Not sure if this helps, but we were evaluating Mattermost and are still evaluating Zulip at the moment. Our users pretty fast had a tendency towards Zulip, whil

Not sure if this helps, but we were evaluating Mattermost and are still evaluating Zulip at the moment. Our users pretty fast had a tendency towards Zulip, while I've had a slight preference for Mattermost from a ops view. We only have/had a short eval phase and our use case is a small raceengineering team with 40 people at the racetrack, independent of internet access. So a very particualar use case, and our needs might not cover you needs. Zulip pro * Threading model (can't value that high enough) * All messages overview, no matter what stream they were written in * Zulip community at chat.zulip.org with direct contact to the devs. Tim Abbott the lead dev helped me out in a issue with a user login (haven't used the Mattermost support so can't compare) Zulip con * Most ops work has to be done by a python script manage.py, API has room to improve Mattermost pro * API * haven't measured but the UI felt smoother, faster Mattermost con * you have to pay for Enterprise features Both have great docs and a docker deployment