Spam Trap

A spam trap is an address that exists only to catch senders who are not managing their lists properly. It is never used to sign up for anything, so any mail it receives is, by definition, mail you should not have sent. Hitting one tells inbox providers and blocklists that you are mailing addresses you did not collect with consent.

There are two main kinds. Pristine traps are addresses created purely as traps and seeded on the web. Recycled traps are formerly real addresses that were abandoned, hard-bounced for a long time, and then reactivated as traps — which is why mailing old, unengaged addresses is dangerous.

You cannot reliably "detect" a well-run spam trap from the outside, because it looks like a normal mailbox. The defense is list hygiene: only mail addresses you collected with permission, remove long-term bouncers, and prune unengaged contacts.