I saw in a few comments people talking about having a HAProxy in front of a Nginx, which in turn acts as the reverse proxy to the app instances.

I wanted to understand what use-cases is this architecture viable and recommended, if you could just remove the HAProxy and have Nginx as the public facing server or maybe remove the Nginx altogether, and if there are other factors to use the HAProxy and the Nginx, such as pairing them with a few Varnish instances.

Thanks a lot for your time