The open source software is designed for connecting amateur radio operators who are operating under weak signal conditions and offers real-time keyboard-to-keyboard messaging, store-and-forward messaging, and automatic station announcements. JS8Call is heavily inspired by WSJT-X, Fldigi, and FSQCall.
What blows me away with this software is that I cannot hear any normal audio from signals over 12,000 km away in the USA and Europe, yet this software manages to pull the text through from conversations, and I can see that my signals are also being heard in Switzerland and the USA. In most cases stations are transmitting only 25W to 50W (many claim to be down as low as 5W).
But despite being able to have two-way or group text chats, the software also allows for messaging into an inbox. Two of the best features I think are the auto response (which means you can send queries to any station and if it has auto response enabled it will automatically reply with a signal strength, station info, status, or other standard responses) and the other feature is relays (where if I can contact station 2 who can contact station 3 but I can’t see stations 3, I can relay through station 2 to reach station 3 perhaps on a different continent).
Two useful resources to find out more are the guide at https://docs.google.com/document/d/159S4wqMUVdMA7qBgaSWmU-iDI4C9wd4CuWnetN68O9U/edit?usp=sharing and the map showing reception reports at https://pskreporter.info/pskmap.html.
Below is a screenshot of all the stations I picked up last night – I could see the contacts increasing once our midnight had passed and the USA had passed sunset (this time worked well for the 40m band on 7,078MHz).