Novu is an open-source notifications platform with a unified API, workflow orchestration, and embeddable in-app inbox for email, SMS, push, and chat.

39.7k stars4.4k forkslast commit Actively maintained

Sendbird is a communications API platform offering SDKs and APIs to add in-app chat, group channels, messaging, and real-time voice/video to web and mobile apps, plus moderation tools, analytics, and managed cloud messaging infrastructure.
Novu is an open-source notifications platform with a unified API, workflow orchestration, and embeddable in-app inbox for email, SMS, push, and chat.

39.7k stars4.4k forkslast commit Actively maintained
Tinode is an open source instant messaging platform with a Go backend, web/mobile clients, JSON WebSocket and gRPC APIs, and support for one-to-one and group chat.

13.5k stars2.1k forksGPL-3.0last commit Actively maintained
ejabberd is an Erlang/OTP-based messaging server providing XMPP chat and presence, MQTT broker capabilities for IoT, and SIP services for real-time communications.

6.7k stars1.5k forkslast commit Actively maintained
Synapse is a Matrix homeserver implementation for running federated, secure real-time chat and collaboration on your own infrastructure.

4.6k stars587 forksAGPL-3.0last commit Actively maintained
Openfire is an open source XMPP (Jabber) server for real-time messaging and collaboration, with a web admin console and a plugin ecosystem.

3.1k stars1.4k forksApache-2.0last commit Actively maintained
Stoat (formerly Revolt) is an open-source chat platform for communities and teams with channels, direct messages, roles/permissions, moderation tools, and bot support.

2.6k stars296 forksAGPL-3.0last commit Actively maintained
SAMA is a Node.js-based open-source chat server using uWebSockets.js, MongoDB and Redis, providing WebSocket/HTTP APIs, E2EE, clustering, and web/mobile clients.

158 stars15 forksGPL-3.0last commit Actively maintained
Salut à Toi (SàT) is a self-hostable, XMPP-based communication suite with web, desktop, and CLI frontends, supporting chat and collaborative features via plugins.

Activity unknown
Libervia is a modular XMPP-based communication suite offering chat, microblogging, file sharing, and other social features across web, desktop, and CLI interfaces.

Activity unknown
Every option on this page is open source and free to run on your own hardware, so you own the data and there is no subscription to cancel. 7 of 9 shipped a commit in the last six months. Licences in this list: GPL-3.0, AGPL-3.0, Apache-2.0. In exchange you take on hosting, backups and updates yourself.
Browse everything in Team Chat & Messaging.