substack-publisher-mcp

MCP server for Substack's official Publisher API

Note: This is an unofficial, community-developed tool and is not affiliated with, endorsed by, or supported by Substack, Inc.

The first MCP server for Substack's official Publisher API. Query post analytics, subscriber counts, and publication data directly from Claude, Cursor, or any MCP client.

Why this server?

Prerequisites

• Node.js 18+
• Substack Publisher API key — Available from the Publisher API docs

Quick Start

1. Install

git clone https://github.com/dkships/substack-publisher-mcp.git
cd substack-publisher-mcp
npm install && npm run build

2. Configure your MCP client

Add to your client's MCP config file:

{
  "mcpServers": {
    "substack": {
      "command": "node",
      "args": ["/path/to/substack-publisher-mcp/dist/index.js"],
      "env": {
        "SUBSTACK_API_KEY": "your-api-key-here"
      }
    }
  }
}

Claude Code users: Add "type": "stdio" to the server config.

3. Start using it

Ask Claude: "Show me my recent posts" or "What are my subscriber counts for the last 30 days?"

Tools

All tools accept an optional publication parameter when multiple publications are configured.

Example responses

[
  {
    "date": "2025-01-15",
    "total_email_subscribers": 25000,
    "paid_subscribers": 500,
    "free_trial_subscribers": 10,
    "comp_subscribers": 50,
    "gift_subscribers": 15,
    "lifetime_subscribers": 0,
    "founding_subscribers": 25
  }
]

{
  "clicks": 320,
  "opens": 5400,
  "post_id": 12345678,
  "recipients": 10000,
  "views": 6100,
  "new_free_subscriptions": 80,
  "new_paid_subscriptions": 5,
  "estimated_revenue_increase": 400
}

{
  "posts": [
    {
      "title": "My Latest Post",
      "audience": "only_paid",
      "subtitle": "A deep dive into the topic",
      "postDate": "2025-01-15T12:00:00.000Z",
      "urlSlug": "my-latest-post",
      "coverImage": "https://substackcdn.com/image/..."
    }
  ],
  "next": "abc123cursor"
}

Multiple publications

If you manage multiple Substack publications, configure a separate API key for each using the SUBSTACK_API_KEY_<NAME> pattern:

{
  "mcpServers": {
    "substack": {
      "command": "node",
      "args": ["/path/to/substack-publisher-mcp/dist/index.js"],
      "env": {
        "SUBSTACK_API_KEY_MAIN": "your-main-blog-key",
        "SUBSTACK_API_KEY_TECH": "your-tech-newsletter-key",
        "SUBSTACK_API_KEY_COMPANY": "your-company-updates-key"
      }
    }
  }
}

Then specify which publication to query:

"Show me subscriber counts for main" "List recent posts from the tech publication"

Use list_publications to see all configured publication names.

Troubleshooting

API Reference

This server wraps the Substack Publisher API. See Substack's documentation for details on available data and rate limits.

Contributing

See CONTRIBUTING.md for guidelines.

License

MIT License. See LICENSE for details.

Substack is a trademark of Substack, Inc. This project is not affiliated with Substack, Inc. Use of the Substack name is for descriptive purposes only.