Some top alternatives to Zulip includes mi.team, Slack, Glip, Google Chat and Discourse.
Yes, Zulip provides API.
Yes, Zulip provides a mobile app.
Zulip is located in Cambridge, Massachusetts
Zulip offers Freemium, Open-source, Subscription, Quotation Based pricing models
Yes, Zulip can integrate with Basecamp, Asana, Groove, Front and many more.You can find more integration for Zulip here
The starting price of Zulip is $6.67/User/Month