@mntmn @bleeptrack sadly you probably cannot build a plugin for a receiving mail server because it would break DKIM signatures. The outgoing server however could add stamps and the mail client then has to render the postmark depending on the mail header. But that would be complicated because it touches so many software projects. I think a client only solution would be the easiest (or you do the spam processing and afterwards deliberately remove the DKIM signature on the receiving server)
Now i want this 🙂 it’s such a neat idea to bring back some of the “old days”. I remember decorating the envelopes was a thing too that’s completely gone with electronic equivalents too.
@bleeptrack client seems like a good place, maybe mailservers can be allowed to add to the stamp. Would this be a generative thing based on string(s) in the header? That would be cool, like the 'received' header, it can be multiple and each adds to it. Hmm, could also use the 'received' header as a stamp modifier.
sending client inserts initial stamp string, receiving client generates stamp based on initial stamp string + all 'received' headers.
The stamps on a received mail should get semi-transparant post marks for each hop from the respective server. Could be generated from the mail header info.
@bleeptrack How about instead of payment stamps adding a "received stamp". There's already a Received: header for every server that touched your e-mail (at least in theory).
You can always add a Comment: header, but it's meant to be human readable text - so there might be other comments in place already and your plugin has to identify the one with an embedded stamp.
Edit: having an online tool to decode your header if someone has a different client/webui would also be useful.
@bleeptrack I just found a 10 year old (hand written) post card that I forgot to send. I was surprised that the price has doubled in that time. 🤯
but also that gave me the opportunity to add two more beautiful stamps on it. ✨
@bleeptrack How about both, a higher fee for the megabytes plus the airmail extra counterpart for avian carrier?