Custom headers in webhooks?

Hello ! The documentation on transactional webhooks mentions that custom headers added on the emails are sent back to the webhook.

However I am observing that headers are not in the payload that comes back in the webhook ?

More info on my set-up : I am sending emails in a Rails app through SMTP, and adding the headers in the ActionMailer action directly. I can see the X-Mailin-YYYY header in the email, but not in the webhook?

My headers are:
X-Mailin-Env
X-Mailin-Vote-Id
X-Mailing-Email-Type

Hi @captaincause , thanks for posting on this community.

From the email the X-Mailin-Custom header is passed on to the webhooks payload, but
any other custom header is not forwarded to client in the webhook payload.

So you can add the info in this X-Mailin-Custom header, and receive the same field in the webhook payload.