Set up DMARC and see who's sending email using your brand's domain.

Expanded support for using Broadcast Message Streams via SMTP

If you want to protect your deliverability, it’s important to separate your transactional and promotional email. With Postmark’s Message Streams, we help you make sure that the different types of email never ever mix: Transactional Message Streams are for your invoices, password reset emails, or similar and Broadcast Message Streams handle your newsletters, promotions, or other marketing email.

New to Broadcast sending with Postmark?

Promotional and transactional email should never mix, so we’ve created a parallel but completely separate infrastructure to handle all your promotional emails: Broadcast Message Streams.

Learn more

For us to process your mail fast and reliably, you have to let us know whether your email is a transactional or broadcast message. But when sending via SMTP, we learned that some of you were running into issues.

Specifying Message Streams when sending via SMTP #

When sending mail with Postmark via SMTP, there used to be only one option for you to specify a Message Stream: You’d authenticate with a Server Token and specify the Message Stream you’d like to use with the `X-PM-Message-Stream` header (that’s the Message Stream header). If you have the ability to set custom headers, this works great. But we’ve heard from some of you that your SMTP clients don’t let you set custom headers, making it impossible to define a Message Stream for sending. That’s not cool, so we set out on a mission to fix that!

New: Custom SMTP Tokens for your Message Streams #

In addition to the server-level Tokens you know already, you now have the ability to create SMTP Tokens for all of your Message Streams. These new Tokens will let you authenticate and send email via a Message Stream of your choice—without you having to touch the email header.

How to generate Message Stream SMTP Tokens in Postmark #

You can generate a dedicated SMTP Token for every outgoing Message Stream, whether that’s a broadcast or a transactional stream. Simply navigate to the Settings tab of the Message Stream you’d like to send through to generate the two keys you’ll need for SMTP sending:

  • The Access Key acts as the username for the SMTP connection.
  • The Secret Key acts as the password for the SMTP connection.

To learn more about the different types of Tokens in Postmark, check out our help documentation.

You find the shiny new SMTP Tokens in your Message Stream settings in Postmark

💡 Good to know: #

Specifying your Message Streams via a custom header still works, so if that’s how you configure your SMTP sending, you don’t have to make any changes. Message Stream Tokens are simply an additional way to specify a Message Stream for all senders who can’t add custom headers. It’s also a great option for those of you who’d like to add an extra layer of security. When creating a Message Stream Token, your Secret Key is different from your Access Key—and it won’t be visible to anyone after you created it 🔒—making it an even more secure authentication method than our good old Server Tokens.

Do you have any questions or feedback? Let us hear it! #

We hope that our brand-new Tokens make it easier for you to send mail via Message Streams, no matter what SMTP client you use for sending. Definitely let us know what you think about this update. And if you have any questions, please reach out. We’re here to help!

Bettina Specht

Bettina Specht

Product Lead at Postmark. Likes squirrels. 🐿