Official Postmark MCP Server     

Send emails with Postmark using Claude and other MCP-compatible AI assistants.

Features

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

Useful Docs

• 📒 API Documentation
• 🔎 API Explorer
• 📖 Engineering Articles

Feedback

We'd love to hear from you! Please share your feedback and suggestions using our feedback form.

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Setup

Requirements

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

Installation (Local Development)

Clone the repository:

git clone https://github.com/ActiveCampaign/postmark-mcp
cd postmark-mcp

Install dependencies:

npm install
# or
yarn
# or
bun install

Configuration (Local Development)

Create your own environment file from the example

cp .env.example .env

Edit your .env to contain your Postmark credentials and settings.

Important: This is intended for local development purposes only. Secrets should never be stored in version control and .env type files should be added to .gitignore.

Run the server:

npm start
# or
yarn start
# or
bun start

Cursor Quick Install

After installing the MCP, update your configuration to set:

• POSTMARK_SERVER_TOKEN
• DEFAULT_SENDER_EMAIL
• DEFAULT_MESSAGE_STREAM (default: outbound)

Claude and Cursor MCP Configuration Example

{
  "mcpServers": {
    "postmark": {
      "command": "node",
      "args": ["path/to/postmark-mcp/index.js"],
      "env": {
        "POSTMARK_SERVER_TOKEN": "your-postmark-server-token",
        "DEFAULT_SENDER_EMAIL": "[email protected]",
        "DEFAULT_MESSAGE_STREAM": "your-message-stream"
      }
    }
  }
}

Tools

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

Table of Contents

• Email Management Tools
  • sendEmail
  • sendEmailWithTemplate
• Template Management Tools
  • listTemplates
• Statistics & Tracking Tools
  • getDeliveryStats

Email Management Tools

1. sendEmail

Sends a single text email.

Example Prompt:

Send an email using Postmark to [email protected] 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": "[email protected]",
  "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": "[email protected]", // Optional, uses DEFAULT_SENDER_EMAIL if not provided
  "tag": "meetings" // Optional
}

Response Format:

Email sent successfully!
MessageID: message-id-here
To: [email protected]
Subject: Meeting Reminder

2. sendEmailWithTemplate

Sends an email using a pre-defined template.

Example Prompt:

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

Expected Payload:

{
  "to": "[email protected]",
  "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": "[email protected]", // Optional, uses DEFAULT_SENDER_EMAIL if not provided
  "tag": "onboarding" // Optional
}

Response Format:

Template email sent successfully!
MessageID: message-id-here
To: [email protected]
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

API Request Headers

All requests to the Postmark API that are made directly by this server include the following headers for client identification and correlation:

These headers are sent on every request to the Postmark API. This server uses its own HTTP client (no postmark npm package) so that MCP traffic is identified as postmark-mcp and not as the Node.js SDK.

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.

License

MIT © ActiveCampaign