joswr1ght/sslmate-mcp

SSLMate MCP Server

2025-07-02 | Joshua Wright | Written with GitHub Copilot and Claude Sonnet 4

A Model Context Protocol (MCP) server that provides SSL/TLS certificate search functionality using the CertSpotter API. Search Certificate Transparency logs to discover certificates for any domain, including comprehensive subdomain discovery.

What This Tool Does

This MCP server integrates with Claude Desktop to provide powerful certificate discovery capabilities:

• Certificate Search: Find SSL/TLS certificates in Certificate Transparency logs by domain name
• Subdomain Discovery: Search for certificates issued to all subdomains of a given domain (e.g., find all *.example.com certificates)
• Detailed Information: Get comprehensive certificate details including DNS names, issuers, validity periods, and more
• Expired Certificate Filtering: Option to include or exclude expired certificates from results
• Real-time Data: Access live Certificate Transparency log data through the CertSpotter API

Requirements

• Python 3.8 or later+
• uv package manager (install uv)
• SSLMate API Key (optional - free tier available at SSLMate)
• MCP CLient (tested with Claude Desktop)

MCP Tools

This server provides the following tool for Claude Desktop:

search_certificates

Search for SSL/TLS certificates in Certificate Transparency logs.

Parameters:

• domain (string, required): The domain to search for (e.g., "example.com")
• include_subdomains (boolean, optional, default: false): If true, search for certificates of all subdomains
• include_expired (boolean, optional, default: false): If true, include expired certificates in results
• limit (integer, optional, default: 100): Maximum number of results to return (1-1000)

Claude Desktop Integration

1. Configure Claude Desktop

Add this server to your Claude Desktop configuration file:

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

{
  "mcpServers": {
    "sslmate": {
      "command": "uv",
      "args": ["run", "/path/to/sslmate-mcp/sslmate_mcp.py"],
      "env": {
        "SSLMATE_API_KEY": "your-api-key-here"
      }
    }
  }
}

2. Restart Claude Desktop

Close and reopen Claude Desktop to load the new server.

3. Verify Integration

In Claude Desktop, you should now be able to ask questions like:

• "Search for certificates for example.com"
• "Find all subdomain certificates for github.com"
• "Show me expired certificates for my-domain.com"

Troubleshooting and Logging

Common Issues

Server not appearing in Claude Desktop:

1. Check the file path in claude_desktop_config.json
2. Ensure uv is installed and accessible
3. Verify the server starts manually: uv run sslmate_mcp.py

API rate limiting:

• Add your SSLMate API key to increase rate limits
• The free tier allows reasonable usage for most needs

No results returned:

• Try including subdomains: include_subdomains=true
• Try including expired certificates: include_expired=true
• Verify the domain name is correct

Logging

The server logs to stderr by default to maintain MCP protocol compliance. To enable file logging:

export LOG_TO_FILE=1
uv run sslmate_mcp.py

This creates a sslmate-mcp.log file in the current directory.

Testing the Server

Test the MCP protocol directly:

# Test basic functionality
python test_mcp_protocol.py

# Manual protocol test
echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}' | uv run sslmate_mcp.py

License

MIT. See LICENSE file for details.

SSLMate API

This project uses the SSLMate API. You'll need to obtain an API key from SSLMate to use this server.

For more information about the SSLMate API, visit: https://sslmate.com/api/