The Cassini Web Server is an open-source lightweight web server distributed with ASP.NET as an example of an ASP.NET web server written in C#.
Internet Information Services (IIS) is a web server created by Microsoft for use with Microsoft Windows
Integrated pipeline purpose
"Cassini was much better than iis express but doesn t properly support the integrated pipeline"
from question "Error Creating Debug Information - Code Won't Compile"
"Iis express is a web server albeit better than cassini iis express is not your problem"
from question "MVC4 Mobile environment on xp"
"For my webapp the integrated visual studio server cassini ist much slower than iis"
from question "How to speed up Visual Studio Webserver (Cassini)?"
"From this question i found out that iis server is better than cassini for my purpose but i don t know how to check the default server of my website"
from question "How to know the default server of my web site in asp.net?"
"What could be the reason that makes iis slower than cassini"
from question "Why is IIS slower than ASP.NET Development Server?"
"What i would suggest is to make sure you are using visual studio 2010 sp1 then install iis express which is an upgrade to cassini and is much more like real iis and then switch your project to use iis express and see if you get the same exception"
from question "Change default ASP MVC Request Header to add your own values"
"While iis does give us better performance than cassini we would still like to be able to hit f5 to run our application from within visual studio"
from question "How can I get Visual Studio Web Development Server (Cassini) to send the domain name of the request to the web application?"