-plugin-profiler" rel="nofollow ugc">Plugin Profiler GitHub repository</a>.
Please note that GitHub is not a support forum.
</blockquote>
<h4>Profiling a plugin</h4>
This plugin measures response times of any URL on your website in the following ways.
<ul>
<li>No plugins activated</li>
<li>Only the selected plugin(s) activated</li>
<li>All but the selected plugin(s) activated</li>
<li>All plugins activated</li>
</ul>
It then plots the response times in a chart and calculates the average response time time difference.
While this way of profiling a plugin is very low-tech it can be interesting to measure the impact of a plugin on your site’s response time. 
Please note that this way of benchmarking leaves a lot of factors out – like additional HTTP requests caused by a plugin, etc..
<h4>Installing Plugin Profiler</h4>
Since this plugin needs to filter out which plugins are activated for the profiling requests, it needs to be installed as a must-use plugin so it’s loaded early.
Have a look at the <a href="https://wordpress.org/plugins/plugin-profiler/installation/">installation instructions</a> for details.
More information
<ul>
<li>Developers; follow or contribute to the <a href="https://github.com/dannyvankooten/wp-plugin-profiler" rel="nofollow ugc">Plugin Profiler plugin on GitHub</a></li>
<li>Other <a href="https://dannyvankooten.com/wordpress-plugins/#utm_source=wp-plugin-repo&utm_medium=link&utm_campaign=more-info-link" rel="nofollow ugc">WordPress plugins</a> by <a href="https://dannyvankooten.com#utm_source=wp-plugin-repo&utm_medium=link&utm_campaign=more-info-link" rel="nofollow ugc">Danny van Kooten</a></li>
<li><a href="https://twitter.com/dannyvankooten" rel="nofollow ugc">@DannyvanKooten</a> on Twitter</li>
</ul>

Plugin Profiler

The plugin is currently working, and showing the load time of all plugins, no plugins, all but one plugin you specify, and that one plugin only. Pretty good for showing clients how much their plugins are slowing down their site. I like this plugin better than the p3 profiler.

WARNING: Copying and pasting the profiler.php file from the installation instructions will cause a white screen of death. You need to replace the quotes with normal quotes.

Works with WP 4.9

Basic plugin profiler. Benchmarks response times with and without a given plugin activated.

Forge12 Interactive GmbH

F12 Profiler analyzes your WordPress site comprehensively and delivers concrete, prioritized recommendations to improve load times. The plugin combines server diagnostics, asset analysis, database optimization, and plugin impact assessment in a modern, clean interface.
<h4>Features</h4>
Analysis & Diagnostics
<ul>
<li>Server analysis (PHP, MySQL, OPcache, web server, SSL, HTTP/2, compression)</li>
<li>Automatic site crawler with load time measurement (desktop & mobile)</li>
<li>Asset analysis (CSS, JS, images) with optimization potential</li>
<li>OPcache status & configuration recommendations</li>
<li>PHP profiler (runtime, queries, hooks, plugin ranking, culprit analysis)</li>
<li>Plugin impact analysis (assets, hooks, queries per plugin)</li>
<li>PageSpeed Insights integration (Lighthouse Scores + Core Web Vitals + CrUX)</li>
<li>Performance score with 6 weighted categories (A-F grades, trend delta)</li>
<li>Recommendation engine with automatic optimization suggestions</li>
</ul>
Optimization Tools
<ul>
<li>Lazy Loading (images and iframes)</li>
<li>Font Display Optimization (font-display: swap/optional/fallback/block)</li>
<li>Script Defer Manager (automatic defer for scripts with exclusion list)</li>
<li>Auto Image Dimensions (prevents Layout Shifts / CLS)</li>
<li>HTML Minification (whitespace, comments, empty attributes)</li>
<li>CSS/JS Minification (file-based cache)</li>
<li>WordPress Bloat Removal (emojis, embeds, Dashicons, jQuery Migrate, XML-RPC, Heartbeat, and more)</li>
<li>Browser Cache (.htaccess-based)</li>
<li>DNS Prefetch & Preconnect (domain detection from asset scan)</li>
<li>Database Analysis (8 categories with detail view)</li>
<li>Autoload Manager (granular wp_options management)</li>
<li>Background Asset Scanner with conflict detection</li>
<li>File-based Page Cache with TTL and URL exclusion (Pro)</li>
<li>CSS/JS Asset Manager – disable, defer, async per page or globally (Pro)</li>
<li>Conditional Loading – shortcode, block, regex, archive, login status, post type, plugin (Pro)</li>
<li>Smart auto-suggestions with source-based plugin detection after full scan (Pro)</li>
<li>Asset Preload Manager – Link headers for critical assets (Pro)</li>
<li>Critical CSS Generator & Applier – above-the-fold CSS per template (Pro)</li>
<li>Unused CSS Removal – per page template, safelist, regex safelist (Pro)</li>
<li>WebP Image Conversion with batch queue and backup (Pro)</li>
<li>LQIP Image Placeholders – 20px blur-up previews with IntersectionObserver (Pro)</li>
<li>Preload Key Requests – LCP images, fonts, critical resources (Pro)</li>
<li>Script Delay – delays third-party JS until first user interaction (Pro)</li>
<li>Local Google Fonts – GDPR-compliant WOFF2 self-hosting (Pro)</li>
<li>YouTube/Vimeo Facade – thumbnail + play button instead of iframe (Pro)</li>
<li>Database Cleanup – one-click per category or bulk action (Pro)</li>
<li>Redis Object Cache Management – drop-in installation/removal (Pro)</li>
<li>Scheduled Crawls & Cleanups via WP-Cron (Pro)</li>
<li>Performance Budgets with email/webhook notifications (Pro)</li>
<li>Settings Import/Export as JSON (Pro)</li>
<li>One-Click Optimizer – automated optimization with backup & restore (Pro)</li>
<li>License Management with activation/deactivation (Pro)</li>
</ul>
User Interface
<ul>
<li>Modern iOS-style design system</li>
<li>React 18 + TypeScript SPA</li>
<li>30+ pages/tools with dedicated configuration</li>
<li>Context-sensitive info sections on all pages</li>
<li>Pro features visible with lock icon and upgrade prompt</li>
</ul>
<a href="https://www.forge12.com/f12-profiler-pro/" rel="nofollow ugc">Get F12 Profiler Pro</a>
<h4>System Requirements</h4>
<ul>
<li>WordPress 6.0 or higher</li>
<li>PHP 8.0 or higher</li>
<li>MySQL 5.7 / MariaDB 10.3 or higher</li>
</ul>

F12 Profiler

Excellent! After P3 doesn’t work with PHP7+ anymore, F12 seems finally the one stepping in to fill that gap.

Update [18-Jun-19]. After some small contributions of mine to the dev efforts, the plugin developer has decided to add me to the team, long after this review was written.

Finally an alternative to P3

Comprehensive WordPress performance analysis with crawling, load time measurement, server diagnostics, and integrated optimization tools. Free.

Plugin Profiler vs F12 Profiler