Is one-click unsubscribe required by Gmail/Yahoo?

Yes, one click unsubscribe via List-Unsubscribe headers is required by Gmail and Yahoo for bulk senders of marketing and promotional messages. The requirement became mandatory as part of their 2024 bulk sender guidelines.

The requirement specifically applies to marketing messages. Transactional emails (order confirmations, password resets, account notifications) are not subject to the same requirement, though including unsubscribe options in transactional mail is still good practice.

Implementation requires both the List-Unsubscribe header (with a valid HTTPS URL) and List-Unsubscribe-Post header to enable true one click functionality. Most modern ESPs have implemented this functionality, but self managed sending infrastructure may require updates to comply.