xPL is an open protocol intended to permit the control and monitoring of home automation devices. The primary design goal of xPL is to provide a rich set of features and functionality, whilst maintaining an elegant, uncomplicated message structure. The protocol includes complete discovery and auto-configuration capabilities which support a fully "plug-n-play" architecture - essential to ensure a good end-user experience.
xPL benefits from a strongly specified message structure, required to ensure that xPL-enabled devices from different vendors are able to communicate without the risk of incompatibilities. [1]
Communications between xPL applications on a Local Area Network (LAN) use UDP on port 3865.[2]
xPL development has primarily occurred in the DIY community, where users have written connecting software to existing protocols and devices. Some examples include bridges to other home automation protocols like Z-Wave[3] and UPB.[4] Commercially, the Logitech SqueezeCenter software for the Squeezebox supports xPL.[5]