An application server can be either a software framework that provides a generalized approach to creating an application-server implementation, without regard to what the application functions are or the server portion of a specific implementation instance. In either case, the server's function is dedicated to the efficient execution of procedures (programs, routines, scripts) for supporting its applied applications.

Also called an appserver, and application server is a program that handles all application operations between users and an organization's backend business applications or databases.

An application server is typically used for complex transaction-based applications. To support high-end needs, an application server has to have built-in redundancy, monitor for high-availability, high-performance distributed application services and support for complex database access.