localSMTP

Local dummy SMTP server for development. It accepts messages and writes the original bytes to .eml files.

SMTP server

uv run localsmtp --host 127.0.0.1 --port 25 --out ./mail

The legacy entry point also works:

uv run python .\main.py --host 127.0.0.1 --port 25 --out ./mail

Related MCP server: mailsink

MCP server

The MCP entry point starts both the MCP stdio server and an SMTP listener. This lets coding agents start the mail catcher only when they need it.

uv run localsmtp-mcp --smtp-host 127.0.0.1 --smtp-port 25

By default, the MCP server stores received mail in a temporary directory. Pass --out when you want to keep messages in a specific location.

After publishing the package, use it from an MCP client with uvx:

{
  "mcpServers": {
    "localsmtp": {
      "command": "uvx",
      "args": [
        "--from",
        "git+https://github.com/fclef819/localSMTP-mcp.git",
        "localsmtp-mcp",
        "--smtp-host",
        "127.0.0.1",
        "--smtp-port",
        "25"
      ]
    }
  }
}

MCP tools

• list_messages(limit = 50, newest_first = true)

• get_message(id, include_raw = false)

• clear_messages()

• get_server_status()