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HIPAA Notice: If you plan to send or reference PHI when using the Paubox MCP connector through Claude, you must have a Business Associate Agreement (BAA) in place with Anthropic. BAAs are available on Claude Team and Enterprise plans. Your Paubox subscription covers email delivery, it does not cover protected health information (PHI) processed within Claude’s context window.
1

Get your API key

Before connecting, you need a Paubox Email API key and API username. See Authentication for how to generate them from the Paubox dashboard.
2

Connect via Claude.ai

  1. In Claude.ai, open Settings > Integrations.
  2. Click Add connector and enter the server URL:
https://mcp.paubox.com
  1. A Configure Paubox form opens automatically. Enter your API username and API key.
  2. Click Save. Claude stores your credentials as a secure token and sends it on every request.
Claude will discover the available Paubox tools automatically.
3

Connect via Claude Desktop

Open (or create) claude_desktop_config.json and add the paubox entry to mcpServers:
{
  "mcpServers": {
    "paubox": {
      "url": "https://mcp.paubox.com"
    }
  }
}
The config file is located at:
  • macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
  • Windows: %APPDATA%\Claude\claude_desktop_config.json
When using the HTTP config, Claude Desktop will open a browser window to the Configure Paubox form to collect your credentials. Restart Claude Desktop after saving.
4

Connect via Claude Code

Run this command once with your API credentials (no credential prompts afterward):
claude mcp add paubox \
  -e PAUBOX_API_KEY=your_api_key \
  -e PAUBOX_API_USER=your_api_username \
  -- npx @paubox/mcp@latest
Claude Code spawns the package locally and injects the credentials as environment variables.
5

Test the connection

Ask Claude to verify your credentials:
“Use the Paubox MCP server to validate my credentials.”
Claude will call validate_credentials and confirm your API key is working. Then try sending a test email:
“Send a test email to me@example.com from sender@yourdomain.com with the subject ‘Hello from MCP’.”
Claude will call send_secure_email and return a sourceTrackingId you can use to check delivery status.

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Other MCP-compatible clients

Any client that supports the MCP specification can connect using either transport:
  • HTTP: https://mcp.paubox.com; use OAuth (credential form in the client UI) or set x-paubox-api-key and x-paubox-api-user as custom request headers
  • stdio: run npx @paubox/mcp@latest with PAUBOX_API_KEY and PAUBOX_API_USER set in the environment