List-Unsubscribe Header
The List-Unsubscribe header is an email header that provides email clients with a machine-readable way to offer one-click unsubscription directly from the inbox interface.
What Is List-Unsubscribe Header?
The List-Unsubscribe header is an invisible part of the email that tells email clients how to process unsubscribe requests without the subscriber needing to open the email and find the unsubscribe link. When implemented, email clients like Gmail show an 'Unsubscribe' button next to the sender's name in the inbox view. The header can specify a mailto: address (for email-based unsubscription) or a URL (for HTTP-based unsubscription). Google and Yahoo now require bulk senders to implement one-click List-Unsubscribe using the RFC 8058 standard, which adds a List-Unsubscribe-Post header for HTTP-based unsubscription.
Why It Matters for Newsletters
List-Unsubscribe is now required by major email providers for bulk senders. Without it, your emails may face filtering or reduced delivery. More importantly, inbox-level unsubscription gives subscribers an easy alternative to hitting the 'Report Spam' button, which is far more damaging to your sender reputation.
Best Practices
- Implement both mailto: and HTTPS unsubscribe methods in the header
- Add the List-Unsubscribe-Post header for one-click HTTP unsubscription
- Process header-based unsubscribes within seconds, not hours
- Test that inbox-level unsubscription works in Gmail, Yahoo, and Outlook
- Monitor unsubscribe sources to understand how subscribers prefer to opt out
How Aldus Handles This
Aldus automatically includes the List-Unsubscribe and List-Unsubscribe-Post headers in every newsletter, meeting Google and Yahoo's requirements. Unsubscribes from inbox-level buttons are processed instantly.