cWhy is it a question whether something is an application server vs. a web server? It’s largely due to how the design and use of the two types of servers has increasingly come to overlap as the demands on websites have grown. Many popular applications act as both web servers and application servers (think Apache HTTP Server, Express, Hapi, and Koa).Another overlap is that some web application servers use HTTP as their communication protocol. Similarly, some web servers end up looking like application servers because they have built-in modules and functionality that natively support popular languages like PHP, or proxy and translate requests from HTTP into the protocol (such as FastCGI) used by the application.