nodemailer

What is nodemailer?

Nodemailer is a module for Node.js applications to allow easy email sending. It supports various transport methods and has a simple setup process for sending emails.

What are nodemailer's main functionalities?

Send Emails

This feature allows you to send emails using Nodemailer. The code sample shows how to set up a transporter using Gmail, define mail options, and send an email.

const nodemailer = require('nodemailer');

let transporter = nodemailer.createTransport({
  service: 'gmail',
  auth: {
    user: '[e-mail]',
    pass: 'yourpassword'
  }
});

let mailOptions = {
  from: '[e-mail]',
  to: '[e-mail]',
  subject: 'Test Email Subject',
  text: 'Hello world?',
  html: '<b>Hello world?</b>'
};

transporter.sendMail(mailOptions, function(error, info){
  if (error) {
    console.log(error);
  } else {
    console.log('Email sent: ' + info.response);
  }
});

HTML Email Content

Nodemailer allows you to send HTML content in your emails. The code sample demonstrates how to send an email with HTML content.

const nodemailer = require('nodemailer');

let transporter = nodemailer.createTransport({
  // transport configuration
});

let mailOptions = {
  from: '[e-mail]',
  to: '[e-mail]',
  subject: 'HTML Email',
  html: '<h1>Welcome</h1><p>That was easy!</p>'
};

transporter.sendMail(mailOptions, function(error, info){
  // callback
});

Attachments

Nodemailer supports sending attachments in emails. The code sample shows how to attach a file to an email.

const nodemailer = require('nodemailer');

let transporter = nodemailer.createTransport({
  // transport configuration
});

let mailOptions = {
  from: '[e-mail]',
  to: '[e-mail]',
  subject: 'Attachment',
  text: 'Please find the attachment.',
  attachments: [
    {
      filename: 'file.txt',
      path: '/path/to/file.txt'
    }
  ]
};

transporter.sendMail(mailOptions, function(error, info){
  // callback
});

Custom Transport Methods

Nodemailer allows the use of custom transport methods for sending emails. The code sample illustrates how to use a custom transport plugin.

const nodemailer = require('nodemailer');
const customTransport = require('my-custom-transport');

let transporter = nodemailer.createTransport(customTransport({
  // custom transport options
}));

// send mail with defined transport object
transporter.sendMail({
  // mail options
}, function(error, info){
  // callback
});

Other packages similar to nodemailer

mailgun-js

A simple Node.js module for Mailgun. Mailgun-js is designed to work with the Mailgun API for sending, receiving, and tracking emails. It's similar to Nodemailer in functionality but is specifically tailored for Mailgun's service.

postmark

The official Node.js client library for interacting with the Postmark API. This package is intended for sending emails through Postmark's transactional email service. Unlike Nodemailer, which is more generic, Postmark is focused on providing a robust service for transactional emails.

aws-sdk

Amazon Web Services SDK for JavaScript in Node.js. It includes support for SES (Simple Email Service), which can be used to send emails. While Nodemailer is a standalone package for email, aws-sdk is a comprehensive cloud services SDK that includes email sending capabilities among many other AWS services.

README

Nodemailer

Nodemailer is an easy to use module to send e-mails with Node.JS.

You can use two ways to send an e-mail message: the EmailMessage constructor or the shortcut function send_mail(). The send_mail() function takes all the fields of the e-mail message as a function parameter and sends the e-mail immediately. EmailMessage allows to compose the message object first and send it later with its method send().

Nodemailer is Unicode friendly ✔. You can use any characters you like.

Installation

Install through NPM

npm install nodemailer

or download ZIP archive.

The source for Nodemailer is available at GitHub.

If you use NPM then the module is available as

var nodemailer = require('nodemailer');

but if you're using the source then

var nodemailer = require('./path_to_nodemailer/lib/mail');

Usage

Using send_mail()

var nodemailer = require("nodemailer");

nodemailer.send_mail({sender: "[e-mail]", 
                      to:"[e-mail]",
                      subject:"Hello!",
                      body:"Hi, how are you doing?"},
                      function(error, success){
                          console.log("Message "+(success?"sent":"failed"));
                      });
                      

Using EmailMessage

var nodemailer = require("nodemailer");

var mail = nodemailer.EmailMessage({
                      sender: "[e-mail]", 
                      to:"[e-mail]"
                      });
mail.subject = "Hello!";
mail.body = "Hi, how are you doing?";

mail.send(function(error, success){
              console.log("Message "+(success?"sent":"failed"));
          });

The callback function gets two parameters - error and success. If there's an error, then sending failed and you should check where's the problem. If there's no error value but success is not true then the server wasn't able to process the message correctly. Probably there was timeout while processing the message etc - in this case you should re-schedule sending this e-mail. If success is true then the message was sent successfully.

NB!

Before sending e-mails you need to set up SMTP server parameters.

nodemailer.SMTP = {
    host: "smtp.example.com",
    port: 25,
    hostname: "myhost.com",
    use_authentication: false,
    user: "",
    pass: ""
}

See examples/example.js for a complete example.

E-mail Message Fields

The following are the possible fields of an e-mail message:

• sender - The e-mail address of the sender. All e-mail addresses can be plain [e-mail] or formatted Sender Name <[e-mail]>
• to - Comma separated list of recipients e-mail addresses that will appear on the To: field
• cc - Comma separated list of recipients e-mail addresses that will appear on the Cc: field
• bcc - Comma separated list of recipients e-mail addresses that will appear on the Bcc: field
• reply_to - An e-mail address that will appear on the Reply-To: field
• subject - The subject of the e-mail
• body - The plaintext version of the message
• html - The HTML version of the message
• attachments - An array of attachment objects. Attachment object consists of two properties - filename and contents. Property contents can either be a String or a Buffer (for binary data). filename is the name of the attachment.

There's an optional extra field headers which holds custom header values in the form of {key: value}. These values will not overwrite any existing header but will be appended to the list.

mail_data = {
    sender:"[e-mail]",
    to:"[e-mail]",
    ....
    headers: {
        'X-My-Custom-Header-Value': 'Visit www.example.com for more info!'
    }
}

Address Formatting

All the e-mail addresses can be plain e-mail address

[e-mail]

or with formatted name (includes unicode support)

"Ноде Майлер" <[e-mail]>

To, Cc and Bcc fields accept comma separated list of e-mails. Formatting can be mixed.

[e-mail], "Ноде Майлер" <[e-mail]>, User Name <[e-mail]>

Currently you can't use comma in a formatted name, even if the name is in quotes.

Creating HTML messages

Message body in HTML format can be set with the message field html. If property html has contents but plain text alternative body has not (is left to empty), then existing text from the html version is also used in the plaintext version (without the html formatting).

The charset for html is UTF-8.

nodemailer.send_mail({
    ...
    html: "<p>hello world!<br/>хелло ворлд!</p>"
});

Using Attachments

An e-mail message can include one or several attachments. Attachments can be set with the message field attachments which accepts a list of attachment objects.

An attachment object primarly consists of two properties - filename which is the name of the file (not a filepath to an actual file on disk etc.) that will be reported to the receiver as the attachments name; and contents to hold the data in a String or Buffer format. There's an additional property cid which can be used for embedding images in a HTML message.

Property filename is unicode safe.

var attachment_list = [
    {
        "filename": "attachment1.txt",
        "contents": "contents for attachment1.txt"
    },
    {
        "filename": "аттачмент2.bin",
        "contents": new Buffer("binary contents", "binary");
    }
];

nodemailer.send_mail({
    ...
    attachments: attachment_list
});

Using Embedded Images

Attachments can be used as embedded images in the HTML body. To use this feature, you need to set additional property of the attachment - cid (unique identifier of the file) which is a reference to the attachment file. The same cid value must be used as the image URL in HTML (using cid: as the URL protocol, see example below).

NB! the cid value should be as unique as possible!

var cid_value = Date.now()+".image.jpg";
var html = 'Embedded image: <img src="cid:'+cid_value+'" />';
var attachments = [{
    filename: "image.png",
    contents: IMAGE_CONTENTS,
    cid: cid_value
}];

Issues

Use Nodemailer Issue tracker to report additional shortcomings, bugs, feature requests etc.

TLS

Node.JS v0.3.x doesn't support changing to a secure channel in the middle of a connection (STARTTLS). So when a server requires authentication and this must be done over TLS it's a problem.

Charsets

Currently the only allowed charset is UTF-8.

Attachments

Do not use large attachments as the attachment contents are read into memory and the final message body is combined into one large string before sending.

License

Nodemailer is licensed under MIT license. Basically you can do whatever you want to with it.