One-click unsubscribe

One-click unsubscribe is a pair of email headers, List-Unsubscribe and List-Unsubscribe-Post, that let a mailbox provider show an opt-out control at the top of a message and process it without the recipient visiting a landing page. Gmail and Yahoo require it from bulk senders, and the request must be honoured within two days. An easy unsubscribe costs far less than a spam complaint, so do not put a confirmation step or a preference page behind it.