Email MCP Server

A minimal, production-ready MCP (Model Context Protocol) server that enables Claude Desktop to send emails via Mailjet's API over Server-Sent Events (SSE).

Quick Start

1. Deploy the Server

Local Development:

# Clone and setup
git clone <your-repo>
cd email-mcp-server
pip install -r requirements.txt

# Configure environment
cp .env.example .env
# Edit .env with your API tokens

# Run server
python main.py
# Server runs on http://localhost:8000

Production Deploy (Railway/Render/Vercel):

1. Fork this repository
2. Connect to your hosting platform
3. Set environment variables:
   • VALID_API_TOKENS=your-secure-tokens-here
   • HOST=0.0.0.0
   • PORT=8000

2. Get Your API Token

Visit your deployed server at https://your-domain.com and get a valid API token from the VALID_API_TOKENS environment variable.

3. Configure Claude Desktop

Add this to your Claude Desktop MCP configuration file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "email-sender": {
      "transport": {
        "type": "sse",
        "url": "https://your-domain.com/sse?api_token=your-api-token"
      }
    }
  }
}

4. Get Mailjet Credentials

1. Sign up at Mailjet.com (free tier available)
2. Go to Account Settings API Keys
3. Copy your API Key and Secret Key

5. Send Emails with Claude

Now you can ask Claude to send emails:

"Send an email to john@example.com with the subject 'Meeting Follow-up' saying 'Thanks for the great discussion today. Let's schedule a follow-up for next week.'"

Claude will ask for your Mailjet credentials the first time.

Security Features

• API Token Authentication: Each request requires a valid token
• User-Provided Credentials: Server never stores user email credentials
• Input Validation: Email format validation and error handling
• CORS Protection: Configurable origin restrictions

API Endpoints

• GET / - Server status and information
• GET /sse?api_token=TOKEN - SSE endpoint for MCP protocol
• POST /mcp?api_token=TOKEN - Direct MCP message handling (debugging)

Environment Variables

HOST=0.0.0.0                    # Server host
PORT=8000                       # Server port
VALID_API_TOKENS=token1,token2  # Comma-separated valid tokens

Usage Examples

Basic Email:

Send email to user@domain.com saying "Hello World"

With HTML:

Send a professional email to client@company.com with subject "Proposal" including both plain text and HTML formatting

Multiple Recipients (coming soon):
Currently supports single emails only. Bulk email functionality planned for v2.

Troubleshooting

Common Issues:

1. "Invalid API token" - Check your token in the SSE URL
2. "Invalid Mailjet credentials" - Verify your API key and secret
3. "Invalid email format" - Ensure email addresses are properly formatted
4. Connection timeouts - Check your server deployment status

Architecture

• FastAPI - Modern Python web framework
• SSE Transport - Real-time MCP protocol communication
• Mailjet API - Reliable email delivery service
• In-Memory Auth - Simple token validation (no database required)

License

MIT License - feel free to use in your own projects!

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Submit a pull request

For major changes, please open an issue first to discuss the proposed changes.