You can use both

Wifi:  Buildxact should run fine on WiFi providing you are close enough to the router and the WiFi is reasonably strong, your home or office will generally be strongest.

Wireless dongle: Outside of your home or office you can use a wireless dongle. 

Phone as a hotspot: This will also work, though we recommended a dongle over using your phone as a hotspot  because the internet provided by a dongle is much more consistent/uninterrupted, with less dropouts.