SimpleX Chat

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.

Delta Chat

Delta Chat is a free, open-source messaging app that delivers end-to-end encrypted chats over the existing email network instead of a proprietary server infrastructure. Any two Delta Chat users can message each other using just an email address, with the app handling the IMAP/SMTP plumbing invisibly in the background so it feels like a normal chat app. The project also runs dedicated "chatmail" relay servers for people who want an account without an existing email address, and supports multi-device sync, audited end-to-end encryption, and small in-chat web apps (webxdc) for games and simple tools. Because it rides on open Internet standards rather than a single company's servers, no account can be shut down by one vendor and the core client is developed in the open on GitHub.

Briar

Briar is a free, open-source messaging and forums app designed for situations where regular internet access is unreliable or censored. It connects directly with nearby contacts over Bluetooth or Wi-Fi, or routes messages through the Tor network when online, storing all data locally on the device rather than in the cloud. Briar started as an Android-focused app and now also has a Briar Desktop beta for Windows, macOS, and Linux. In mid-2026 the project announced it has entered maintenance mode, meaning it will continue receiving bug and security fixes but is not planned to get major new features, due to funding constraints and long-standing technical challenges like Android battery drain.

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.