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List-Unsubscribe headers

In February 2024, Yahoo and Gmail began tightening email rules with Dmarc and Dkim requirements.
In June 2024, there will also be a stricter focus on List-Unsubscribe headers. List-Unsubscribe headers are not new. Marketing emails were already requested to contain these headers. The change is that Yahoo and Gmail will be checking for the presence of there headers more strictly. In this article we will discuss the following topics:

What is a List-Unsubscribe header?

List-Unsubscribe headers make it easy for email recipients to unsubscribe from mailing lists by providing a simple link. Much like any email header (such as a From header, or the Subject header), it contains information – in this case a url. If you unsubscribe from an email using the automated feature in Yahoo/Gmail, the unsubscribe header is checked. The unsubscribe is then processed at the url from the header.

There are some rules:

  1. The URL must also allow a POST (List-Unsubscribe-Post: List-Unsubscribe=One-Click) to invoke an immediate unsubscribe that has no further human interaction to submit. For this reason, List-Unsubscribe headers are also known as one-click Unsubscribe headers. 
  2. The List-Unsubscribe header must contain a https url. For example:  
    <https://unsubscribe.mailplus.nl/deliverabilityservice/unsubscribe?uns-uid=31300632&a=31734861&s=1942&d=JGuSHT>

Usually, the sending system is both the one processing the unsubscribes and the one setting the header. Read more about the specs of list email headers here.

Is the header required?

Both Yahoo and Gmail do say they will be checking for the List-Unsubscribe header more. They do not list any direct consequences from their side, but they do mention that it's likely you will receive more complaints if you do not add the header.

Note that in this context, complaints means reporting unsolicited or unwanted emails as spam or abuse via a process that is called a feedback loop. List-Unsubscribe headers are only required for marketing emails, not transactional mails. Although Yahoo and Gmail do not mention any direct consequences, Spotler does recommend setting the List-Unsubscribe header for all of your marketing emails.

List unsubscribe headers in SendPro

SendPro is built for transactional emails. This means most of our clients send emails that are not required to add a List-Unsubscribe header. However, some clients do send marketing emails. In those emails, the header should be added.


This can be done by setting it in your source system. SendPro then honours that header and does not remove or edit it. The url in the List-Unsubscribe header should point towards the system that handles your sender lists – typically your CRM system or marketing tool.

You can also set a header using the Set Header Flowstep. 

Set_Header.png

Note that the unsubscribes should be processed by the source system, not SendPro. SendPro is not a marketing tool, and has no lists to unsubscribe from. Thats why you have to use a url in this step.

For example: <https://unsubscribe.mailplus.nl/deliverabilityservice/unsubscribe?uns-uid=31300632&a=31734861&s=1942&d=JGuSHT>

Don't forget the <> around the link!

Unsubscribe header.png

How can SendPro help?

You are ultimately responsible for adding the header and processing any unsubscribes. We will of course assist you in adding the header (usually via a Set Header Flowstep) if you cannot do so yourself.

If you cannot or will not set the header, any feedback loop complaints will be handled by SendPro's Recipient Filter. Please note that the Recipient Filter will block all outgoing email to that client, and should not be used as a list management tool. Contact your SendPro Account Manager or Support if you have any questions or uncertainties.