Briar

Session

Session is a private messaging app built and operated by a global community of privacy experts. It uses Account IDs instead of phone numbers or email addresses for signup, encrypts every message with the Session Protocol (built on libsodium), and routes conversations through onion-routed paths across thousands of community-run nodes so no single server can see both the sender and recipient of a message.

Jami

Jami is a free, open-source communication platform backed by the Free Software Foundation as a GNU project. It provides instant messaging, audio/video calls, group chats, video conferencing, and screen sharing, all built on a fully peer-to-peer architecture that doesn't rely on central servers to relay communication. Because Jami is serverless and end-to-end encrypted with perfect forward secrecy, it requires no personal information to create an account and can even work over a local network without internet access. It's available on Linux, Windows, macOS, iOS, Android, and Android TV, and includes an extension platform and SIP client support for added flexibility.

Tox (qTox)

Tox is an open, peer-to-peer messaging protocol built to let people communicate without anyone else listening in, and without relying on centralized servers that could be compromised or monitored. Official and community clients built on the protocol - including qTox for desktop, Toxic for Linux terminals, and aTox for Android - provide encrypted instant messaging, voice and video calls, screen sharing, and file transfers with no artificial size limits. Tox is completely free and comes with no advertising, ever, and is developed openly by its user community rather than a company. Its distributed network architecture means there is no central point of failure or control, and both the protocol and its libraries are free and open source.

SimpleX Chat

SimpleX Chat is an open-source, end-to-end encrypted messenger built around a network design with no persistent user identifiers of any kind, not even random ones. Messages are relayed through servers that see only noise, so there is no phone number, username, or account ID for anyone, including SimpleX, to tie back to a person. The app supports one-to-one and group chats, audio and video calls, file transfer, and multiple chat profiles, and it can run on self-hosted servers for organizations that want full control over their infrastructure. Its protocol and clients are fully open source and have been independently security-audited by Trail of Bits.