Why should I use the List-Unsubscribe header?

It gives inbox providers a safe and standard way to handle unsubscribes, which reduces spam complaints and protects your domain reputation.

Is a mailto link enough for List-Unsubscribe?

A mailto link is better than nothing, but a one click HTTPS link plus mailto fallback gives the best user experience.

Do I still need an unsubscribe link in the body?

Yes. The header complements, not replaces, a visible unsubscribe link in the body of your email.

How to set up List-Unsubscribe on Postmark

Step by step List-Unsubscribe setup for Postmark: complete instructions, examples, verification commands, and common pitfalls.

Want to check your domain while following this guide?

Run a free SPF, DKIM and DMARC check on your domain to see exactly what is passing and what needs fixing.

No signup required. Works on any domain.

search Run a Free Domain Check notifications_active Monitor my domain

This is a reference guide for configuring List-Unsubscribe on Postmark. Use it while editing DNS or when troubleshooting deliverability.

Tip: Configure List-Unsubscribe for Postmark in minutes. This guide keeps it practical and safe. Then verify everything with the InboxGreen Free Checker.

Provider-specific notes for Postmark

Postmark uses Sender Signatures, not domain-level DKIM by default. Each sender signature domain gets its own DKIM record published by Postmark.
Postmark DKIM keys rotate periodically. If DKIM suddenly fails, check the Postmark dashboard for an updated record value.
Postmark → Sender Signatures → Domain → DKIM.

What is List-Unsubscribe?

List-Unsubscribe is a message header that gives inboxes a safe, machine readable way to unsubscribe. Gmail and Outlook often show a clear unsubscribe link when it is present and valid, which reduces spam complaints and protects your sender reputation.

How to enable it in practice

In your sending platform, enable the List-Unsubscribe header or macro in templates.
Use a one click HTTPS link as the main method, with a mailto address as fallback.
Test by sending to a Gmail address and checking “Show original”.

Example headers

List-Unsubscribe: <https://yourdomain.com/u/abcd1234>, <mailto:[email protected]?subject=unsubscribe>
List-Unsubscribe-Post: List-Unsubscribe=One-Click

Common mistakes

Using a broken or redirected unsubscribe link that fails when clicked.
Only providing a mailto address without a one click URL.
Failing to apply the unsubscribe globally across lists and tools.

Free Deliverability Scan

Check SPF, DKIM, DMARC and List-Unsubscribe for your domain in seconds.

Useful tools

tune SPF Generator tune DMARC Generator verified Badges