[falcolas]

Respectfully, I've only heard of one of those before, and none of them are installed on any of my devices.

Now, I looked up each of them, and found that they all rely on hosting your own server, or some kind of strictly limited "community" plan. The managed (and for Mattermost even self-hosted) servers all hide features (such as message history, rich moderation tools, or support tickets) behind a paywall.

These are solutions aimed at enterprises, and they use open source (or open core) licenses as the foot in the door. It's commendable that they offer to let you host the server yourself, but I would not call it "simple" to do so.

I believe that this high friction and low install base will make them effective non-starters in the open source development space.

[price]

> they all rely on hosting your own server, or some kind of strictly limited "community" plan

Happily this is not true of Zulip! Open-source projects get free hosting on zulipchat.com, with the exact same features as our corporate customers. Quoting from https://zulipchat.com/for/open-source/ :

> The hosting is supported by (and is identical to) zulipchat.com's commercial offerings. This offer extends to any community involved in supporting free and open source software: development projects, foundations, meetups, hackathons, conference committees, and more.

(I work on Zulip.)

[andrewshadura]

> The managed (and for Mattermost even self-hosted) servers all hide features (such as message history, rich moderation tools, or support tickets) behind a paywall.

I know nothing about the other systems but this isn't true for Mattermost. We run Mattermost ourselves and it does indeed offer message history and moderation tools, they're part of the open source Mattermost version. I can't think of any feature that I miss from it, to be honest.