Smtping MCP Server

SMTPing MCP server

Official Model Context Protocol server for SMTPing. It lets Claude, Cursor, VS Code, Windsurf and any MCP client verify email addresses in a conversation.

"Verify these 40 leads and tell me which ones are safe to email."

Remote server (no install)

Prefer not to run Node? Add https://mcp.smtping.com/mcp as a custom connector in Claude (Settings > Connectors) or ChatGPT, then sign in with your SMTPing API key. Same 5 tools, OAuth 2.1, nothing stored on the server. Source: smtping/smtping-mcp-remote.

Tools

Setup

Create an API key in the SMTPing dashboard, then add the server to your client. Node 18 or later is required.

Claude Desktop

Settings > Developer > Edit Config, then add to claude_desktop_config.json:

{
  "mcpServers": {
    "smtping": {
      "command": "npx",
      "args": ["-y", "@smtping/mcp"],
      "env": { "SMTPING_API_KEY": "sk_live_your_key_here" }
    }
  }
}

Restart Claude Desktop.

Claude Code

claude mcp add smtping -e SMTPING_API_KEY=sk_live_your_key_here -- npx -y @smtping/mcp

Cursor

~/.cursor/mcp.json (or .cursor/mcp.json in a project): same JSON block as Claude Desktop.

VS Code

.vscode/mcp.json:

{
  "servers": {
    "smtping": {
      "command": "npx",
      "args": ["-y", "@smtping/mcp"],
      "env": { "SMTPING_API_KEY": "sk_live_your_key_here" }
    }
  }
}

Windows troubleshooting

npx is not found: use "command": "cmd" and "args": ["/c", "npx", "-y", "@smtping/mcp"].

"Request timed out" or "Server disconnected" on first start: the first npx run downloads the package and can take longer than the client's 60 second startup limit. Install the server once, then point the client to it:

1. In a terminal: npm install -g @smtping/mcp
2. Replace the smtping block with:

"smtping": {
  "command": "node",
  "args": ["C:\\Users\\YOUR_NAME\\AppData\\Roaming\\npm\\node_modules\\@smtping\\mcp\\index.js"],
  "env": { "SMTPING_API_KEY": "sk_live_your_key_here" }
}

Replace YOUR_NAME with your Windows user folder (spaces are fine) and use double backslashes. Run echo %APPDATA% to see the exact path. This form also avoids issues with .cmd launchers when the user folder contains a space.

1. Quit the client completely (tray icon > Quit) and reopen it.

To update later: npm install -g @smtping/mcp@latest.

Logs: Claude Desktop writes them to %APPDATA%\Claude\logs\mcp-server-smtping.log.

Privacy

Addresses are sent to the SMTPing API only when a tool is called. See the privacy policy.

Links

• MCP page
• API documentation
• Pricing
• Support: support@smtping.com
• Blog: SMTPedia

MIT License