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.
Polyfill is a service which accepts a request for a set of browser features and returns only the polyfills that are needed by the requesting browser.
React is an open-source JavaScript library for building user interfaces or UI components.