A plugin for MODX Revolution (2.3+) to minify the output Markup (XHTML/HTML4/HTML5). The compression is at about 20% for each page depending on your markup.
Based on the Minifier: phpwee-php-minifier from searchturbine - https://github.com/searchturbine/phpwee-php-minifier/tree/master
Install Package via MODX Package Management. The plugin will be installed and run on the event "OnWebPagePrerender".