I have been this last week. Very cool. I even built a keyboard for Sailfish OS.

XMPP for reliable, lightweight, & stable. SimpleX is a project worth keeping tabs on as well.

In practice Matrix isn’t decentralized in the slightest. Almost every account is on Matrix.org or a server they host. The whole protocol is a data/metadata syncing machine that isn’t good for privacy & is prohibitively expensive to run anything beyond a single-instance since all history of all users in all rooms necessarily needs to be synced onto the server. Many medium-sized servers have shutdown on storage costs & system resource requirements (especially RAM)—which forced its users often to flock back to Matrix.org. This is wild since it is mostly text chat.

Luckily there are actually decentralized chat alternatives with low system requirements to encourage self-hosting, but man is Matrix so overhyped & misunderstood.

My feeling is this is being written not just as a vent for ProcessOne adding a Matrix gateway to ejabberd but a warning to everyone thinking of setting up a trendy Matrix server or assuming enabling Matrix support will just be free. The eventual consistency model is expensive–for storage, for CPU/RAM, for client speed/sync–& everything it seems the Synapse & Dendrite servers are trying to do to speed it all up is in response of this likely fundamentally poor decision eventual consistency to ‘clone’ Slack/Telegram/Discord over allowing chat to be ephemeral & using forums for long-lived topics & Atom/RSS feeds for announcements.