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.

Modern Tribe, Inc.

Jonathan Brinley

Peter Chester

You can use this plugin to manually log data or to capture logging on WordPress actions. You can capture load time, memory, backrace, data dumps, urls, and server IPs.
This is designed to either be managed using wp-config.php and logging OR using the admin and debugbar plugin ( https://wordpress.org/extend/plugins/debug-bar/ ). Most of the following documentation applies equally to the settings panel or the wp-config.php vars. Either one works fine. The only exception is the DEBUG_LOG configuration which is only supported as a wp-config var.
Firstly, you can manually log things using the following function:
<pre><code>do_action( 'log', $message, $group, $data );
</code></pre>
The $group allows you to selectively output logging based on groups of log messages. The $message is the string you want to see in the log. $data is an optional parameter for the data that you want to display in the log (objects, arrays, or any other sort of data really).
To render messages to the log, you must configure wp-config.php as follows:
Run debug on only these groups. Use ‘ALL’ to debug everything. The group ‘ACTIONS’ is reserved for WordPress actions.
<pre><code>define( 'DEBUG_GROUPS', 'ACTIONS,default,myspecialgroup' );
</code></pre>
Display these outputs in the log for each log message.
<pre><code>define( 'DEBUG_PARAMS', 'time,timedelta,memory,memorydelta,data,backtrace,url,server' );
</code></pre>
WordPress actions that you wish to log.
<pre><code>define( 'DEBUG_ACTIONS', 'wp_head,switch_theme,wp_footer' );
</code></pre>
Optional restriction by URL (useful on MU installs).
<pre><code>define( 'DEBUG_URLS', 'myurl.com' );
</code></pre>
Minimum time in milliseconds required to register a log entry as being slow. Default 0 for no minumum.
<pre><code>define( 'DEBUG_MIN_TIME', 500 );
</code></pre>
Minimum memory in killobytes required to register a log entry as being heavy. Default 0 for no minumum.
<pre><code>define( 'DEBUG_MIN_MEM', 1024 );
</code></pre>
Path to log file or set to TRUE to use php error log. Default FALSE for no logging.
<pre><code>define( 'DEBUG_LOG', '/path/to/writable/log/file' );
</code></pre>
or
<pre><code>define( 'DEBUG_LOG', TRUE );
</code></pre>
<h4>Todo</h4>
<ul>
<li>Add variable for sample rate so that this could run randomly on production installs</li>
<li>Admin panel per site</li>
<li>Admin panel globally</li>
<li>WordPress error logging</li>
<li>Mysql query logging</li>
<li>WP_Error integration</li>
<li>Alerts ex: if this takes more than this much memory then log it…</li>
</ul>

Debugger

You can use this plugin to manually log data or to capture logging on WordPress actions. You can capture load time, memory, backrace, data dumps, urls …

F12 Profiler vs Debugger