What is Perfmatters plugin?
Perfmatters is a lightweight WordPress performance plugin from Forgemedia, co-founded by Brian Li and Tom Zsomborgi. Unlike full caching plugins, Perfmatters is not a caching tool — it is designed to complement a caching plugin by handling the optimizations that caching plugins tend to miss or handle poorly: script management, unused feature disabling, and per-page asset loading control.
Its core feature is a script manager that lets you disable specific plugins’ CSS and JavaScript files on specific pages or post types. If a form plugin loads its scripts on every page but you only have a form on the Contact page, Perfmatters lets you load those scripts exclusively on that page — reducing unused JS and CSS without disabling the plugin sitewide. This targeted approach is more precise than the global asset controls in most caching plugins.
Perfmatters also disables unnecessary WordPress features that add HTTP requests or database queries without providing value to most sites: Emoji scripts, oEmbeds, XML-RPC, the REST API for non-logged-in users, query string parameters on assets, the Heartbeat API, self-pingbacks, and others. These are individually small wins that collectively improve performance on many WordPress sites.
Perfmatters is paid-only at $24.95/year for a single site, making it one of the more affordable performance tools. It is most effective when paired with a caching plugin like WP Rocket, FlyingPress, or LiteSpeed Cache rather than used alone. The combination of a caching plugin for page delivery and Perfmatters for script management covers most performance optimization scenarios.
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Get Perfmatters Expert HelpKey Features
- Per-page and per-post-type script manager (enable/disable specific plugin CSS/JS per URL)
- Disable WordPress features: Emoji scripts, oEmbeds, XML-RPC, REST API for visitors, Heartbeat API, query strings
- Lazy loading for images and iframes
- Preloading of fonts, CSS, and scripts for critical resources
- DNS prefetching
Pros & Cons
Pros
- Script manager is the most precise per-page asset control tool available for WordPress
- Very affordable at $24.95/year
- Excellent complement to caching plugins — covers what they miss
Cons
- Not a standalone solution — needs a caching plugin to pair with it
- No page caching or image optimization built in
Free vs Premium
Perfmatters is paid-only at $24.95/year for a single site, $54.95/year for 3 sites, and $124.95/year for unlimited sites.
Common Problems & Fixes
Why did using Perfmatters script manager break a plugin or feature on a specific page?
The script manager disables plugin assets on the pages you configure. If a feature stops working after adding a script rule, the plugin’s JavaScript or CSS is likely being disabled on a page where it is actually needed. Review the script manager rules for that page type, and either remove the rule for the affected script or expand the rule to allow the script on the affected page. The script manager has a “load everywhere except” mode and a “load only on” mode — confirm you have selected the intended behavior.
Why is Perfmatters's "disable XML-RPC" feature blocking legitimate uses?
XML-RPC is a legacy WordPress API endpoint that can be a security risk but is also used by some legitimate tools — Jetpack, certain mobile apps, and some third-party publishing tools depend on it. If disabling XML-RPC breaks a service you use, either re-enable it in Perfmatters settings or use a more targeted approach that only blocks XML-RPC brute force attempts while keeping legitimate calls functioning.
Why are Google Fonts still loading from Google servers after Perfmatters optimization?
Perfmatters’ Google Fonts optimization works only on fonts loaded through the tag or the @import CSS method. Fonts loaded inline via style attributes or dynamically added by JavaScript after page load may not be intercepted. Also check whether your page builder or theme is loading fonts outside the standard WordPress enqueueing system, as Perfmatters hooks into the WordPress asset loading process.
Customization & Developer Notes
How does the Perfmatters script manager work in practice?
Enable the script manager in Perfmatters settings, then visit any page on your site while logged in as admin. Click the Perfmatters icon that appears in the admin bar to open the script manager overlay. You will see a list of all CSS and JavaScript files loading on that specific page. Toggle individual scripts off to disable them, or click the expand arrow to set more granular rules (disable on all pages, disable on specific URL patterns, or enable only on specific patterns). Changes apply immediately after saving.
Can I use Perfmatters to disable WordPress Heartbeat on admin pages?
Yes. Perfmatters → WordPress → Heartbeat lets you disable the Heartbeat API entirely, disable it on the frontend only, or control the frequency on admin and post editor pages. The Heartbeat API is used for auto-save, post lock notifications, and real-time features in the admin. Disabling it on the frontend only is typically the safe configuration.
Frequently Asked Questions
Do I need a caching plugin if I use Perfmatters?
Yes. Perfmatters is designed to complement a caching plugin, not replace one. It handles script management and WordPress feature optimization, but does not provide page caching, CDN integration, or CSS/JS minification. Use Perfmatters alongside WP Rocket, FlyingPress, LiteSpeed Cache, or a comparable caching tool.
Is Perfmatters worth buying if I already have WP Rocket?
Often yes. WP Rocket does not have per-page script management at the individual plugin level. Perfmatters adds that precision layer on top of WP Rocket’s broader optimizations. The combination is frequently recommended by performance consultants for sites where unused JS from inactive plugins is a measurable issue.
Does Perfmatters slow down the WordPress admin?
No. Perfmatters’ optimizations are targeted at the front end. The only admin-side change is the script manager interface in the admin bar, which has negligible impact.
What is the Perfmatters WooCommerce optimization?
Perfmatters includes a WooCommerce section that lets you disable specific WooCommerce scripts and styles on non-store pages. For example, you can disable cart and WooCommerce CSS on standard blog posts and pages where WooCommerce functionality is not needed, reducing unnecessary CSS load on those pages.