It's based on the same standard as Zigbee (802.15.4), but uses an open communication protocol that simplifies communication with Actions (Like turning on a light 75%) and Events (Like "Presence detected").

For communicating to the Internet we use a "hub", like a Raspberry pi, which has a web-based user interface and a REST API.

Yes, it is Zigbee based, it works under the same standar (802.15.4 radio frequency). For being connected to internet it needs a module that bridges the device with the internet.