Postmark MCP Server

An MCP server implementation for Postmark email services.

Features

Exposes a Model Context Protocol (MCP) server for sending emails via Postmark
Simple configuration via environment variables
Comprehensive error handling and graceful shutdown
Secure logging practices (no sensitive data exposure)
Automatic email tracking configuration

Requirements

Node.js (v16 or higher recommended)
A Postmark account and server token

Setup

Clone the repository:
git clone https://github.com/ActiveCampaign/postmark-mcp cd postmark-mcp
Install dependencies:
npm install
Configure environment variables:
- Copy .env.example to .env:
  cp .env.example .env
- Edit .env and fill in your Postmark credentials and settings.
Variable Description Required
POSTMARK_SERVER_TOKEN Your Postmark server API token Yes
DEFAULT_SENDER_EMAIL Default sender email address Yes
DEFAULT_MESSAGE_STREAM Postmark message stream (e.g., 'outbound') Yes
Run the server:
npm start

Variable	Description	Required
POSTMARK_SERVER_TOKEN	Your Postmark server API token	Yes
DEFAULT_SENDER_EMAIL	Default sender email address	Yes
DEFAULT_MESSAGE_STREAM	Postmark message stream (e.g., 'outbound')	Yes

Quick Install via Cursor Deeplink

You can quickly install this MCP server in Cursor by clicking the following button:

Note: After clicking the button, you'll need to:
Set your POSTMARK_SERVER_TOKEN in the MCP configuration
Set your DEFAULT_SENDER_EMAIL in the MCP configuration
Set your DEFAULT_MESSAGE_STREAM in the MCP configuration (defaults to "outbound")

Claude and Cursor MCP Configuration Example

{
  "mcpServers": {
    "Postmark": {
      "command": "your-node-path", // which node
      "args": ["/Users/your-name/your-location/postmark-mcp/index.js"], // realpath index.js
      "env": {
        "POSTMARK_SERVER_TOKEN": "your-postmark-server-token",
        "DEFAULT_SENDER_EMAIL": "your-default-sender-email",
        "DEFAULT_MESSAGE_STREAM": "your-default-message-stream"
      }
    }
  }
}

Tool Reference

This section provides a complete reference for the Postmark MCP server tools, including example prompts and expected payloads for each.

Email Management Tools

1. sendEmail

Sends a single text email.

Example Prompt:

Send an email using Postmark to recipient@example.com with the subject "Meeting Reminder" and the message "Don't forget our team meeting tomorrow at 2 PM. Please bring your quarterly statistics report (and maybe some snacks).""

Expected Payload:

{
  "to": "recipient@example.com",
  "subject": "Meeting Reminder",
  "textBody": "Don't forget our team meeting tomorrow at 2 PM. Please bring your quarterly statistics report (and maybe some snacks).",
  "htmlBody": "HTML version of the email body", // Optional
  "from": "sender@example.com", // Optional, uses DEFAULT_SENDER_EMAIL if not provided
  "tag": "meetings" // Optional
}

Response Format:

Email sent successfully!
MessageID: message-id-here
To: recipient@example.com
Subject: Meeting Reminder

2. sendEmailWithTemplate

Sends an email using a pre-defined template.

Example Prompt:

Send an email with Postmark template alias "welcome" to customer@example.com with the following template variables:
{
  "name": "John Doe",
  "product_name": "MyApp",
  "login_url": "https://myapp.com/login"
}

Expected Payload:

{
  "to": "customer@example.com",
  "templateId": 12345, // Either templateId or templateAlias must be provided, but not both
  "templateAlias": "welcome", // Either templateId or templateAlias must be provided, but not both
  "templateModel": {
    "name": "John Doe",
    "product_name": "MyApp",
    "login_url": "https://myapp.com/login"
  },
  "from": "sender@example.com", // Optional, uses DEFAULT_SENDER_EMAIL if not provided
  "tag": "onboarding" // Optional
}

Response Format:

Template email sent successfully!
MessageID: message-id-here
To: recipient@example.com
Template: template-id-or-alias-here

Template Management Tools

3. listTemplates

Lists all available templates.

Example Prompt:

Show me a list of all the email templates available in our Postmark account.

Response Format:

📋 Found 2 templates:

• Basic
  - ID: 12345678
  - Alias: basic
  - Subject: none

• Welcome
  - ID: 02345679
  - Alias: welcome
  - Subject: none

Statistics & Tracking Tools

4. getDeliveryStats

Retrieves email delivery statistics.

Example Prompt:

Show me our Postmark email delivery statistics from 2025-05-01 to 2025-05-15 for the "marketing" tag.

Expected Payload:

{
  "tag": "marketing", // Optional
  "fromDate": "2025-05-01", // Optional, YYYY-MM-DD format
  "toDate": "2025-05-15" // Optional, YYYY-MM-DD format
}

Response Format:

Email Statistics Summary

Sent: 100 emails
Open Rate: 45.5% (45/99 tracked emails)
Click Rate: 15.2% (15/99 tracked links)

Period: 2025-05-01 to 2025-05-15
Tag: marketing

Implementation Details

Automatic Configuration

All emails are automatically configured with:

TrackOpens: true
TrackLinks: "HtmlAndText"
Message stream from DEFAULT_MESSAGE_STREAM environment variable

Error Handling

The server implements comprehensive error handling:

Validation of all required environment variables
Graceful shutdown on SIGTERM and SIGINT
Proper error handling for API calls
No exposure of sensitive information in logs
Consistent error message formatting

Logging

Uses appropriate log levels (info for normal operations, error for errors)
Excludes sensitive information from logs
Provides clear operation status and results

For more information about the Postmark API, visit Postmark's Developer Documentation.

This server cannot be installed

security - not tested

license - permissive license

quality - not tested

How are these scores calculated?

An MCP server implementation that enables sending emails via Postmark email services with features for sending plain text/HTML emails, using templates, tracking delivery statistics, and listing available templates.

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