Beginners guide to gateways and proxies

Photo by William Bout on Unsplash

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, Traefik, Gloo, Kong, Ambassador, and many others. You are probably using gateways each time without even knowing it.

A gateway usually lives between clients and backing applications or services. Gateways’ job is to proxy or “negotiate” the communication between the client and the server. Imagine walking into a mall through the main entrance. As you walk in you probably run into one of these things:

Mall Directory — photo by Steven Damron (https://www.flickr.com/photos/sadsnaps/)

A mall directory. Regardless of which mall you go to, you will run into a directory that displays the names of all shops, their locations and probably includes a map as well. Let’s say you want to visit the Lego store. You know the store is in the mall, but you don’t know the exact address (why should you?!). Luckily, it’s enough to know the name of the store and use the directory to find where the store is inside the mall.

Now if we think of a mall as a server (or a cluster of servers), then the stores in a mall are services or applications running on that server. The…