Spectrum 2
Spectrum 2 is an open source instant messaging transport. It allows users to chat together even when they are using different IM networks.
Homepage
Source code
Other self-hosted communication - custom communication systems
Realtime server for reliable two-way communication over WebSockets, Server-sent events, etc.
Apprise allows you to send a notification to almost all of the most popular notification services available to us today such as: Telegram, Discord, Slack, Amazon SNS, Gotify, etc.
Language-agnostic real-time messaging (Websocket or SockJS) server.
Peer-to-peer chat app that is serverless, decentralized, and ephemeral.
A simple, fast, and reliable chat server powered by Matrix.
Community-driven Matrix homeserver, the continuation of conduwuit focusing on user experience and new features (fork of Conduit).
Federated, end-to-end encrypted messaging service for the web, iOS, and Android, supporting text, photos, video, and WebRTC video and audio calls.
Fully-featured Matrix client for Web, iOS & Android.
Whistleblowing software enabling anyone to easily set up and maintain a secure reporting platform.
Software framework for decentralized, peer-to-peer networking.
Notification server with Android and CLI clients (alternative to PushBullet).
Anonymously share files, browse and publish _freesites_ (web sites accessible only through Hyphanet) and chat on forums.
Run it with Docker
Spin up Spectrum 2 on a VPS in minutes. Use the docker-compose generator to get a starter snippet, or grab a server below.