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.

Tonya Mork

Debug Toolkit makes debugging your code easier and more enjoyable. It provides you with interactive and helpful tools:
<ul>
<li>Better PHP error interface from (<a href="http://filp.github.io/whoops/" rel="nofollow ugc">Whoops</a>)</li>
<li>Better variable inspection – no need to use <code>var_dump</code>, <code>print_r</code>, or X-debug</li>
<li>An interactive way to back trace the program’s execution order</li>
</ul>
<h3>Better PHP Error Interface from Whoops</h3>
The built-in PHP error container is basic and not as helpful as it could be. On top of that, it’s rather ugly. Wouldn’t you agree?
Whoops gives you a cool interface that is helpful, interactive, and quite nice to look at. Some features:
<ul>
<li>Provides the error message and links to search Google, DuckDuckGo, and Stack Overflow.</li>
<li>Shows the actual code where the error occurred.</li>
<li>Provides an interactive call stack. Click each and the actual code appears in the viewer panel.</li>
<li>Environment and details including GET Data, POST Data, Files, Cookie, Session, Server/Request Data, Environment Variables, and Registered Handlers.</li>
</ul>
See the tools in action in this video
<iframe loading="lazy" title="Introducing the Debug Toolkit Plugin for WordPress" src="https://player.vimeo.com/video/322351688?dnt=1&app_id=122963" width="750" height="422" frameborder="0" allow="autoplay; fullscreen; picture-in-picture; clipboard-write"></iframe>
<h3>Better Variable Inspection</h3>
Though X-debug is powerful, it can be difficult to set up and run. For that reason, it’s common to dump or print out the variable to browser. But the built-in display for the PHP <code>var_dump</code> and <code>print_r</code> is basic.
This plugin includes both two very popular variable dumper tools:
<ul>
<li><a href="https://symfony.com/doc/current/components/var_dumper.html" rel="nofollow ugc">VarDumper from Symfony</a></li>
<li><a href="https://kint-php.github.io/kint/" rel="nofollow ugc">Kint – a modern and powerful PHP debugging helper</a></li>
</ul>
VarDumper provides a simple container that displays where you place it.
On the other hand, Kint provides a more powerful interface that gives you more information such as printing out the expression that was passed into it, the data type, memory size, and the value.
To make it even easier, the following utility functions are available for you to use in your code:
<h4>Available Functions for Inspecting Variable Values</h4>
Let’s explore the functions that are available for you through this plugin. We’ll use the variable inspectors to dump <code>global $post</code>.
Note: You can pass in any variable or function that returns a value.
Dumps the given variable(s):
<pre><code>global $post;

// VarDumper
vdump( $post );

// Kint
dump( $post );
</code></pre>
Dumps the given variable(s) and then exits the program’s execution:
<pre><code>global $post;

// VarDumper
vdump_and_die( $post );

// Kint
dump_and_die( $post );
</code></pre>
In addition, there are alias (shorthand) functions available for you if you prefer shorter function names:
<ul>
<li><code>vd()</code> is an alias for <code>vdump()</code></li>
<li><code>vdd()</code> and <code>vdd()</code> are aliases for <code>vdump_and_die()</code></li>
<li><code>d()</code> is an alias for <code>dump()</code></li>
<li><code>dd()</code> and <code>ddd()</code> are aliases for <code>dump_and_die()</code></li>
</ul>
<h3>Tracing Call Stack</h3>
When debugging, there are times when you need to see the order in which functions were called that lead to a certain point in the program. PHP offers a backtrace that traces back the execution order from the point when the function is invoked.
To make backtracing easier, this plugin provides you with a <code>trace()</code> function and combines it with the variable inspect functions.
For example, if you wanted to trace the call stack to the start of the loop in your theme’s <code>functions.php</code> file, you could use this code:
<pre><code>add_action( 'loop_start', function() {
 trace();
} );
</code></pre>
<h4>Available Trace Functions</h4>
Place these functions at the point where you want to trace the call stack.
<ul>
<li><code>trace();</code></li>
<li><code>trace_vdump();</code> – Combines <code>trace()</code> and <code>vdump()</code></li>
<li><code>trace_dump();</code> – Combines <code>trace()</code> and <code>dump()</code></li>
<li><code>trace_vdump_and_die();</code> – Combines <code>trace()</code> and <code>vdump_and_die()</code></li>
<li><code>trace_dump_and_die();</code> – Combines <code>trace()</code> and <code>dump_and_die()</code></li>
</ul>
In addition, there are alias (shorthand) functions available for you if you prefer shorter function names:
<ul>
<li><code>tracevd();</code> – Combines <code>trace()</code> and <code>vd()</code></li>
<li><code>traced();</code> – Combines <code>trace()</code> and <code>d()</code></li>
<li><code>tracevdd();</code> – Combines <code>trace()</code> and <code>vdd()</code></li>
<li><code>tracedd();</code> – Combines <code>trace()</code> and <code>dd()</code></li>
<li><code>tracevddd();</code> – Combines <code>trace()</code> and <code>vddd()</code></li>
<li><code>traceddd();</code> – Combines <code>trace()</code> and <code>ddd()</code></li>
</ul>
<h3>Admin Bar</h3>
“DEBUG ACTIVE” indicator displays in the WordPress admin bar to alert you when the plugin is active.

Debug Toolkit

This is a must have plugin if you do any kind of PHP coding for WordPress. It makes the difficult aspects of debugging code easy. You'll spend less time debugging and more time writing great functionality.

Very Nice!! A must have...

Thanks for creating this. Another must have in my plugin development workflow!

Another must have!

I've just discovered this plugin after years of WP development and it's super useful! I'm not a fan of xDebugging variables; debugging big objects and arrays with dump() or vdump() is very cool, as you can easily open up and close the tree to navigate through it more easily.
Nice work!

Excellent developer companion plugin

Wonderful plugin to debug errors. A feature request would be to dump the variable in debug.log file as well when define( 'WP_DEBUG_LOG', true ); is set in config file.

Wonderful Plugin

This is a great new plugin, and I love having the option to use Kint or VarDumper, they're invaluable. Having Whoops in there is a major plus. Tonya rocks!

Part of my build setup on every site now.

A must have!

This plugin is amazing, Highly recommended for developers. 

Really worth it !

One of my favourite plugin. Helps a lot with development and debugging. Please keep it update or if we could get a chance to contribute we would love that.

Best Plugin For Devs


This is a must have developers tool. Can't work without it. Highly recommend it.


Saved me many times

Code debug made easier and more enjoyable.

F12 Profiler vs Debug Toolkit