As standard, the platform automatically adds the List-Unsubscribe header to all marketing emails. You don't need to configure or add it yourself.
For example, in iOS, recipients may see a banner at the top of the email that says:
This message is from a mailing list.
Unsubscribe
List-Unsubscribe applies only to marketing emails. Transactional emails sent from the platform do not include the List-Unsubscribe header because they are not subscription-based communications.
Benefits of List-Unsubscribe
It makes it easier for recipients to leave your mailing list if they wish to, as the unsubscribe option is more prominent in the header as opposed to being buried away in the body of the email.
By making unsubscribing easier, List-Unsubscribe helps recipients opt out of content they no longer want instead of marking messages as spam. This can help protect sender reputation and improve long-term email deliverability.
Will List-Unsubscribe increase unsubscribe rates?
The aim of the button is to stop complaints, and if you’re getting complaints then you need to ask yourself why that might be:
Is your content poor and irrelevant?
Are your sends badly timed?
Are you sending to bad data, such as purchased contacts or very old subscribers?
If you answer yes to any of those questions then you're probably at risk of losing people, but that’s not necessarily a bad thing. Understanding why recipients unsubscribe or complain is more valuable than simply retaining them, and the unsubscribe process can help provide that insight. It's better to lose the people who risk ruining your reputation and focus on those who want to hear from you.
If you're collecting and using good data (which you should be doing), and your email content is timely and relevant, then having an unsubscribe option at the top won't affect anything.
Can I customise List-Unsubscribe?
You can't customise it in any way or redirect to your preference centre.
Email clients detect the List-Unsubscribe header and decide how, or whether, to display it. The appearance and behaviour are controlled by the email client, not by the sender.
Why can't I see the unsubscribe option?
There are two reasons for this:
Support of List-Unsubscribe varies across email clients, so it may be the case that the email client you've tested with doesn't support List-Unsubscribe at all.
Email clients may only display List-Unsubscribe for senders that are considered to have a strong sending reputation, otherwise, it won't be shown.