If you care abt privacy you could just wait till someone is online to send the outbox content.

You dont need asynchronous messages to be stored centrally, but you d need both to be online at the same time at some point.

That s a feature I never saw in a chat app, they always have a central crap keeping messages defeating any kind of serverless claim.

What if I have a friend who, due to timezones, is never online when I am. Or very rarely. Seems a bit ignorant of the wider needs of an internet community to not allow people to talk if they don't share enough of a timezone.

I supposed I'm (and you seem to be) implying that in the scenario of a group made up of A, B and C, if A and C are online when A sends a message (and then A goes offline) then B can receive A's message forwarded by C. We wouldn't need a server in this case, would we?

I do want to point out that it is possible to use a central server while keeping metadata private if you use noise

How do you mean? Could you link to where you could find that? Because I searched for 'metadata' in the Noise Protocol repository and came up with nothing (https://github.com/noiseprotocol/noise_wiki/search?q=metadat...) N.b. I am very much an amateur and am fascinated by private communication methods

The Noise Protocol is a specific project, that, funnily enough, doesn’t include generating noise. I believe the name is intended to mean that the messages look like noise.

Here are some protocols that use noise (specifically differentially private noise):

https://vuvuzela.io/research

https://people.csail.mit.edu/nickolai/papers/tyagi-stadium-e...