Matrix as a protocol and any of the clients that use it. SchildiChat and Element being two.

In theory you could even make that interoperable with WhatsApp i( in the EU) since the DMA makes that mandatory, I am not aware if anyone who did it though.

https://developers.facebook.com/m/messaging-interoperability...

I used to run a matrix instance years ago. I remember the account setup being super difficult for my family members. And the client was so basic. Is it different nowadays?

yes; matrix has improved significantly - eg Element X is an unrecognisable improvement over the old Element app.

SimpleX has end-to-end encryption, fancy mobile clients, and does let you host your own server:

https://simplex.chat/docs/server.html

Does SimpleX even sync messages between the phone and the desktop? Last time I checked they didn't unless you were maybe on the same network

Depends on what you mean by sync. It has limited support for tethering a mobile device to a computer on the same LAN, but lacks the kind of independent multi-device support that's a available in e.g. Matrix.

That sounds like difficult UX. Especially when WhatsApp just works

When “just works” means “lacks real security”, I’d rather have something experimental.

They don't, and I think they argue it's a security feature.

It is, at least, intentionally designed that way, for better or worse.

You can get per-conversation sync by joining multiple clients to the conversation.

It's one of those things where you'd probably want to be less secure and always sync to all devices.

Matrix comes to mind (Synapse server and whichever client you choose). It has good encryption and can be federated. Downside is that it gets heavy for old devices when you're in a lot of encrypted group chats.

XMPP is very efficient and delightfully simple to use and administrate. I never tried E2EC with it, but there are options on the clients, like OMEMO. It has limited federation.

The simplest server IMO is Openfire, but offers range from Lua-written Prosody to the extremely expensive Isode servers that can do complete federation, HF radio XMPP and probably coffee and pizzas too.

I used to run a matrix instance years ago. I remember the account setup being super difficult for my family members. And the client was so basic. Is it different nowadays?

Omemo I heard of. from what I read it’s a solid alternative to Signal’s protocol. Is it easy to use? Is there something we can just run the server, spin up some users and have them easily dm each other?

ejabberd is a battle-tested XMPP server and they recently added a native Matrix protocol bridge module. So supposedly now you can have your users connecting over both networks seamlessly. Yet to actually try that.

https:/matrix.org