Client (computing)

As part of the client–server paradigm of computer networks, a client is any piece of computer hardware or software that connects to a server in order to access a service that the server has made accessible to other clients. When the server is located on another computer system—which isn't always the case, although it usually is—the client gains access to the service via the use of a network.

A programme or computer that, as part of its function, depends on making a request to another programme or piece of computer hardware or software that accesses a service made accessible by a server is known as a client (which may or may not be located on another computer). Web browsers, for instance, are examples of clients since they connect to web servers in order to receive web pages for display. Email clients retrieve email from mail servers. A number of different clients are used in online chat, each of which operates in accordance with a specific chat protocol. On each individual computer, a client instance of a multiplayer video game or an online video game may operate. The word "client" may also be used to people who make use of client software as well as computers or other devices that are used to execute client software.

A client is one half of the client–server concept, which is still prevalent in modern computer systems. Clients and servers might both be computer programmes that are executed on the same device and communicate with one another through inter-process communication methods. When combined with Internet sockets, the Internet protocol suite enables applications to connect to a service that is running on a system that is potentially located in another location. The servers are waiting for possible clients to begin connections with them before they can decide whether or not to accept them.

The phrase was first used to refer to computing devices that did not have the ability to execute their own independent programmes but could communicate with distant computers via the use of a network. The time-sharing mainframe computer served as a client for each of these computer terminals.