TV: A Google account, a stadia Controller, and Google Chromecast Ultra
PC: A Google account, a recent version of the Chrome browser
Phone: A Google account, and a mobile device supported by Stadia (Android version of the app requires a mobile device running Android 6.0 or greater)
See below for all supported devices:
Stadia recommends a download speed of at least 10 Mbps to stream games and faster speeds for resolutions greater than 720p. Test your connection.