Hot swapping and hot plugging are terms used to describe the functions of replacing computer system components without shutting down the system. More specifically, hot swapping describes replacing components without significant interruption to the system, while hot plugging describes the addition of components that would expand the system without significant interruption to the operation of the system. Once the appropriate software is installed on the computer, a user can plug and unplug the component without rebooting. A well-known example of this functionality is the Universal Serial Bus (USB) that allows users to add or remove peripheral components such as a mouse, keyboard, or printer.

Hot swapping is used whenever it is desirable to change the configuration or repair a working system without interrupting its operation. It may simply be for convenience, to avoid the delay and nuisance of shutting down and then restarting complex equipment, or because it is essential for equipment to be perpetually active (server).