Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
GoCache is an in-memory key:value store/cache similar to memcached that is suitable for applications running on a single machine.
Google Analytics is a free web analytics service that tracks and reports website traffic.
OneSignal is a customer engagement messaging solution.
Open Graph is a protocol that is used to integrate any web page into the social graph.
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.