Add "In-Reply-To" header on "Send Email" (SMTP) node

The idea is:

Add the headers “In-Reply-To” and “References” to Send Email (SMTP) node, to allow sending emails as replais to recieved emails.

My use case:

I want to reply an incoming email from n8n itself with an automated message. Now I just add "Re: " at the beggining of the subject, and mdoern email clients like Gmail treat this as a reply. But it is not the best way to do it, as it is very superficial. A better way to do it is to add the email ID (which is delivered to me on the Recieve email via IMAP node) at the “In-Reply-Tio” and “References” headers on SMTP, but this is not possible on the SMTP node on n8n.

Any resources to support this?

https://www.jwz.org/doc/threading.html

I’m also struggling with this. Did you find a solution @ruccc ?

Very interested in this. With the AI capabilities this is a must nowadays.

The Send Email node already has an option for reply-to, but not yet for references:

1 Like

Still no solution to set the In-Reply-To header so that a clean e-mail thread can be kept during conversations? :frowning:

There is already a PR for this (open since one year): feat: add in-reply-to and references to reply emails by jmrobles · Pull Request #9346 · n8n-io/n8n · GitHub

I have made a custom node that allows you to add custom headers to SMTP emails.

The README includes instructions on replying to email threads.