[luplex]

This is the mission of element: https://ems.element.io/get-started?pk_vid=437a8cb738dee05a16...

They host a matrix.org server (Synapse) and a web client frontend (Element) on any domain. If you want to, you can also just host it yourself later.

Element is very good these days!

[pmontra]

Thanks. Looking at that registration form it seems that the domain to pick is actually a 3rd level domain, always ending in element.io.

Another requirement of my list would be "Use your own domain". That would increase portability. I didn't think about it.