Have you heard of gateways, proxies (forward and reverse), load balancers, API gateways?
You probably did, and even if you haven't you might have heard of products such as Nginx, HAProxy, Envoy, Kong, Traeif, Ambassador, Tyk, and many others. You are probably using gateways each time without even knowing it.
This article gives you a quick overview of gateways and their functions. It also includes a short tutorial that shows how HAProxy can be used in front of service and how to enable stats, deny requests, and implement rate-limiting. All source code included!
PDF and epub files