JCH Optimize Pro is the paid edition of JCH Optimize for WordPress. It works across HTML, CSS, JavaScript, images, and page caching, with the aim of reducing browser downloads and the requests needed to render a page. Automatic settings apply recommended performance strategies, while Pro includes controls for sites that need more detailed choices over resource delivery. These changes can support work on First Contentful Paint, Largest Contentful Paint, Speed Index, Cumulative Layout Shift, Time to Interactive, and Total Blocking Time.

How assets are prepared and loaded

The add-on can minify CSS, JavaScript, and HTML by removing unnecessary whitespace and other characters. It can combine CSS and JavaScript documents and manage the resulting combined files. Critical CSS and JavaScript can be placed inline, while non-critical resources can be deferred to reduce render-blocking activity.

• Lazy-load offscreen and hidden images.
• Add width and height attributes to images to help reduce layout shifts.
• Enable text compression with server instructions in the site's .htaccess file.
• Preload critical resources identified for individual pages.
• Use page caching to reduce initial server response time and improve time to first byte.

Pro controls and support

The Pro edition adds HTTP/2 support, unused CSS removal, lazy-loading for iframes, picture optimization, and support for using multiple domains with a CDN. It also provides access to the Optimize Image API.

A subscription includes premium technical support through a ticket system, help configuring the plugin to resolve conflicts and improve performance, and access to downloads of new versions. This support can help when automatic combining or delivery changes need adjustment for a particular site.

When settings need adjustment

JCH Optimize Pro can be useful when large stylesheets, scripts, images, or many page components affect loading behavior, including when working on PageSpeed Insights or GTmetrix results. Exclusions let you leave out files or extensions that do not work well with combination settings. Other tools include the Sprite Generator, image attributes, lazy-loaded images, CDN or cookieless domain settings, and CSS delivery optimization.

Install and configure

1. Install and activate JCH Optimize Pro.
2. Temporarily deactivate existing page caching features and add-ons.
3. Start with Automatic Settings, from Minimum through Optimum, to configure CSS and JavaScript combining and related groups.
4. Test the site, then add optimization capabilities individually according to its needs.
5. Use exclusions for files or plugins that conflict with combination settings.
6. Flush all caches before re-enabling other caching features and plugins.

To check whether combining is active, view the page source in a browser and look for the aggregated CSS and JavaScript file URL in place of the original file links.