Core functions for Genarate OTP and Send Email

About NPM

Core utilities for OTP generation and sending secure login emails using Node.js and Nodemailer. Designed for MVC backends, Express apps, and password-less authentication flows.

✨ Features

• 🔐 Secure OTP generation

• 📧 Beautiful, production-ready OTP email template

• ⚡ Simple API (plug & play)

• 🧩 MVC-friendly (Controller → Service → Utility)

• 🔄 Reusable email sender

• 🚀 Works with Gmail SMTP (extensible)

🔧 Requirements

• Your host application must provide the following environment variables:

[email protected]
EMAIL_PASSWORD=your-app-password

• The package does NOT manage .env files — this is intentional and follows npm best practices

📁 Package Exports

const {
  defaultLoginOTPEmail,
  genarateOTP,
  sendEmail
} = require("otp-core-email-core");

| Function | Description | |------------------------|---------------------------------| | generateOTP(length) | Generates a secure one-time password (OTP) | | defaultLoginOTPEmail() | Sends a styled OTP login email | | sendEmail() | Low-level email sending utility |

🔐 Generate OTP

const { genarateOTP } = require("otp-core-email-core");

const otp = genarateOTP();      // default length: 8
const otp6 = genarateOTP(6);    // custom length

📧 Send OTP Login Email (Recommended)

• This is the main function of the package.

const { defaultLoginOTPEmail, genarateOTP } =
  require("otp-core-email-core");

const otp = genarateOTP();

await defaultLoginOTPEmail({
  email: "[email protected]",
  otp,
  project: "My Application"
});

What it does

• Uses a modern HTML email template

• Sends a password-less login OTP

• Displays project branding

• Explains OTP expiration and security

📨 Send Custom Email (Optional)

• You can also use the raw email sender.

const { sendEmail } = require("otp-core-email-core");

await sendEmail({
  project: "My App",
  to: "[email protected]",
  subject: "Welcome!",
  html: "<h1>Hello World</h1>"
});

🧱 MVC Example (Express Controller)

const {
  defaultLoginOTPEmail,
  genarateOTP
} = require("otp-core-email-core");

exports.sendLoginOTP = async (req, res) => {
  try {
    const { email } = req.body;

    if (!email) {
      return res.status(400).json({ message: "Email required" });
    }

    const otp = genarateOTP();

    await defaultLoginOTPEmail({
      email,
      otp,
      project: "MVC OTP App"
    });

    res.json({ message: "OTP sent successfully" });
  } catch (err) {
    console.error(err);
    res.status(500).json({ message: "Failed to send OTP" });
  }
};

🛡️ Security Notes

• OTPs are random and unpredictable

• Email explains expiration rules

• No passwords are stored

• Recommended to:

• • Store OTP hash in DB / Redis
• • Add rate-limiting on OTP requests

🧠 Design Decisions

• No global variables

• No framework coupling

• No .env handling inside library

• Clean separation of concerns

• Ready for production & scaling

📄 License

MIT License

👨‍💻 Author

• Jehan Weerasurit