SimpleX Chat

SimpleX Chat is a messenger with no user identifiers: no phone number, email or username is required, and each new contact relationship generates a pair of one-time message queue addresses, so conversations with different people share no metadata linking them to one person. Messages sit briefly on relay servers and are deleted on delivery, servers do not talk to each other, and no account records are kept. Transport uses the in-house SimpleX protocol with end-to-end encryption and a double ratchet, and Tor connections are supported.

It addresses metadata exposure rather than content encryption alone. Clients are open source and the code has been audited by Trail of Bits, with text, voice, files, disappearing messages and group chat supported; because there is no unified identity, moving to a new device means re-establishing contacts.