What is RFC 8058?

RFC 8058 defines the standard for one click unsubscribe functionality in email. Published in 2017, this specification establishes how List-Unsubscribe and List-Unsubscribe-Post headers should work to enable single click unsubscription directly from email clients.

The RFC specifies that senders include a List-Unsubscribe-Post header containing "List-Unsubscribe=One-Click" to signal support for POST based unsubscription. When present, mailbox providers can send an HTTP POST request to unsubscribe users without requiring them to visit a webpage.

Gmail and Yahoo's 2024 requirements effectively mandate RFC 8058 compliance for marketing messages. The standard that was optional for years became required as major providers enforced it to improve user experience and reduce complaint rates.