postmarkapp.com

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About Postmark

Postmark is a transactional email service operated by ActiveCampaign, focused exclusively on reliable delivery of application-triggered emails such as password resets, receipts, and notifications. It uses separate Message Streams to segregate transactional and broadcast email infrastructures, protecting sender reputation. In early 2026 Postmark restructured its pricing from pure volume tiers to plan-based tiers (Basic, Pro, Platform) while maintaining volume-based overage charges. It does not offer marketing automation.

AI Agent Use Cases

- Message Streams for isolated transactional and broadcast sending infrastructure

- 45-day full content history with configurable retention up to 365 days

- Inbound email processing (Pro and Platform plans)

- Webhooks for delivery, bounce, and open/click events

- Pre-built templates for common transactional emails

- Dedicated IPs available as $50/month add-on for high-volume senders

Available Actions

These are the specific actions that AI agents can perform with this tool

Batch Send Emails

6 inputs

Send multiple emails in a single HTTP request using Postmark's batch email endpoint.

Inputs

From

The email address of the sender.

The email address of the receiver.

Subject

The subject of the email.

TextBody

The plain text content of the email.

HtmlBody

The HTML content of the email.

MessageStream

The identifier of the message stream, typically 'outbound'.

Edit Server Details

16 inputs

Update server configuration details such as name, color, webhook URLs, and tracking options.

Inputs

Name

Name of the server.

Color

Color of the server in the rack screen.

RawEmailEnabled

Include raw email content in inbound webhook payloads.

DeliveryHookUrl

URL to POST to every time email is delivered.

SmtpApiActivated

Specifies whether SMTP is enabled on this server.

InboundHookUrl

URL to POST to every time an inbound event occurs.

BounceHookUrl

URL to POST to every time a bounce event occurs.

OpenHookUrl

URL to POST to every time an open event occurs.

PostFirstOpenOnly

If true, only the first open by a particular recipient initiates the open webhook.

TrackOpens

Indicates if all emails have open tracking enabled.

TrackLinks

Indicates link tracking enabled status for email links. Options are 'None', 'HtmlAndText', 'HtmlOnly', 'TextOnly'.

ClickHookUrl

URL to POST to when a unique click event occurs.

InboundDomain

Inbound domain for MX setup.

InboundSpamThreshold

Maximum spam score for an inbound message before it's blocked.

IncludeBounceContentInHook

Include bounce content in webhook.

EnableSmtpApiErrorHooks

Include SMTP API Errors with bounce webhooks.

Get Server Details

1 input

Retrieve the details of a specific server using the API

Inputs

X-Postmark-Server-Token

This token is used for authenticating the request and authorizing access to server details.

List Servers

Retrieve a list of all servers configured on the Postmark account.

Send Email

10 inputs

Send a single email using Postmark's API.

Inputs

From

The email address of the sender. Can include a name, e.g., 'John Doe <email@example.com>'.

The email address(es) of the recipient(s). Can include names and multiple addresses separated by commas.

The email address(es) to send a carbon copy. Can include names and multiple addresses.

Bcc

The email address(es) to send a blind carbon copy. Can include names and multiple addresses.

Subject

The subject of the email. Must be less than 2000 characters.

Tag

A categorization label for the email.

HtmlBody

HTML formatted message body.

TextBody

Plain text message body.

ReplyTo

The email address for reply-to responses.

MessageStream

Optional message stream to use for this email (e.g., 'outbound').