A server is a computing platform capable of listening for external requests (from clients) and serving responses to those requests; this interaction is referred to as the client-server relationship.

A server can be:

• A computer
• A virtual computer (a computer created via software)
• A peripheral, such as a printer

The ability to serve requests is usually conferred by installing server software on a computing platform and then configuring the computing platform appropriately (though individual applications are also capable of functioning as servers on their own). Server software designed to create a web server (a server capable of serving HTTP requests) is called web server software.