Quiet is an alternative to team chat apps like Slack, Discord, and Element that does not require trusting a central server or running one's own. In Quiet, all data syncs directly between a team's devices over Tor with no server required.
Quiet is written (mostly) in TypeScript, with Electron and React Native frontends.
While apps like Slack, Discord, and Signal use central servers, Quiet syncs messages directly between a team's devices, over Tor, with no server required.
Each group of people (Quiet calls them "communities") gets their own insular network, so that data from one community never touches the devices of Quiet users in other communities. Not even in encrypted form!
Message syncing is taken care of by a project called OrbitDB, which works like a mashup of Git, a gossip protocol, and BitTorrent; it broadcasts new messages, syncs the latest messages, and fetches files. Syncing means that users typically receive all messages sent while they were offline.