AltME is described as 'The world's most powerful lightweight collaboration system' and is a Group Chat App in the Office & Productivity category. There are four alternatives to AltME for a variety of platforms, including Android, iPhone, Online / Web-based, Self-Hosted solutions and Windows. Most alternatives are Group Chat App and Todo List Managers. The best alternative is Element, which is both free and Open Source. Other great apps like AltME are Zulip (Free Personal, Open Source), Conduit Chat Server (Free, Open Source) and Dust (Free).
Element is a secure collaboration and messaging app based on the Matrix protocol. It’s decentralised to deliver digital sovereignty, and based on an open standard for easy connections and interoperability. It is end-to-end encrypted by default.