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Sendy + Postmark Broadcast Streams (SMTP)

edited May 2021 in Troubleshooting


Postmark have recently opened up the ability to use their services for 'broadcast' messages.

I can see that in Sendy I can setup SMTP as a method for sending msgs.

Here is what postmark say about setting up SMTP for them:


To send with Broadcast Message Streams via SMTP, it requires the ability to add additional Headers with your SMTP client. The X-PM-Message-Stream header is your Broadcast Message Stream ID.

Ports: 25, 2525, or 587
Username: server token
Password: server token
Authentication: Plain text, CRAM-MD5, or TLS
Header: X-PM-Message-Stream: broadcasts

As you can see it requires the ability to add additional Headers with the SMTP client (sendy).

How can I configure this in Sendy to do this?

Thank you.


  • Would love to see support for this in Sendy. With a feature to add custom headers it could be useful for other purposes too.

  • Dying for this to be supported, as well.

  • Did I see the latest 6.0 update today now allows sending from any SMTP service? Does that mean Postmark is finally supported?

  • I use postmark as well, so I upgraded to v6, and tested it successfully today. We can't yet set custom headers it appears, so Sendy just sends from postmark's "default transactional stream".

  • I meant to say this but forgot: it works, but, it's not integrated. That is, you need to go to postmark to see details about the send, because sendy is not capturing the results of each send via postmark's smtp mechanism. FYI

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