@andstatus @verius @thefaico Yeah, so, if we have that, and the messages have UIDs we know are unique, we can use that as a means of helping detect and suppress duplication.  What I'd like to do is have the server send a challenge if the message sent to the API is duplicated, like "we already have a message by this user with exactly that contents in message <uid>, did you mean to send it again?" and the client could then act based upon that.