Thanks for all your advice. Here's a report on my experiences for anybody that may have a similar question. I demo'd Zulip with Jitsi, Jami, and Nextcloud Talk today.

I've actually used Signal desktop for years, and love it, but don't really want to mix work with personal, and if I didn't already use it, I'd squirm about the required mobile app on my personal phone. Telegram might be a little easier that way-- I don't think you have to have an app to make an account, just a phone number.

I liked Zulip, but I didn't like Jitsi. It required a google account or a github account to host a meeting, it ran in browser instead of embedded in the Zulip app somehow, and the Jitsi desktop app seemed to be from 2003.

Jami was ok. I was able to set it up pretty easily, but I didn't know if others in the org can handle that it's P2P so you can't leave messages for others off hours. Also there seemed to be a lot of complaints about its reliability in its own forum.

NextCloud talk on the free servers didn't really work. I could get voice and text, but screen sharing just errored. I think I'd have to set up a TURN server or something like that. So if that requires hosting anyway, might as well do Matrix. Also the free servers were really slow.

So next test for me is Matrix. Is there a way I can try it out for free to see if I can recommend it to the rest of the company? Without spending hours on it? I've probably wasted more company time on this project than I would've saved in subscriptions.

I don't see privacy listed in your requirements so I'm not sure why you've posted here. Self hosting would be necessary for that in any case.

Teams would probably be the best option given your requirements. It does everything, and for the most part it just works. Sometimes it doesn't, but when that happens, you've got entire departments at Microsoft working to fix it, as opposed to when a local service you're at the mercy of the one guy who knows a bit about computers (or worse, his nephew).

Mattermost, wire, jitsi, Zulip

I'm in the same predicament here. What industry are you in? You might want to look into your regulatory requirements.

My current top pick is Nextcloud Talk.

• Element Matrix doesn't support small business if you are not selfhosting
• Mattermost has no Group Callings
• Nextcloud Talk has all the features Skype had and additionally everything else that Nextcloud has to offer.
• Teams is a nightmare, ask any sys admin. And looking at how MS plans to add Ads to the free version fo office they likely will do the same for Teams
• Discord is a privacy Nightmare
• Google Meet is... well makes you once again dependent on a US Company
• Signal really just has a shit desktop application. Due to their security focus only very few messages can load from your phone
• Telegram is not a secure service
• Jami I actually need to check out 🤔