What is the TL;DR of the category? What do tools in this category let you do?
These tools allow computers to deal with incoming requests for data on the Internet.
Why would I need to use it? Why would I need to start using it?
One would use these tools if creating an application that lives on the Internet.
Where in the Back-End design/pipeline is this category of tools used? Learn more.
These tools would reside on the server computer and act as the first responder to incoming web requests from web clients. They go in front of the website or web application data.