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Glossary · Published 2026-09-29 · AgentiSend team

List-Unsubscribe

List-Unsubscribe: The header a mailbox shows as unsubscribe. Topic sends and broadcasts carry one.

List-Unsubscribe is one or two links in angle brackets, an https link and a mailto link. List-Unsubscribe-Post is the one-click companion, and only next to an https link. You can set both on a send whose From is a domain you have verified here.

A send with a topic_id, and every broadcast, already carries a pair that records the click as a topic opt-out or a suppression. Do not add a second pair that points somewhere else on those sends.

Related terms

  • Topic — A named kind of mail. A contact who opts out of it is skipped on sends of that kind.
  • Suppression — An address we will not mail. A later send to it is refused.