#Ricochet is a #decentralized instant messenger, meaning there is no server to connect to and share #metadata with. Further, using #Tor, Ricochet starts a Tor hidden service locally on a person's computer and can communicate only with other Ricochet users who are also running their own Ricochet-created Tor hidden services. This way, Ricochet communication never leaves the Tor network.

https://en.wikipedia.org/wiki/Ricochet_%28software%29