matrix

Element is a secure and decentralized communication client for the Matrix network. It provides end-to-end encrypted messaging, voice/video calls, file sharing, and collaboration features with a focus on privacy and security.

Synapse is the reference homeserver implementation for Matrix, an open standard for secure, decentralized, real-time communication across different service providers.

PushBits is an open-source relay server for push notifications that delivers important notifications through Matrix, offering a self-hosted alternative to Pushover and Gotify without requiring an additional app.