One-click unsubscribe

One-click unsubscribe is a standard, defined in RFC 8058, for unsubscribing directly from the mail client. The sender includes two headers: List-Unsubscribe with an https URL, and List-Unsubscribe-Post with the value List-Unsubscribe=One-Click. When the reader presses the Unsubscribe button that Gmail or another client shows, the client sends an HTTP POST to that URL, and the sender’s system removes the address at once. The link works on the first click, with no landing page, confirmation step or login.

It matters because major mailbox providers now require it from senders of bulk mail, and treat its absence as a mark against the domain. It also changes reader behaviour in your favour: a person who can leave in one press is far less likely to press “report spam” instead, and a spam complaint costs your reputation much more than a lost address. For cold email under legitimate interest, honouring objection immediately is part of what makes the basis defensible, and one-click is the most immediate form there is.

Seegnals adds the RFC 8058 headers plus a visible unsubscribe link to every message. An unsubscribe puts the address on your suppression list, stops the sequence for that person, and shows in campaign stats as Opted out.