Setting up the List-Help header

  • Updated

This topic describes how to switch from the List-Unsubscribe header to the List-Help header for transactional mails.

List-Unsubscribe header

Currently, every email you send via Optimizely Campaign contains a List-Unsubscribe header. This is an unsubscribe link that can be executed via the email header. Some ISPs such as Gmail or Microsoft additionally display an unsubscribe button based on this header in the inbox overview, from which the recipients can simply unsubscribe with one click without having to open the mailing. The normal unsubscribe link in the mailing footer is a separate feature and is not related to the List-Unsubscribe header.

Example List-Unsubscribe header

List-Unsubscribe: <>,< List-Unsubscribe=One-Click>

List-Help header for transactional mails

However, the List-Unsubscribe header does not make sense in every mailing, e.g., in non-list-based emails such as activation emails, order confirmations or password reset emails. The List-Help header may be used instead for ad-free, transactional mails. It is also part of the email header, but instead of an unsubscribe link it contains a URL to a website that explains to the recipients why they have received this mailing, how they can unsubscribe or why unsubscribing from it is neither possible nor necessary.

An unsubscribe button is not displayed. There is also the option of adding a contact email address in the List-Help header area, which is optional. The use of the List-Help header is compliant with CSA guidelines and industry best practices.

Example List-Help header

List-Help: <>,<mailto:>


To switch from List-Unsubscribe header to List-Help header, note the following requirements for the mailing in which this is to be used, as well as for the List-Help URL itself:

Mailing requirements

  • The implementation is only possible for mailings of type "transactional mail" or "confirmation mail".
  • In terms of content, the mailings must contain transactional content triggered by the recipient, e.g., activation emails, order confirmations, invoices or password reset emails.
  • The mailing must not contain any advertising content. This includes product advertising, newsletter advertising, advertising for the online shop, vouchers and all measures aimed at a (further) purchase. Company branding can be used.

List-Help URL/website requirements

  • The List-Help URL must lead to an active website via HTTPS, HTTP is not sufficient.
  • The website must contain the information as to why the recipient received the mailing.
  • The website must contain information on how to unsubscribe from further emails or why unsubscribing is neither possible nor necessary.


To switch from the List-Unsubscribe header to the List-Help header, contact customer support.

Provide customer support with the following information:

  • Reason for request
  • Name / ID of the Optimizely Campaign client
  • Name / ID of the mailing
  • List-Help URL