Whenever we see changes in the world of deliverability and compliance, we want to make sure people are aware of it. Recently, some changes were made to List-Unsubscribe features, and we thought it was a great opportunity to re-visit the subject.

List-unsubscribe is an x-header that allows end-recipients the ability to be removed from a mailing list without clicking the unsubscribe link or hitting the spam/junk button. It was created so consumers who were scared of clicking the unsubscribe link would have an alternate way to opt-out of receiving email that wouldn’t affect the senders reputation.

List-unsubscribe is used by Gmail and Microsoft, and both mailbox providers handle the functionality a little differently. Senders are able to use two versions of list-unsubscribe:

  • mailto: This version emails the unsubscribe to a specified email address
  • http: This version utilizes a URI to complete the unsubscribe


Gmail has stated that using list-unsubscribe was a best practice. Only senders with good reputations will see the functionality, however, they want all senders to implement it. Gmail has said they prefer the mailto: vs. the http: version (though, the http: version is still accepted).

Since that time, they have rolled out “Easy Unsubscribe,” which is not based on list-unsubscribe. We are unaware of how Easy Unsubscribe affects list-unsubscribe at Gmail at the moment, but you can learn more about it and its functionality in our blog, Is Gmail’s “Easy Unsubscribe” a Business Killer for Marketers?.


Similar to Gmail, Microsoft also requires senders to have a good reputation to have list-unsubscribe enabled. Microsoft recently announced that they will only honor the mailto: version of list-unsubscribe and any links will be ignored.

What does this mean to you?

We recommend that SendGrid customers implement list-unsubscribe. If a sender is using our subscription tracking, both the mailto: and http: versions will be inserted into the header of messages they send. If subscription tracking is not being used, they will need to make sure both are added in order to benefit from the list-unsubscribe feature.

If you’re unsure of how to implement list-unsubscribe with your SendGrid account, you can contact SendGrid Support any time to receive assistance with your account.

Learn more about best practices for unsubscribee and list management here.

Tanya is SendGrid's Email Deliverability Consultant.