Lots of corps use discord, but at an alliance level you'll often end up with mumble for comms. Another 'dead' open source software that's used is Jabber (XMPP)

Lots of corps use discord, but at an alliance level you'll often end up with mumble for comms. Another 'dead' open source software that's used is Jabber (XMPP) for 'pings' aka broadcasts to tell people there's a fleet up.