List-unsubscribes in email headers
Allow users to unsubscribe with just a couple of clicks.
List-Unsubscribe is an email header that allows recipients to easily opt out of marketing emails. It provides an additional unsubscribe method directly from their email client, such as Gmail, without having to search for an unsubscribe link within the email body.
When an email includes a List-Unsubscribe header, email providers like Gmail and Outlook display an unsubscribe option in a prominent location, making it easy for users to manage their subscriptions. This means that in some cases email recipients can unsubscribe without even opening an email.
How List-Unsubscribe Appears in Gmail
When an email includes a List-Unsubscribe header, Gmail may display an “Unsubscribe” link next to the sender’s name at the top of the email. Clicking this link allows users to unsubscribe with just a couple of clicks.

You can see unsubscribe button on the header of the email next to sender name
Better User Experience: It makes opting out of unwanted emails easier and reduces frustration.
Improves Deliverability: Emails that comply with List-Unsubscribe are less likely to be marked as spam, improving sender reputation.
Industry Best Practice: Many email marketing platforms and anti-spam regulations encourage or require List-Unsubscribe implementation.