https://www.iankumu.com/blog/nginx-vs-apache/ is a high-performance web server software. It can be used as a standalone web server, a https://www.iankumu.com/blog/nginx-load-balancing/, or a reverse proxy.
Using Nginx as a reverse proxy can allow us to use other Web servers for our application servers that are specialised for their task. This means that we can have one Application server using https://httpd.apache.org/ as its web server and another application server using https://caddyserver.com/ as its web server.
Nginx is a reverse proxy server, which means it can be used as a gateway between a web server and a client.