What is List-Unsubscribe header?
The List-Unsubscribe header is a line of hidden code in a marketing email that lets mailbox apps show their own unsubscribe link or button near the sender name.
Instead of hunting for a footer link, the reader sees an option in the inbox interface. It can use a web link, a mailto address, or both. The one-click version lets a person leave with a single action and no extra page.
This matters because a frustrated reader who cannot find an unsubscribe link tends to hit the spam button instead. A visible, honoured option turns would-be complaints into quiet opt-outs, which are much less harmful to reputation.
Most email platforms add the header for you, but it is worth checking in a test message. Whatever the header does, the request must be honoured quickly and the contact suppressed.
A worked example.
A hypothetical clothing store views the source of a test email and sees that the header is present. It sends the message to a Gmail test account and confirms that an unsubscribe option appears beside the sender name. It also checks that a test opt-out removes the address from later sends.
Common mistakes.
- Assuming the header exists without checking a real message
- Leaving a request unprocessed so the person keeps getting emails
- Removing the footer link because the header is present
Want this handled for your store? See our email deliverability service or book a free audit.
Find out what your list is actually worth.
We review your flows, list health, authentication records and last ninety days of performance, then send back what we found.
30 minutes, no obligation, and the findings are yours to keep either way.