Svix is an open-source webhook service that handles event ingestion, signing, retries, and endpoint management with scalable delivery and client libraries.

3.4k stars273 forksMITlast commit Actively maintained
Managed Pub/Sub and WebSocket service providing channels, presence, and scalable fan‑out for building real-time features such as chat, notifications, collaboration cursors, and live updates; offered as hosted realtime infrastructure.
Svix is an open-source webhook service that handles event ingestion, signing, retries, and endpoint management with scalable delivery and client libraries.

3.4k stars273 forksMITlast commit Actively maintained
A protocol gateway that bridges users across different instant messaging networks using libpurple adapters, enabling cross-network chat and presence.

419 stars92 forkslast commit Slowing down
Scalable, modular XMPP/Jabber server written in Java supporting TCP, BOSH, WebSockets, federation, components, HTTP API and push notifications.

359 stars110 forksAGPL-3.0last commit Actively maintained
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. 2 of 3 shipped a commit in the last six months. Licences in this list: MIT, AGPL-3.0. In exchange you take on hosting, backups and updates yourself.
Browse everything in Messaging & Event Streaming (Brokers/Queues).