Sending Emails with Nodemailer in Node.js

Are you looking to add email functionality to your Node.js application? Whether you're building a contact form, sending notifications, or automating email workflows, this tutorial is your ultimate guide to getting started. Using Nodemailer, a powerful and easy-to-use Node.js library, we'll walk you through every step of sending emails programmatically. From setting up your project to sending emails with attachments, this tutorial is designed to be beginner-friendly while covering advanced features for seasoned developers.

By the end of this tutorial, you'll have a fully functional email-sending system integrated into your Node.js application. You'll also learn best practices like securing your credentials with environment variables and testing your setup with a fake SMTP server. Ready to take your Node.js skills to the next level? Dive into the tutorial and start sending emails like a pro today!

Prerequisites

Before starting, ensure you have the following:

• Node.js installed on your machine (read here how to do it).
• A Gmail account (or any other email service provider) for sending emails.
• Basic knowledge of JavaScript and Node.js.

Step 1: Set Up Your Node.js Project

1. Create a new directory for your project:

mkdir nodemailer-tutorial
cd nodemailer-tutorial

2. Initialize a new Node.js project:

npm init -y

3. Install the Nodemailer library:

npm install nodemailer --save

Step 2: Configure Nodemailer

Nodemailer requires a transport object to send emails. For this tutorial, we'll use Gmail as the email service provider.

1. Create a new file called index.js:

touch index.js

2. Open the file and add the following code to set up Nodemailer:

1// Step 1: Import Nodemailer
2const nodemailer = require('nodemailer');
3
4// Step 2: Create a transporter object
5const transporter = nodemailer.createTransport({
6    service: 'gmail', // Use Gmail as the service
7    auth: {
8        user: '[email protected]', // Your Gmail address
9        pass: 'your-app-password', // Your Gmail app password (not your regular password)
10    },
11});
12
13// Step 3: Define email options
14const mailOptions = {
15    from: '[email protected]', // Sender address
16    to: '[email protected]', // Recipient address
17    subject: 'Hello from Nodemailer!', // Email subject
18    text: 'This is a test email sent using Nodemailer.', // Plain text body
19    html: '<h1>Hello!</h1><p>This is a test email sent using <b>Nodemailer</b>.</p>', // HTML body
20};
21
22// Step 4: Send the email
23transporter.sendMail(mailOptions, (error, info) => {
24    if (error) {
25        console.error('Error sending email:', error);
26    } else {
27        console.log('Email sent:', info.response);
28    }
29});

Step 3: Generate an App Password for Gmail

Since Gmail requires additional security for third-party apps, you'll need to generate an app password:

• Go to your Google Account settings: https://myaccount.google.com.
• Enable 2-Step Verification if it's not already enabled.
• Generate an app password:
  • Go to Security > App Passwords.
  • Select Mail as the app and Other as the device.
  • Copy the generated password and use it in the auth.pass field in the code above.

Step 4: Run the Code

• Save the index.js file.
• Run the script using Node.js:

  node index.js

• If everything is set up correctly, you should see a success message like:

  Email sent: 250 2.0.0 OK  1234567890abcdef-1234567890abcdef

• Check the recipient's inbox for the email.

Step 5: Sending Emails with Attachments

You can also send emails with attachments using Nodemailer. Update the mailOptions object as follows:

1const mailOptions = {
2    from: '[email protected]',
3    to: '[email protected]',
4    subject: 'Email with Attachment',
5    text: 'This email contains an attachment.',
6    html: '<h1>Check this out!</h1><p>This email contains an attachment.</p>',
7    attachments: [
8        {
9            filename: 'example.txt', // Name of the attachment
10            content: 'This is a text file attachment.', // Content of the attachment
11        },
12        {
13            filename: 'image.png', // Name of the image attachment
14            path: __dirname + '/image.png', // Path to the image file
15        },
16    ],
17};

Step 6: Using Environment Variables

For security reasons, avoid hardcoding sensitive information like email credentials. Use environment variables instead:

• Install the dotenv package:

  npm install dotenv

• Create a .env file:

  touch .env

• Add your credentials to the .env file:

  EMAIL_USER=[email protected]
  EMAIL_PASS=your-app-password

• Update index.js to use environment variables:

  1require('dotenv').config();
  2
  3const transporter = nodemailer.createTransport({
  4    service: 'gmail',
  5    auth: {
  6        user: process.env.EMAIL_USER,
  7        pass: process.env.EMAIL_PASS,
  8    },
  9});

Step 7: Testing with a Fake SMTP Server

If you don't want to use a real email account, you can test your code using a fake SMTP server like Mailtrap:

• Sign up for a free account at Mailtrap.
• Update the transporter configuration:

1const transporter = nodemailer.createTransport({
2    host: 'sandbox.smtp.mailtrap.io',
3    port: 2525,
4    auth: {
5        user: 'your-mailtrap-username',
6        pass: 'your-mailtrap-password',
7    },
8});

Conclusion

You've successfully learned how to send emails using Node.js and Nodemailer! You can now:

• Send plain text and HTML emails.
• Add attachments to your emails.
• Use environment variables for secure credential management.
• Test your code with a fake SMTP server.

Feel free to explore Nodemailer's official documentation for more advanced features like templates, custom SMTP servers, and more.