Mailcub — Node.js SDK to send transactional emails and newsletters from your own domain using the MailCub email API.

Mailcub is a lightweight Node.js package for sending HTML or plain‑text emails and attachments from your own domain via the MailCub email API. It’s built for transactional emails, app notifications, and simple newsletters without managing SMTP servers yourself.

Installation

npm install mailcub

Quick example (30-second demo)

const mailcub = require('mailcub');

const emailBody = {
  email_from: '[email protected]',
  receiver: '[email protected]',
  subject: 'Welcome',
  html: '<h1>Hello!</h1><p>Thanks for signing up.</p>'
};

mailcub.sendMail(emailBody, 'your-secret-key')
  .then(() => console.log('Email sent'))
  .catch(err => console.error('Error:', err));

Get your secret key at mailcub.com.

Full API & options

sendMail(body, key)

Sends an email. Returns a Promise.

| Parameter | Type | Description | |-----------|------|-------------| | body | Object | Email payload (see below). | | key | String | Secret key for authentication. From mailcub.com. |

body object

| Field | Type | Required | Description | |-------|------|----------|-------------| | email_from | string | Yes | Sender email (use an address on your registered domain). | | receiver | string | Yes | Recipient email address. | | subject | string | Yes | Email subject line. | | html | string | No* | HTML body of the email. | | text | string | No* | Plain-text body of the email. Use html or text (or both). | | attachment | File or File[] | No | Single file or array of files (file objects only, not paths). |

*At least one of html or text is required.

Examples

Plain text only

mailcub.sendMail({
  email_from: '[email protected]',
  receiver: '[email protected]',
  subject: 'Order confirmation',
  text: 'Thank you for your order. Order #1234 has been received.'
}, process.env.MAILCUB_SECRET_KEY);

HTML only

mailcub.sendMail({
  email_from: '[email protected]',
  receiver: '[email protected]',
  subject: 'Order confirmation',
  html: '<h1>Order #1234</h1><p>Thank you for your order.</p>'
}, process.env.MAILCUB_SECRET_KEY);

With a single attachment

// attachment = file from request, Postman, etc.
mailcub.sendMail({
  email_from: '[email protected]',
  receiver: '[email protected]',
  subject: 'Your invoice',
  html: '<p>Please find your invoice attached.</p>',
  attachment
}, process.env.MAILCUB_SECRET_KEY);

With multiple attachments

// attachment = array of files (e.g. from request, Postman, etc.)
mailcub.sendMail({
  email_from: '[email protected]',
  receiver: '[email protected]',
  subject: 'Your documents',
  html: '<p>Attached are the requested files.</p>',
  attachment: [file1, file2]
}, process.env.MAILCUB_SECRET_KEY);

Using async/await

const mailcub = require('mailcub');

async function sendWelcomeEmail(to) {
  try {
    await mailcub.sendMail({
      email_from: '[email protected]',
      receiver: to,
      subject: 'Welcome',
      html: '<h1>Welcome!</h1>'
    }, process.env.MAILCUB_SECRET_KEY);
    return true;
  } catch (err) {
    console.error(err);
    return false;
  }
}

Why choose Mailcub?

• Simple API — One function, clear parameters; no SMTP or server config.
• Your domain — Send from your own domain for a professional, branded look.
• HTML or plain text — Send rich HTML or simple plain-text emails (or both).
• Attachments — Single or multiple file attachments.
• Secret-key auth — Secure authentication; keep your key in env vars.
• Lightweight — Minimal dependencies; fits into existing Node.js apps.
• Transactional & newsletters — Suited for both one-off emails and bulk sending.

Troubleshooting & FAQ

Where do I get the secret key?
Sign up and get your key at mailcub.com.

"Error sending email" or failed requests

• Ensure email_from uses a domain you’ve registered in Mailcub.
• Check that your secret key is correct and not expired.
• Verify receiver and subject are non-empty; include at least one of html or text.

Attachments not sending

• attachment must be file(s) (e.g. from request, Postman, or your app), not path strings.
• For multiple files, pass an array: attachment: [file1, file2].

Need help?
Contact [email protected] or open an issue: GitHub Issues.

Contributing & Code of Conduct

Contributions are welcome. Please open an issue or pull request on GitHub. Be respectful and constructive; we expect a courteous, inclusive environment for everyone.

License & Author

• License: ISC
• Author: Devflips
• Package: npm — mailcub · GitHub — mailcub