Firefly is a so-called softphone developed by Freshtel to offer cheap VoIP calls from one country to another. While fast and small, running low on hardware resources, this softphone provides many features.
Free calls and instant messaging are possible out of the box with no paid plan needed. Regarding calls to mobile and landline networks, prices vary from 4 dollars to 29 dollars.
A call shouldn’t be longer than 180 minutes.
Going back to the list of features, we have noticed its compatibility with USB handsets and standard headsets and its support for call transferring and conference mode.