Apache is a free and open-source cross-platform web server software.
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.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
MailerLite is an email marketing tool and website builder for businesses of all shapes and sizes.
Modernizr is a JavaScript library that detects the features available in a user's browser.
PHP is a general-purpose scripting language used for web development.