NGINX | High-performance Web Server and Load Balancer
Nginx is a web server which can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
According to Netcraft's November 2016 Web Server Survey, Nginx was found to be the second most widely used web server across all "active" sites (18.22% of surveyed sites) and for the top million busiest sites (27.83% of surveyed sites). (Wiki)
Nginx was written with an explicit goal of outperforming the Apache web server. Out of the box, serving static files, Nginx uses dramatically less memory than Apache, and can handle roughly four times more requests per second