Website/Chat:

Any reasonably modern browser on any platform or mobile device

Website Browser Push Notifications:

Although it is not yet possible for iOS, Web Push Notifications are supported by browsers such as Google Chrome, Firefox, Edge, and Opera (most recent 2 versions). These browser notifications are all supported on operating systems like Linux, Windows, and MacOs.

Livestream:

Desktops:

Mac OS X with Mac OS 10.10 and higher
Windows 7 and higher

Mac OS or Windows OS hardware requirements:
2.5 GHz Dual Core Intel Core i5 and higher desktop CPU (single screen)
2.8 GHz Quad Core Intel Core i7 and higher desktop CPU (dual or triple screen)
Dual bank RAM for better performance

Tablets

Apple iOS Tablet - iOS 10 and higher
Android Tablets OS: Android 4.0 and above
Windows 10 Tablet: Windows 10 and above

2.0 Mbps up and down for single screen
2.0 Mbps up 4.0 Mbps down for dual screen
2.0 Mbps up 6.0 Mbps down for triple screen

You can find more information at the following link:
http://support.goto.com/webinar/help/system-requirements-for-attendees-g2w010003