but that depends on the vendor. highest chance to do it is with Monero, even considering that basically no one knows it

no, it isn’t for

• matrix, because if the servers ever connect again, the message will get through. this is what’s called an “eventually consistent” system
• any mainstream and semi-mainstream messengers, where there is a single server (from the users’ point of view), and the message just can’t get lost (randomly)

the client shouldn’t be dealing with issues between servers. that’s the servers responsibility. if the server has told the client that it got the message, what is there anymore for the client to do?

The issue with AP objects not making it to other clients / servers is more about federation discovery.

I don’t think so. if you know the recipient, you know it’s servername too. and then your server can forward it to theirs.

I think the problem here is that messages are not always delivered.

AP would actually work fairly well as a messaging protocol

except when a temporary disruption in the connection results in new posts/comments/etc to not get delivered

github is not just about git though.