How it works

Add Mailtrap’s MCP server to Windsurf and use the Cascade AI assistant to send emails, manage templates, monitor deliverability and assist with domain setup – without leaving your editor. 

Beyond the MCP connection, Cascade can also scaffold Mailtrap SDK integrations into your project code.

Configuration

Step 1: Create an account and get the API key

Navigate to Settings → API Tokens and click on Add Token. 

Step 2: Add Mailtrap MCP to Windsurf

Open Windsurf, navigate to Settings → Windsurf Settings → Cascade and open the MCP Marketplace.

On the MCP Marketplace page, click on the Cogwheel button, which will open the mcp.config.json file.

Next, in the mcp.config.json file, copy/paste the following code snippet:

{
  "mcpServers": {
    "mailtrap": {
      "command": "npx",
      "args": ["-y", "mcp-mailtrap"],
      "env": {
        "MAILTRAP_API_TOKEN": "your_mailtrap_api_token",
        "DEFAULT_FROM_EMAIL": "your_sender@example.com",
        "MAILTRAP_ACCOUNT_ID": "your_account_id",
        "MAILTRAP_TEST_INBOX_ID": "your_test_inbox_id"
      }
    }
  }
}

Step 3: Insert your Mailtrap credentials

Replace the placeholders in mcp_config.json with your:

• MAILTRAP_API_TOKEN – Required for all operations.
• DEFAULT_FROM_EMAIL – Must match the domain from your Sending Domains.
• MAILTRAP_ACCOUNT_ID – Required for template management.
• MAILTRAP_TEST_INBOX_ID – Required for Sandbox features.

Make sure to refresh the page or restart Windsurf for the changes to take effect.

Use cases

• Send a test email mid-development and verify it lands in your sandbox inbox, without switching to a browser.
• Iterate email template copies through Cascade prompts – create, send to sandbox, review, update.
• Trigger transactional emails from your project and confirm delivery in Mailtrap Email Logs.
• Fetch recent sandbox messages to inspect and debug emails during coding sessions.
• Scaffold email infrastructure in a new project and debug delivery issues without switching windows.

For more information, please consult the official knowledge base article.