We regularly run it with 40-50 users, and it's fine... as long as you limit the number of displayed video streams to 12-15 or fewer. This tends to happen organically with people muting video, or otherwise you can configure Jitsi to limit it to show video for the last 12 people who spoke.
Otherwise you risk overloading people on devices which can't render >12 simultaneous video streams without melting. You can push the limit higher if you know everyone is on a fast machine however.
One thing worth noting is that if a one or more user connects via Firefox then quality degrades for everyone - but fixes for this look to be in flight over at https://github.com/jitsi/jitsi-meet/issues/4758
What server resources to you need for those 40-50 users with Jitsi/Matrix? I haven't seen estimates of required resources when I've looked, but I assume there's some doc somewhere.
(Thanks for the good work.)
Roughly speaking we're seeing Jitsi serve around 1000 concurrent streams (i.e. 25x 50-user conferences) on a typical 4 core box with 8GB of RAM. However, it's worth noting that Jitsi is pretty low resource - all it's doing is forwarding streams of data around the place. All the heavy lifting is done by the clients when displaying all the concurrent videos, so it's the clients which tend to be the bottleneck.
Otherwise you risk overloading people on devices which can't render >12 simultaneous video streams without melting. You can push the limit higher if you know everyone is on a fast machine however.
One thing worth noting is that if a one or more user connects via Firefox then quality degrades for everyone - but fixes for this look to be in flight over at https://github.com/jitsi/jitsi-meet/issues/4758