Riot : Riot allows teams to communicate across a wide range of collaboration apps. If some team members use Riot while others use IRC, Slack or Gitter, Riot ...
Zulip : Powerful slack-like open source group chat
Novu : The open-source notifications infrastructure. A fully-featured microservice to send SMS, E-mail, Slack and Push notifications. Embeddable notification...
HedgeDoc : HedgeDoc (formerly known as CodiMD) is an open-source, web-based, self-hosted, collaborative markdown editor.
You can use it to easily collaborate on ...
Zulip : Zulip is a powerful, open source group chat application that combines the immediacy of real-time chat with the productivity benefits of threaded conve...
Mattermost is a self-hosted solution for bringing all your team communication to one place, and making it searchable and accessible anywhere