https://github.com/dtonon/outis

Outis fights spam generating and sending a fake "user unknown" bounce for an email you received, so the sender believes your address does not exist.

Of course this isn't a novel idea, I created a similar program back in 1998–1999 (actually, with a slightly different purpose), but I decided to revive it because it should work quite well with the recent trend of automated emails generated by AI, where the sender might expect a reply; it helps remove your email address from their list.

I don't have strong evidence about its effectiveness, but I'm testing it for few weeks and the spam noise seems to be reduced; I don't receive similar or followup emails any more.

Any idea on how to improve it? :)