List-Unsubscribe Header

A hidden email header that lets mailbox providers show a built-in unsubscribe button, giving recipients an alternative to marking mail as spam.

By Brandon MinaCEO, BrandPilot AIUpdated November 2026

Short answer

The List-Unsubscribe header is a hidden email header that lets mailbox providers show a built-in unsubscribe button, giving recipients an alternative to marking mail as spam. It can point to a mailto address or a web link. Gmail and Yahoo require bulk senders to support it, including the one-click version.