Zulip is a powerful, open source group chat application that combines the immediacy of real-time chat with the productivity benefits of threaded conversations.
The fully threaded model of Zulip allows you to follow conversations that you care about and ignore the ones you don't.Cons:
Nothing I can think about. It's insanely great :)
Zulip is built by keeping productivity in mind. Each conversation in Zulip has a topic. This allows you to take part in more than one conversation at the same time. This also make catching up on conversations efficient as compared to cSlack, Mattermost etc where you have to scroll through hundreds or thousands of messages to figure out what is going on. Zulip is the most active open source chat application in GitHub and has 350+ contributors from all across the world.Vishnu Ks has used this product for one year.
Open source, chat based on topic, lots of integrationsCons:
Sorry, can't able to find.
Zulip chat is awesome.
It's best alternative for Slack, Mattermost, Hipchat and other group chat apps.
It has amazing search feature with lots of operators.
know more features at https://zulipchat.com/features/Vishwesh Jainkuniya has used this product for one year.