Googlecast lets you cast apps from your device to the TV and it's Google’s latest foray in an effort to dominate the big screen. The device can be controlled by a phone or tablet running on Android or iOS, or a laptop running Chrome OS, Mac OS, or Windows. And at a cost of just $35 who wouldn't want one?
How does it work? A sender application running on the mobile device or computer uses the Google Cast API appropriate to its operating system to discover and transmit to the receiver application running on Googlecast. Developers can use the sender APIs to enable Android, iOS, or Chrome apps to send content. According to Google, many devs have found that adding Google Cast support to an existing app takes less than 200 lines of code.
Chromecast runs a scaled-down Chrome browser with a receiver app that receives data over Internet Protocol and transmits it to the TV via HDMI. The receiver API lets devs customize the messaging between the sender and receiver applications for authentication and other scenarios.
Check out more at https://developers.google.com/cast/devprev.