Apache is a free and open-source cross-platform web server software.
Drupal Multisite enables separate, independent sites to be served from a single codebase.
Drupal is a free and open-source web content management framework.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
Mautic is a free and open-source marketing automation tool for Content Management, Social Media, Email Marketing, and can be used for the integration of social networks, campaign management, forms, questionnaires, reports, etc.
Modernizr is a JavaScript library that detects the features available in a user's browser.
Varnish is a reverse caching proxy.