Apache is a free and open-source cross-platform web server software.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
Slider Revolution is a flexible and highly customisable slider.
Smart Slider 3 is a responsive, SEO optimised WordPress plugin.
WordPress is a free and open-source content management system written in PHP and paired with a MySQL or MariaDB database. Features include a plugin architecture and a template system.
WPBakery is a drag and drop visual page builder plugin for WordPress.