Adding a custom Return-Path domain

What is the Return-Path?

The Return-Path is the address where bounces and other email feedback are sent. It is specified by the Return-Path header in an email. The default Return-Path for emails sent through Postmark is:

Return-Path: <>

It is also described as:

  • bounce address
  • reverse path
  • envelope from

Why set a custom Return-Path?

A custom Return-Path isn't really needed and shouldn't affect deliverability. If you have a DMARC policy for your domain, you should set up a custom Return-Path to achieve alignment.

If you send emails from, then you can still pass SPF and DKIM authentication but the Return-Path and From address are not aligned. When you set up a Return-Path domain of and send emails from then the domains will be aligned. When you send emails with a custom Return-Path, the header would look like:

Return-Path: <>

What is needed to set a custom Return-Path?

For your Return-Path domain, you need to create a CNAME record in DNS that points to This is so that Postmark is still able to collect bounces and other feedback sent to that address.

How to set a custom Return-Path?

While logged into Postmark, select the "Sender Signatures" tab and select the "Authentication" link on the domain you want to add the custom Return-Path domain on and navigate to the heading "Set up a custom Return-Path".

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