HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
ipstack is a real-time IP to geolocation API capable of looking at location data and assessing security threats originating from risky IP addresses.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
PHP is a general-purpose scripting language used for web development.