A web server vs. an app server

When you research how to deploy your Rails app, you’ll see a lot of names: Apache, Unicorn, Puma, Phusion Passenger, Nginx, Rainbows, and many more. They all seem to fit under the “deploying Rails” category of software, but there’s a key difference between them. Some are “web servers,” and others are “app servers.”

Once you understand which is which, and where each category fits in your system, deployment will make a lot more sense. But the categories aren’t always clear.

What’s a web server,...