Google Cast is a proprietary protocol developed by Google for playing Internet-streamed audio/video content on a compatible consumer device. The protocol is used to initiate and control playback of content on digital media players, high-definition televisions, and home audio systems using a mobile device, personal computer, or smart speaker. The protocol was first launched on July 24, 2013, to support Google’s first-generation Chromecast player.
The Google Cast SDK was released on February 3, 2014, allowing third parties to modify their software to support the protocol. According to Google, over 20,000 Google Cast-ready apps were available as of May 2015. Support for Google Cast has since been integrated into subsequent devices, such as the Nexus Player and other Android TV devices (such as televisions), as well as soundbars, speakers, and later models of the Chromecast. Consumer devices that natively support the protocol are marketed as Chromecast built-in. As of October 2017, over 55 million Chromecasts and Chromecast built-in devices have been sold.