Platforms
- Android
- iPhone
- Android Tablet
- iPad
- F-Droid
United States



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 bitchat.



monocles chat is a fork of blabber.im and Conversations with some changes, to improve usability.



Real-time chat platform structured with threads, custom feeds, project tagging, and AI moderation. Provides privacy controls, instant file and code sharing, multiple viewing modes, moderator tools, light/dark modes, and unifies collaboration for organizations and communities.

Open source Jabber (XMPP) client with multi-account support, clean and simple interface. Being both free (as in freedom!) and ad-free, Xabber is designed to be the best Jabber client for Android .



ROOM-39 is a privacy-preserving, security-focused social platform built on a zero-knowledge architecture. Unlike standard messengers, ROOM-39 is designed under the principle that privacy is enforced by mathematics, not trust.




Fully open source instant messaging server and clients. No proprietary components or non-free dependencies. Backend in pure Go (GPL 3.0), with a command-line administration tool in python + gRPC. Clients for Android, iPhone, and Web - ReactJS (all licensed under Apache 2.0).




GoldBug is a secure Instant Messenger. You can be sure with using GoldBug (GB), that no third party can look into your chat communication. Private user-to-user communication remains private. GoldBug therefore uses strong multi-encryption with different layers of modern...




SureSpot is an open source encrypted messenger designed to make encrypted messaging simple and accessible to anyone.









Fully end-to-end encrypted business collaboration platform that is the only on the market supporting E2EE HD video conference up to 100 participants.



At this point in the digital world, our personal digital metadata – not just our messages, but data about who talks to whom, when, and where – has been marketed, auctioned, and monetized hundreds of thousands of times over.


