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12 november 2020, 07:00


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.
  • Convert gif, jpg and png images to webp format, if browser supports it, with or without caching. Adjust converted image size and quality.
  • Generate critical path CSS rules, detect and preload required fonts.
  • Add font-display property to @font-face declarations.
  • Set crossorigin attribute and compute SRI hashes.
  • Manage and efficiently cache multiple configurations at once.
  • Apply native lazy loading for img and iframe elements.
  • Minify styles, scripts, JSON and HTML content.
  • Add defer or async attribute to script tags.
  • Handle subresources via API and download Google Fonts.
  • Process meta and link tags with http-equiv and preconnect attributes.
  • Output MODX timing tags to browser console for members of Administrator user group.

You can buy this extra on Modstore.


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


This is not a working configuration example, but an overview of all available properties.

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

Script properties:

Property Description
convert Optional. Default is static. Enables convertion of gif, jpg and png images to webp format with specified quality. Case insensitive. Possible values are: disable, dynamic, static.
  • disable - images are not converted.
  • dynamic - images are not cached after convertsion. Requires additional CPU resources.
  • static - images are cached after conversion. Requires additional free space.
critical Optional. Default is true. Enables critical path CSS generator. Value is interpreted as a boolean.
crossorigin Optional. Default is anonymous. Crossorigin attribute value for subresource. Case insensitive. Possible values are: anonymous, use-credentials, or empty value.
display Optional. Default is swap. font-display CSS property value. Case insensitive. Possible values are: auto, block, swap, fallback, optional.
integrity Optional. Default is sha256. Algorithms to use for subresource integrity hashing. Case insensitive. Possible values are: sha256, sha384, sha512, any their combination or empty value.
lifetime Optional. Default is 604800. Subresource cache lifetime.
loading Optional. Default is lazy. loading attribute value for img and iframe tags. Case insensitive. Possible values are: auto, eager, lazy.
minify Optional. Default is html link script. Determines types of content that will be minified. Case insensitive. Possible values are: css, html, js, json, link, script, or any their combination.
  • css - inline CSS.
  • html - HTML content.
  • js - inline JS.
  • json - inline JSON and JSON+LD microdata.
  • link - CSS files.
  • script - JS files.
quality Optional. Default is 80. Quality of converted webp images. Possible values are integer from 0 to 100.
resize Optional. Default is true. Enables resizing of images in img tags. Value is interpreted as a boolean.
script Optional. Default is defer. Attribute to be used for script tags. Case insensitive. Possible values are: async, defer.
subresources 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.


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" }

Appending custom inline style or script can be done with PHx. 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 mode can not and will not handle any MODX confiuration ever by itself. Cache can be refreshed manually from Manage / Clear Cache / PageSpeed menu. For AjaxForm extra you need to add the following scripts after jQuery. This exaple is for automatic mode:

<script src="[[++assets_url]]components/ajaxform/js/lib/jquery.form.min.js"></script>
<script src="[[++assets_url]]components/ajaxform/js/lib/jquery.jgrowl.min.js"></script>

For manual configuration you should add them to script section of subresources property. Animated gif image processing is possible after installing Image Processing (ImageMagick) PHP extension. Simultaneous execution can be prevented by installing Semaphore, Shared Memory and IPC PHP extension. This extra uses a Minify library.

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