An application server is a server computer in a computer network dedicated for running certain software applications.

In the latter part of the 1990s, it was thought that a massive shift over to centrally served applications was likely, and that the desktop PC would be replaced by lightweight network computers. This was, in fact, a return to the much older model of computing as it was done in the 1960s, with a large, very expensive central computer being accessed by multiple users using dumb terminals. The difference now was the widespread use of the GUI. Certain products, such as Citrix's WinFrame, became quite popular, allowing standard Windows software to be run on an NT server, and accessed from a wide variety of clients, including non-Windows platforms such as Mac and Unix. So far, this shift has not happened on the predicted scale, and serving a GUI-based application over a slow network has presented a number of technical challenges that have not entirely been solved. It remains to be seen if the prediction comes true or whether the late 90s interest turns out to have been a fad.

This term is widely used as a buzzword in the fields of:

• Distributed computing - denoting a computer running some part of some distributed computation task
• Software components - denoting a "component farm", i.e. a computer stuffed with software components ready to answer calls for usage
• Web services - denoting a machine running applications which will answer to interface calls over HTTP and XML

See also

• Application service provider
• Citrix Systems
• JBoss
• Geronimo
• JOnAS
• Zope
• Jakarta Tomcat
• BEA Weblogic
• WebObjects
• IBM Websphere