In short: PCs, Macs, desktops, laptops and modern mobile phones and tablets.
In more detail, you should be able to use any modern computer or mobile device with which you can view web pages on.
Not supported: Smart TVs, consoles (Playstation, XBox), budget tablets (Hudl, Kindle) and phones, low powered computing devices (like ChromeBooks, SoC devices) are not supported.
Also: You are welcome to use AirPlay on Macs with Safari and your AppleTV, and Chromecast on suitable equipment, however this use case is not formally supported. We support browser-based viewing only.
You are welcome to try using any web capable device but your experience may vary. You can only use one device at a time.