Apache is a free and open-source cross-platform web server software.
PHP is a general-purpose scripting language used for web development.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
Typekit is an online service which offers a subscription library of fonts.
Varnish is a reverse caching proxy.
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.