Node.js Sendmail Utility

The `sendmail` package for Node.js provides a direct method for sending emails without relying on an external SMTP server. Instead, it resolves MX records for recipient domains and attempts to deliver mail directly. The current stable version is 1.6.1, though development appears to have ceased, with the last significant update converting to ES2015 in version 1.2.0. This library uses `mailcomposer` internally to handle email formatting, supporting HTML content, attachments, and DKIM signing. It also features a development mode for local testing without sending actual emails. Its primary differentiator is the direct delivery approach, contrasting with libraries that typically require SMTP relay configuration, making it suitable for specific application architectures or testing scenarios where a full SMTP setup is not desired.