Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Zendesk is a cloud-based help desk management solution offering customizable tools to build customer service portal, knowledge base and online communities.