Threema is described as 'New mobile messaging app that puts security first. With true end-to-end encryption, you can rest assured that only you and the intended recipient can read your messages' and is a very popular instant messenger in the security & privacy category. There are more than 100 alternatives to Threema for a variety of platforms, including Android, iPhone, Windows, Mac and Linux apps. The best Threema alternative is Signal, which is both free and Open Source. Other great apps like Threema are Telegram, Element, Tox and SimpleX Chat.
ChatSecure is a free and open source messaging app that features OTR encryption over XMPP. You can connect to your existing accounts on Facebook or Google, create new accounts on public XMPP servers(including via Tor), or even connect to your own server for extra security.
Speek! is the first messenger that is anonymous and censorship-resistant by design. Speek! messenger encrypts all messages and is secure, private and decentralized.
SchildiChat is a Matrix client based on Element with a more traditional instant messaging experience.
VeilidChat is a 1-to-1, person-to-person text only chat application which serves as a technology demonstration for the Veilid application development framework. All communication is end to end encrypted, authenticated, private routed, and peer-to-peer. It's currently in early beta.
Quantum-resistant encrypted messaging, video/audio calls, and file transfers in the browser with optional registration and no downloads required.
0xchat is a secure chat app built on the Nostr protocol. It prioritizes security, featuring private key login, encrypted private chats and contacts, encrypted group chats.
2x your productivity with Struct, a brand-new real-time chat platform designed from the ground up around threads, feeds and AI.
TeleGuard is the data-secure messenger from Swisscows. TeleGuard encrypts every message and all telephone calls with encryption algorithm currently available: SALSA 20. TeleGuard servers are located in Switzerland, they are not subject to the data protection laws of the EU /...
Bitmessage is a P2P communications protocol used to send encrypted messages to another person or to many subscribers. It is decentralized and trustless, meaning that you need-not inherently trust any entities like root certificate authorities.
A fork of Signal for Android with proprietary Google binary blobs removed. Uses OpenStreetMap for maps and a websocket server connection, instead of Google Maps and Firebase Cloud Messaging.
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