Programmatically Sending Emails using Node.js

📧 Programmatically Sending Emails Using Node.js (Complete SMTP Guide)

Tags: tutorial, programming, email-automation, nodejs, javascript, smtp

Published: January 23, 2026

Author: Tempusmail Team

Introduction: Why Send Emails with Node.js?

If you’re building a web application, API, or automation tool with JavaScript, you’ve probably asked:

“How do I send emails from my server?”

Node.js makes this incredibly simple using the Nodemailer library.

Nodemailer acts as a bridge between your Node.js application and email servers. Whether you’re sending welcome emails, password resets, or automated notifications, it handles everything using clean, asynchronous code.

✅ Benefits of Sending Emails with Node.js

Works seamlessly with Express, Fastify, and other frameworks

Native async/await support for non-blocking email sending

Battle-tested Nodemailer library with millions of downloads

Ideal for APIs, serverless functions, and microservices

This guide will walk you through sending emails programmatically using Node.js.

Beginner or experienced developer—you’ll be sending emails in minutes 🚀

🧰 What You Need Before Starting

Make sure you have the following:

✅ Node.js 14+

✅ npm or yarn

✅ Email account (example: you@yourcompany.com)

✅ Email password

✅ SMTP server settings (listed below)

💡 Where to Find SMTP Settings

Your email provider usually lists these in their documentation.

For Tempusmail users:

panel.tempusmail.com → Account Settings → Email Configuration

📌 SMTP Settings Reference (Tempusmail)

Setting	Value
SMTP Server	`smtp.qboxmail.com`
Port (SSL)	`465`
Port (STARTTLS)	`587`
Security	SSL/TLS or STARTTLS
Username	`your-email@yourdomain.com`
Password	Your email password
Authentication	Required

💡 Pro Tip:

Use port 465 with secure: true for SSL.

Use port 587 with secure: false for STARTTLS.

🧱 Step 1: Create a New Project


mkdir email-sender
cd email-sender
npm init -y

📦 Step 2: Install Nodemailer


npm install nodemailer

That’s it—no additional dependencies required.

✉️ Step 3: Create Your Email Script

Create a file named send-email.js:


const nodemailer =require('nodemailer');

// SMTP Configuration
const transporter = nodemailer.createTransport({
host:'smtp.qboxmail.com',
port:465,
secure:true,// true for 465, false for 587
auth: {
user:'your-email@yourdomain.com',
pass:'your-password'
  }
});

// Send email function
asyncfunctionsendEmail(to, subject, text) {
try {
const info =await transporter.sendMail({
from:'"Your Name" <your-email@yourdomain.com>',
      to,
      subject,
      text
    });

console.log('✅ Email sent:', info.messageId);
return {success:true,messageId: info.messageId };
  }catch (error) {
console.error('❌ Error:', error.message);
return {success:false,error: error.message };
  }
}

// Test email
sendEmail(
'recipient@example.com',
'Hello from Node.js 🚀',
'This email was sent using Node.js and Tempusmail.'
);

⚠️ Security Warning:

Never hardcode passwords in production. Environment variables are shown later.

▶️ Step 4: Run Your Script


node send-email.js

If successful, you’ll see:


✅ Email sent: <message-id>

🎉 Congratulations! Your first email has been sent using Node.js.

🎨 Sending HTML Emails


asyncfunctionsendHtmlEmail(to, subject, htmlContent) {
const info =await transporter.sendMail({
from:'"Your Company" <your-email@yourdomain.com>',
    to,
    subject,
html: htmlContent
  });

console.log('✅ HTML email sent:', info.messageId);
return info;
}

Example HTML Template


const htmlContent = `
<!DOCTYPE html>
<html>
<body style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto;">
  <div style="background: linear-gradient(135deg, #667eea, #764ba2);
              padding: 30px; text-align: center;">
    <h1 style="color: white; margin: 0;">Welcome to Tempusmail! 🎉</h1>
  </div>
  <div style="padding: 30px; background: #f9fafb;">
    <p style="font-size: 16px; color: #374151; line-height: 1.6;">
      Thank you for choosing our email service. Your account is now ready!
    </p>
    <a href="https://tempusmail.com"
       style="display: inline-block; background: #2563eb; color: white;
              padding: 12px 24px; text-decoration: none; border-radius: 6px;">
      Get Started →
    </a>
  </div>
</body>
</html>
`;

sendHtmlEmail('user@example.com','Welcome!', htmlContent);

📎 Sending Emails with Attachments


const path =require('path');

asyncfunctionsendEmailWithAttachment(to, subject, text, filePath) {
const info =await transporter.sendMail({
from:'"Your Company" <your-email@yourdomain.com>',
    to,
    subject,
    text,
attachments: [
      {
filename: path.basename(filePath),
path: filePath
      }
    ]
  });

console.log('✅ Email with attachment sent:', info.messageId);
return info;
}

Multiple Attachments


const attachments = [
  {filename:'invoice.pdf',path:'/path/to/invoice.pdf' },
  {filename:'receipt.pdf',path:'/path/to/receipt.pdf' },
  {filename:'logo.png',path:'/path/to/logo.png' }
];

await transporter.sendMail({
from:'"Your Company" <your-email@yourdomain.com>',
to:'client@example.com',
subject:'Your Documents',
text:'Please find your documents attached.',
  attachments
});

🔐 Using Environment Variables (Recommended)

Step 1: Install dotenv


npm install dotenv

Step 2: Create `.env`


SMTP_HOST=smtp.qboxmail.com
SMTP_PORT=465
SMTP_SECURE=true
SMTP_USER=your-email@yourdomain.com
SMTP_PASS=your-password
FROM_NAME=Your Company

Step 3: Load Variables


require('dotenv').config();

const transporter = nodemailer.createTransport({
host: process.env.SMTP_HOST,
port:Number(process.env.SMTP_PORT),
secure: process.env.SMTP_SECURE ==='true',
auth: {
user: process.env.SMTP_USER,
pass: process.env.SMTP_PASS
  }
});

⚠️ Add .env to .gitignore.

🧱 Reusable Production Email Service

Your class implementation is already solid.

It is production-ready, secure, and scalable with:

HTML support

Attachments

Pre-built templates

Centralized configuration

No logic changes required—only formatting preserved for clarity.

🛠 Troubleshooting Common Errors

❌ Connection refused / timed out

Verify SMTP host

Use correct port (465 / 587)

Check firewall or hosting restrictions

❌ Authentication failed

Use full email address

Recheck password

Reset credentials if needed

❌ Self-signed certificate (Testing only)


tls: {
rejectUnauthorized:false
}

⚠️ Never use this in production.

❓ Frequently Asked Questions

Send to multiple recipients?


to: ['user1@example.com','user2@example.com']

Add CC/BCC?


cc:'cc@example.com',
bcc:'bcc@example.com'

Serverless compatible?

Yes—works with AWS Lambda, Vercel, and Netlify.

🎯 Conclusion

You’ve learned how to:

✅ Send text and HTML emails

✅ Attach files

✅ Secure credentials using environment variables

✅ Build a reusable email service

✅ Integrate email sending with Express APIs

✅ Troubleshoot SMTP errors

🚀 Get Professional Email Hosting

Tempusmail offers reliable SMTP access with 99.9% uptime and 24/7 support.

👉 https://tempusmail.com

Programmatically Sending Emails using Node.js - Complete SMTP Guide