Docs
/
Contact supportLog inGet started
Overview
Overview
Layouts
Settings and overrides
Sending attachments
Client previews
Amazon SES
Knock (test)
MailerSend
Mailgun
Mailjet
Mailtrap
Mandrill
Postmark
Resend
SendGrid
SMTP
SparkPost
Get startedLog inContact support
Platform
Integrations
In-app UI
API reference
CLI reference
Management API
Developer tools
Tutorials
Integrations
Email
Postmark

How to send email with Postmark

How to send transactional email notifications to Postmark with Knock.

Knock integrates with Postmark to send email notifications to your users. This page describes how to get started with Postmark in Knock, including necessary provider configurations and additional data you can pass through to Postmark.

Features

#
  • Attachments support
  • Delivery tracking
  • Bounce Support
  • Knock link and open tracking
  • Postmark link and open tracking
  • Per environment configuration
  • Sandbox mode

Getting started

#

You can create a new Postmark channel in the dashboard under the Channels and sources page in your account settings. From there, you'll need to configure the channel for each environment you have.

Channel configuration

#

The following channel settings should be configured per environment. Navigate to Channels and sources in your dashboard account settings, select your Postmark channel, then click "Manage configuration" under the environment that you'd like to configure.

Fields marked with an * are required.

Knock settings

Sandbox modeboolean

Whether to enable sandbox mode for your Postmark channel.

Knock open trackingboolean

Whether to enable Knock email-open tracking.

Knock link trackingboolean

Whether to enable Knock link-click tracking.

Provider settings for Postmark

API keystring*

The API key for your Postmark server.

Open trackingboolean

Whether to enable Postmark email-open tracking.

Link trackingboolean

Whether to enable Postmark link-click tracking.

From email addressstring | liquid*

The default sender email address (can use Liquid tags).

From namestring | liquid

The default sender name (can use Liquid tags).

When configured, these optional overrides will apply to all emails sent from this channel in the configured environment. Learn more about email channel overrides here.

Tostring | liquid

The To email address that email notifications will be sent to (can use Liquid tags). This value will override the designated recipient's email address.

Ccstring | liquid

The CC email address that email notifications will be sent to (can use Liquid tags).

Bccstring | liquid

The BCC email address that email notifications will be sent to (can use Liquid tags).

Reply-tostring | liquid

The reply-to email address that will be included on email notifications (can use Liquid tags).

Payload overridesJSON (string) | liquid

Provide a JSON object to merge into the API payload that is sent to the downstream provider.

Set optional per-environment conditions for this channel. These conditions are evaluated each time a workflow run encounters a step that uses this channel in the configured environment. If the conditions are not met, the step will be skipped.

Additional data sent

#

Knock sends the following attributes along with your emails:

  • Metadata.sender: always set to knock.app
  • Metadata.knock_message_id: the ID of the message this email is associated with
  • Metadata.knock_recipient_id: the Knock ID of the recipient this email is being sent to
  • Tag: the key of the workflow this message was generated from

You can learn about the role of these Postmark attributes in the Postmark API documentation.

Recipient data requirements

#

In order to send an email notification you'll need a valid email property set on your recipient.

Delivery status webhooks

#

When enabled, Postmark will send delivery status updates directly to Knock via webhooks, allowing you to track the full lifecycle of your email messages in real-time.

Prerequisites

#

Before enabling delivery status webhooks, you need:

  1. A verified sender signature or domain in Postmark
  2. A Postmark channel configured in Knock (see the getting started section above)
  3. Access to your Postmark server webhook settings

Setting up delivery status webhooks

#
1

Enable delivery status webhooks in Knock

  1. Navigate to Channels and sources in your Knock dashboard
  2. Select your Postmark channel
  3. Click "Manage configuration" for the environment you want to configure
  4. Scroll to the "Incoming message status updates" section and enable incoming webhooks
  5. Copy the generated webhook URL - you'll need this in the next step
2

Configure webhooks in Postmark

In the Postmark dashboard, configure webhooks to send delivery events to Knock:

  1. Go to your Postmark server and select the server you're using with Knock
  2. Navigate to the Webhooks tab
  3. Add the webhook URL from Knock to both webhook configurations:
    • Delivery webhook - Add the Knock webhook URL and click "Save delivery webhook"
    • Bounce webhook - Add the Knock webhook URL and click "Save bounce webhook"
  4. Postmark will automatically begin sending events to Knock

Supported delivery statuses

#

When delivery status webhooks are enabled for Postmark, Knock will update message statuses based on these Postmark webhook events:

Postmark Event TypeKnock StatusDescription
DeliverydeliveredThe email was successfully delivered to the recipient's mail server
BouncebouncedThe email bounced due to invalid recipient or domain

Troubleshooting

#

If delivery status updates aren't appearing in Knock:

  1. Check webhook configuration. Verify both the Delivery and Bounce webhooks are configured with the correct Knock webhook URL in your Postmark server settings.
  2. Verify sender signature. Ensure you're sending from a verified sender signature or domain in Postmark.
  3. Check Postmark activity. Review the Activity page in Postmark to ensure emails are being sent successfully.

Using overrides to customize notifications

#

We provide full support for overriding the payload of your email notifications. This enables you to customize the API request that Knock sends to Postmark on your behalf.

Targeting a specific MessageStream

#

Knock does not target a specific MessageStream when sending your transactional email notifications to Postmark. This means that Postmark defaults your notifications to the "outbound" transactional stream.

For marketing use cases such as newsletters or product updates sent to large recipient lists, and particularly when leveraging Knock's broadcasts feature, we recommend following Postmark's best practices for sending promotional messaging via a separate MessageStream.

1

Configure a broadcast MessageStream in Postmark

Configure a Broadcast-type message stream in your Postmark account. Read more about the MessageStream API here.

2

Set a payload override in Knock

Set a payload override in Knock with the ID of the MessageStream that you'd like to target. This can be done at either the channel configuration level or directly in the settings of your workflow's email channel step: