Return path

The return-path header (also often referred to simply as return-path) is nothing more than the email address from which the email is sent and where the bounce notifications are managed. This can be easily seen if you check the headers of any email you have received.

To give you a context of Return-Path, here you can see an example of an email header:

From: Remitente de ejemplo ([[email protected]](mailto:[email protected]))

Subject: Este email lo tienes que leer, es navidad

Date: December 25, 2021 9:30:55 PM PDT

To: [[email protected]](mailto:[email protected])

Return-Path: <[[email protected]](mailto:[email protected])>

Envelope-To: [[email protected]](mailto:[email protected])

Delivery-Date: Fri, 14 Dec 2021 5:30:01 -0700

Received: from [smtp.micorreo.com](http://smtp.micorreo.com) ([[xxx.xxx.xxx.xxx](http://xxx.xxx.xxx.xxx)]:54907) by [servidor.otrocorreo.com](http://servidor.otrocorreo.com) with esmtp (Exim 4.63) (envelope-from <[[email protected]](mailto:[email protected])>)…

In addition to return-path, it is also called reverse path, sender, sender from, 5321-DE, De_ and Errors, among others. And it is the address marked as return-path that receives the information of all the bounces generated when we send an email.

You already know it, if you send mass mailing campaigns you already worked with return-path, as you received many bounce notifications.

1. What is return path for?

In a few words, it is used to process the bounces, so it is the email address to where the recipient’s email server should send the notifications about the management of the bounced emails (regardless of the reason that generated the bounce).

The return-path value is added by the email provider each time an email is sent, and must always be present in the headers of any email that is sent.

If this is not the case, it will not be possible to correctly notify the existence of a bounce and we may be sending to an email that doesn’t work constantly. This, in principle, may not have much importance but it is vital, since it can generate a problem for the reputation of the sender domain of the email.