Integrates PageSpeed Insights optimization into MODX Revolution


This extra is designed for easier integration of PageSpeed Insights optimization for MODX Revolution. It can:

  • Operate in automatic mode, if default configuration properties are enough.
  • Generate critical path CSS rules.
  • Handle subresources via API and download Google Fonts.
  • Merge and minify styles, scripts and JSON. Minify HTML content.
  • Download and cache assets. Add preconnect tags.
  • Compute SRI hashes for files and add defer or async attributes to script tag.
  • Convert gif, jpg and png images to webp format if browser supports it.
  • Manage and efficiently cache multiple configurations at once.
  • Output MODX timing tags to browser console for members of Administrator user group.


When subresources property is not set, plugin looks for subresources in HTML and processes them.
Only subresources from subresources property are processed.


            &minify=`html link script`
                "link" : [
                    { "name" : "", "version" : "", "filename" : "", "media" : "" },
                    { "url" : "", "media" : "" }
                "script" : [
                    { "name" : "", "version" : "", "filename" : "", "media" : "" },
                    { "url" : "", "media" : "" }

Script properties:

Optional. Default is true. Enables CSS assets download. Value is interpreted as a boolean.
Optional. Default is false. Async attribute value for script subresource. Value is interpreted as a boolean.
Optional. Default is true. Enables critical path CSS generator. Value is interpreted as a boolean.
Optional. Default is anonymous. Crossorigin attribute value for subresource. Case insensitive. Possible values are: anonymous, use-credentials.
Optional. Default is true. Defer attribute value for script subresource. Value is interpreted as a boolean.
Optional. Default is sha256. Algorithms to use for subresource integrity hashing. Case insensitive. Possible values are: sha256, sha384, sha512, or any their combination.
Optional. Default is 604800. Subresource cache lifetime.
Optional. Default is html link script. Determines types of content that will be minified. Case insensitive. Possible values are: css, css-attr, html, js, js-attr, json, link, script, or any their combination.
  • css - inline CSS.
  • css-attr - style attributes.
  • html - HTML content.
  • js - inline JS.
  • js-attr - event attributes.
  • json - inline JSON and JSON+LD microdata.
  • link - CSS files.
  • script - JS files.
Optional. Default is false. Enables preconnect tag management. Value is interpreted as a boolean.
Optional. Default is -1. Enables convertion of gif, jpg and png images to webp format with specified quality. Possible values are integer from 0 to 100.
Optional. Default is built by automatic mode. JSON object, containing information about subresources, their versions and files. Either subresource URL or name parameter for API is required, while media attribute is optional. For API all other properties are replaced by API defaults, if unspecified.
Optional. Default is PageSpeed.tplBeacon. Template for critical path CSS beacon.
Optional. Default is PageSpeed.tplConsole. Template for information in browser console.
Optional. Default is PageSpeed.tplLinkPreconnect. Template for link tags with preconnect attribute.
Optional. Default is PageSpeed.tplLinkStylesheet. Template for link tags with stylesheet attribute.
Optional. Default is PageSpeed.tplScript. Template for script tags.


Adding custom inline style or script. Please note, that this will force the creation of new configuration instance, if data differs on page load. Do not use this for third-party code, like Google Analytics:

            html {
                color : [[+color]];
            console.log( '[[+id]]' );
        	if( typeof performance === 'object' )
        		performance.mark( '[[++site_name]]' );

Automatic processing mode without local assets cache:


Most recent jQuery with daily updates from

                "script" : [
                    { "url" : "" }

Most recent Bootstrap with defer attribute for script subresources and weekly updates from

                "link" : [
                    { "name" : "twitter-bootstrap", "filename" : "css/bootstrap.min.css" }
                "script" : [
                    { "name" : "jquery" },
                    { "name" : "popper.js", "filename" : "umd/popper.min.js" },
                    { "name" : "twitter-bootstrap" }


Simultaneous execution is prevented by System V Semaphores extension. Cache can be refreshed manually from Manage / Clear Cache / PageSpeed menu. When using automatic conversion of gif, jpg and png images to webp format make sure to have 80% more free space for cache. Automatic mode can not and will not handle any MODX confiuration ever by itself. This extra uses a Minify library.