In order to grok the concept of scalability, I've drawn a series of graphs. Talking about "scalability" is hard because we translate those numbers into "performance". But the two concepts are unrelated. We say things like "NodeJS is 85% as fast as Nginx", but speed doesn't matter, scalability does. The important difference in those two is how they scale, not how they perform. I'm going to show these graphs in this post.