Open-source, decentralized messaging network built on a Haskell core with Kotlin Multiplatform and native iOS clients; end-to-end encrypted messaging without user IDs.
19.3k stars1.4k forksAGPL-3.0last commit Actively maintained
8 self-hosted Threema alternatives
End-to-end encrypted instant messaging service providing secure one-to-one and group chats, voice and video calls, and file sharing. Offers a managed business edition with an admin console (Threema Work) and an on-premises deployment option for data sovereignty.
Alternatives to Threema
#2
Tinode is an open source instant messaging platform with a Go backend, web/mobile clients, JSON WebSocket and gRPC APIs, and support for one-to-one and group chat.
13.5k stars2.1k forksGPL-3.0last commit Actively maintained
#3
Synapse is a Matrix homeserver implementation for running federated, secure real-time chat and collaboration on your own infrastructure.
4.6k stars587 forksAGPL-3.0last commit Actively maintained
#4
Tox is a decentralized, peer-to-peer communication system for encrypted messaging, voice/video calls, screen sharing, and file transfers without central servers.
2.7k stars311 forksGPL-3.0last commit Actively maintained
#5
Self-hosted, lightweight federated messenger with end-to-end encrypted threads and optional WebRTC audio/video calling across independently hosted nodes.
1.5k stars96 forksApache-2.0last commit Actively maintained
#6
Self-hosted, open-source XMPP-based messaging server providing end-to-end encryption, multi-device sync, federation, secure backups, and integrated WebRTC audio/video calling.
447 stars51 forksApache-2.0last commit Actively maintained
#7
SAMA is a Node.js-based open-source chat server using uWebSockets.js, MongoDB and Redis, providing WebSocket/HTTP APIs, E2EE, clustering, and web/mobile clients.
158 stars15 forksGPL-3.0last commit Actively maintained
#8
Jami is a distributed communication platform for private messaging, audio/video calls, and conferencing, designed to work without central servers and with end-to-end encryption.
Activity unknown
What replacing Threema actually involves
Every option on this page is open source and free to run on your own hardware, so you own the data and there is no subscription to cancel. 7 of 8 shipped a commit in the last six months. Licences in this list: AGPL-3.0, GPL-3.0, Apache-2.0. In exchange you take on hosting, backups and updates yourself.
Browse everything in Team Chat & Messaging.
