Easy to use module to send e-mails with Node.JS
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Nodemailer is an easy to use module to send e-mails with Node.JS (using SMTP or sendmail or Amazon SES) and is unicode friendly - You can use any characters you like ✔

Nodemailer is Windows friendly, you can install it with npm on Windows just like any other module, there are no compiled dependencies. Use it from Azure or from your Windows box hassle free.

Read about using Nodemailer from the Node Knockout blog

Build Status NPM version

Notes and information

Nodemailer supports

  • Unicode to use any characters
  • HTML content as well as plain text alternative
  • Attachments (including attachment streaming for sending larger files)
  • Embedded images in HTML
  • SSL/STARTTLS for secure e-mail delivery
  • Different transport methods - SMTP, sendmail and Amazon SES
  • SMTP Connection pool and connection reuse for rapid delivery
  • Preconfigured services for using SMTP with Gmail, Hotmail etc.
  • Use objects as header values for SendGrid SMTP API
  • XOAUTH2 authentication and token generation support - useful with Gmail
  • DKIM signing

Support Nodemailer development

Donate to author

If you want to support with Bitcoins, then my wallet address is 15Z8ADxhssKUiwP3jbbqJwA21744KMCfTM

Nodemailer PaaS support

Nodemailer has been tested successfully on the following PaaS platforms (using free/trial accounts):

Check out my other mail related modules

If you want to parse generated or received e-mail instead of sending it, check out MailParser.

If you only want to generate the raw e-mail stream, check out MailComposer.

If you only want to communicate with the SMTP (both as client and the server), check out simplesmtp.


To use Nodemailer with templates, please see documentation for these projects.

TL;DR Usage Example

This is a complete example to send an e-mail with plaintext and HTML body

var nodemailer = require("nodemailer");

// create reusable transport method (opens pool of SMTP connections)
var smtpTransport = nodemailer.createTransport("SMTP",{
    service: "Gmail",
    auth: {
        user: "gmail.user@gmail.com",
        pass: "userpass"

// setup e-mail data with unicode symbols
var mailOptions = {
    from: "Fred Foo ✔ <foo@blurdybloop.com>", // sender address
    to: "bar@blurdybloop.com, baz@blurdybloop.com", // list of receivers
    subject: "Hello ✔", // Subject line
    text: "Hello world ✔", // plaintext body
    html: "<b>Hello world ✔</b>" // html body

// send mail with defined transport object
smtpTransport.sendMail(mailOptions, function(error, response){
        console.log("Message sent: " + response.message);

    // if you don't want to use this transport object anymore, uncomment following line
    //smtpTransport.close(); // shut down the connection pool, no more messages

See also the examples folder for full featured examples


Install through NPM

npm install nodemailer


Include the module

var nodemailer = require("nodemailer");

An e-mail can be sent with sendMail(mailOptions[, callback]) command

transport.sendMail(mailOptions, callback);


  • transport is a transport object created from the nodemailer.createTransport method
  • mailOptions defines the e-mail (set its subject, body text, receivers etc.), see E-mail Message Fields for details
  • callback is the callback function that will be run after the e-mail is sent or the sending failed (see Return callback for details)

Setting up a transport method

Before you can send any e-mails you need to set up a transport method. This can be done with nodemailer.createTransport(type, options) where type indicates the transport protocol and options defines how it is used.

var transport = nodemailer.createTransport("SMTP", {smtp_options});

The same transport object can and should be reused several times.

When the transport method is defined, it can be used to send e-mail with sendMail

var transport = nodemailer.createTransport("SMTP", {smtp_options});

    from: "sender@tr.ee",
    to: "receiver@tr.ee"

Possible transport methods

Required type parameter can be one of the following:

  • SMTP for using SMTP
  • SES for using Amazon SES
  • Sendmail for utilizing systems sendmail command

Setting up SMTP

SMTP is different from the other transport mechanisms, as in its case a connection pool is created. All the connections try to stay alive as long as possible and are reusable to minimize the protocol overhead delay - for example setting up TLS for authenticating is relatively lengthy process (in CPU terms, not by human terms), you do not want to do it several times.

Possible SMTP options are the following:

  • service - an optional well known service identifier ("Gmail", "Hotmail" etc., see Well known Services for a list of supported services) to auto-configure host, port and secure connection settings
  • host - hostname of the SMTP server (defaults to "localhost", not needed with service)
  • port - port of the SMTP server (defaults to 25, not needed with service)
  • secureConnection - use SSL (default is false, not needed with service). If you're using port 587 then keep secureConnection false, since the connection is started in insecure plain text mode and only later upgraded with STARTTLS
  • name - the name of the client server (defaults to machine name)
  • auth - authentication object as {user:"...", pass:"..."} or {XOAuth2: {xoauth2_options}} or {XOAuthToken: "base64data"}
  • ignoreTLS - ignore server support for STARTTLS (defaults to false)
  • debug - output client and server messages to console
  • maxConnections - how many connections to keep in the pool (defaults to 5)


var transport = nodemailer.createTransport("SMTP", {
    service: "Gmail",
    auth: {
        user: "gmail.user@gmail.com",
        pass: "userpass"

or the same without service parameter

var transport = nodemailer.createTransport("SMTP", {
    host: "smtp.gmail.com", // hostname
    secureConnection: true, // use SSL
    port: 465, // port for secure SMTP
    auth: {
        user: "gmail.user@gmail.com",
        pass: "userpass"

NB! if you want to close the pool (cancel all open connections) you can use transport.close()

var transport = nodemailer.createTransport("SMTP",{});
transport.close(); // close the pool

SMTP XOAUTH and token generation


nodemailer supports XOAUTH2 authentication protocol. To use this you need to obtain a Client ID and a Client Secret from Google API Console (Open "API Access" and create "Client ID for web applications") and then request a refresh token for an user. See Google OAuth 2.0 Offline Access for more information.

Once you have obtained the Client ID, Client Secret and a Refresh Token for an user, you can use these values to send mail on behalf of the user.

var transportOptions = {
    auth: {
        XOAuth2: {
            user: "example.user@gmail.com",
            clientId: "8819981768.apps.googleusercontent.com",
            clientSecret: "{client_secret}",
            refreshToken: "1/xEoDL4iW3cxlI7yDbSRFYNG01kVKM2C-259HOF2aQbI",
            accessToken: "vF9dft4qmTc2Nvb3RlckBhdHRhdmlzdGEuY29tCg==",
            timeout: 3600

accessToken and timeout values are both optional. If XOAUTH2 login fails a new access token is generated automatically and the login is retried.


Older XOAUTH is also supporteb by nodemailer for SMTP. XOAUTH is based on OAuth protocol 1.0 and is considered deprecated.

To use this, include XOAuthToken option in auth instead of the regular user and pass.

var transportOptions = {
    auth: {
        XOAuthToken: "R0VUIGh0dHBzOi8vbWFpbC5nb29...."

nodemailer includes also built in XOAUTH token generator which can be used with nodemailer.createXOAuthGenerator(). The function is preconfigured for Gmail, so in this case only mandatory options are user, token and tokenSecret.

var XOAuthTokenGenerator = nodemailer.createXOAuthGenerator({
        user: "test.nodemailer@gmail.com",
        // requestUrl: "https://oauth.access.point",
        // consumerKey: "anonymous",
        // consumerSecret: "anonymous",
        token: "1/O_HgoO4h2uOUfpus0V--7mygICXrQQ0ZajB3ZH52KqM",
        tokenSecret: "_mUBkIwNPnfQBUIWrJrpXJ0c"

One of user or requestUrl is mandatory. consumerKey and consumerSecret both default to "anonymous".

var transportOptions = {
    service: "Gmail",
    auth: {
        XOAuthToken: nodemailer.createXOAuthGenerator({
            user: "test.nodemailer@gmail.com",
            token: "1/O_HgoO4h2uOUfpus0V--7mygICXrQQ0ZajB3ZH52KqM",
            tokenSecret: "_mUBkIwNPnfQBUIWrJrpXJ0c"

Setting up SES

SES is actually a HTTP based protocol, the compiled e-mail and related info (signatures and such) are sent as a HTTP request to SES servers.

Possible SES options are the following:


var transport = nodemailer.createTransport("SES", {
    AWSSecretKey: "AWS/Secret/key"

Setting up Sendmail

Sendmail transport method streams the compiled message to the stdin of sendmail command.

Options object is optional, possible sendmail options are the following:

  • path - path to the sendmail command (defaults to "sendmail")
  • args - an array of extra command line options to pass to the sendmail command (ie. ["-f", "foo@blurdybloop.com"]).

Currently the command to be spawned is built up like this: the command is either using sendmail -i -f from_addr to_addr[] (by default) or sendmail -i list_of_args[] (if args property was given). -i is ensured to be present on either case.

In the default case (no args defined) From and To addresses are either taken from From,To, Cc and Bcc properties or from the envelope property if one is present.

Be wary when using the args property - no recipients are defined by default, you need to ensure these by yourself, for example by using the -t flag.


var transport = nodemailer.createTransport("sendmail");


var transport = nodemailer.createTransport("sendmail", {
    path: "/usr/local/bin/sendmail",
    args: ["-t", "-f", "foo@blurdybloop.com"]

DKIM Signing

Nodemailer supports DKIM signing with very simple setup. Use this with caution though since the generated message needs to be buffered entirely before it can be signed. Not a big deal with small messages but might consume a lot of RAM when using larger attachments.

Set up the DKIM signing with useDKIM method for a transport object:


Where dkimOptions includes necessary options for signing

  • domainName - the domainname that is being used for signing
  • keySelector - key selector. If you have set up a TXT record with DKIM public key at zzz._domainkey.blurdybloop.com then zzz is the selector
  • privateKey - DKIM private key that is used for signing as a string
  • headerFieldNames - optional colon separated list of header fields to sign, by default all fields suggested by RFC4871 #5.5 are used

All messages transmitted through this transport objects are from now on DKIM signed.

Currently if several header fields with the same name exists, only the last one (the one in the bottom) is signed.


var transport = nodemailer.createTransport("Sendmail");

    domainName: "kreata.ee",
    keySelector: "dkim",
    privateKey: fs.readFileSync("private_key.pem")


See examples/example_dkim.js for a complete example.

Well known services for SMTP

If you want to use a well known service as the SMTP host, you do not need to enter the hostname or port number, just use the service parameter

Currently supported services are:

  • DynectEmail
  • Gmail
  • hot.ee
  • Hotmail
  • iCloud
  • mail.ee
  • Mail.Ru
  • Mailgun
  • Mailjet
  • Mandrill
  • Postmark
  • QQ
  • SendGrid
  • SES
  • Yahoo
  • yandex
  • Zoho

Predefined service data covers host, port and secure connection settings, any other parameters (ie. auth) need to be set separately. Service names are case insensitive, so using "gmail" instead of "Gmail" is totally fine.


var smtpTransport = nodemailer.createTransport("Gmail",{
    auth: {
        user: "gmail.user@gmail.com",
        pass: "userpass"

or alternatively

var smtpTransport = nodemailer.createTransport("SMTP",{
    service: "Gmail", // sets automatically host, port and connection security settings
    auth: {
        user: "gmail.user@gmail.com",
        pass: "userpass"

Actually, if you are authenticatinw with an e-mail address that has a domain name like @gmail.com or @yahoo.com etc., then you don't even need to provide the service name, it is detected automatically.

var smtpTransport = nodemailer.createTransport("SMTP",{
    auth: {
        user: "gmail.user@gmail.com", // service is detected from the username
        pass: "userpass"

E-mail message fields

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

  • from - The e-mail address of the sender. All e-mail addresses can be plain sender@server.com or formatted Sender Name <sender@server.com>
  • to - Comma separated list or an array of recipients e-mail addresses that will appear on the To: field
  • cc - Comma separated list or an array of recipients e-mail addresses that will appear on the Cc: field
  • bcc - Comma separated list or an array of recipients e-mail addresses that will appear on the Bcc: field
  • replyTo - An e-mail address that will appear on the Reply-To: field
  • inReplyTo - The message-id this message is replying
  • references - Message-id list
  • subject - The subject of the e-mail
  • text - The plaintext version of the message
  • html - The HTML version of the message
  • generateTextFromHTML - if set to true uses HTML to generate plain text body part from the HTML if the text is not defined
  • headers - An object of additional header fields {"X-Key-Name": "key value"} (NB! values are passed as is, you should do your own encoding to 7bit and folding if needed)
  • attachments - An array of attachment objects.
  • alternatives - An array of alternative text contents (in addition to text and html parts)
  • envelope - optional SMTP envelope, if auto generated envelope is not suitable
  • messageId - optional Message-Id value, random value will be generated if not set. Set to false to omit the Message-Id header
  • date - optional Date value, current UTC string will be used if not set
  • encoding - optional transfer encoding for the textual parts (defaults to "quoted-printable")
  • charset - optional output character set for the textual parts (defaults to "utf-8")

All text fields (e-mail addresses, plaintext body, html body) use UTF-8 as the encoding. Attachments are streamed as binary.


var transport = nodemailer.createTransport("Sendmail");

var mailOptions = {
    from: "me@tr.ee",
    to: "me@tr.ee",
    subject: "Hello world!",
    text: "Plaintext body"


SendGrid support

Nodemailer supports SendGrid SMTP API out of the box - you can use objects as header values and these are automatically JSONized (and mime encoded if needed).

var mailOptions = {
    headers: {
        'X-SMTPAPI': {
            category : "newuser",
                "%name%": ["Žiguli Õllepruul"]
    subject: "Hello, %name%"

This also applies to any other service that expects a JSON string as a header value for specified key.

Generate Text from HTML

If generateTextFromHTML option is set to true, then HTML contents of the mail is automatically converted to plaintext format when plaintext content is empty or missing.

For example

mailOptions = {
    generateTextFromHTML: true,
    html: '<h1>Hello world</h1><p><b>How</b> are you?',
    // text: '' // no text part

is automatically converted in the backround by Nodemailer to:

mailOptions = {
    // source html:
    html: '<h1>Hello world</h1><p><b>How</b> are you?',
    // automatically generated plaintext message:
    text: "Hello world\n"+
          "**How** are you?"

As you can see the output syntax for generateTextFromHTML looks similar to markdown, and that is exactly the case here - Nodemailer includes a simple HTML to markdown converter. But don't expect too much from it, it's not full featured or perfect, just some regexes here and there.

Attachment fields

Attachment object consists of the following properties:

  • fileName - filename to be reported as the name of the attached file, use of unicode is allowed (except when using Amazon SES which doesn't like it)
  • cid - optional content id for using inline images in HTML message source
  • contents - String or a Buffer contents for the attachment
  • filePath - path to a file or an URL if you want to stream the file instead of including it (better for larger attachments)
  • streamSource - Stream object for arbitrary binary streams if you want to stream the contents (needs to support pause/resume)
  • contentType - optional content type for the attachment, if not set will be derived from the fileName property
  • contentDisposition - optional content disposition type for the attachment, defaults to "attachment"

One of contents, filePath or streamSource must be specified, if none is present, the attachment will be discarded. Other fields are optional.

Attachments can be added as many as you want.

var mailOptions = {
    attachments: [
        {   // utf-8 string as an attachment
            fileName: "text1.txt",
            contents: "hello world!"
        {   // binary buffer as an attachment
            fileName: "text2.txt",
            contents: new Buffer("hello world!","utf-8")
        {   // file on disk as an attachment
            fileName: "text3.txt",
            filePath: "/path/to/file.txt" // stream this file
        {   // fileName and content type is derived from filePath
            filePath: "/path/to/file.txt"
        {   // stream as an attachment
            fileName: "text4.txt",
            streamSource: fs.createReadStream("file.txt")
        {   // define custom content type for the attachment
            fileName: "text.bin",
            contents: "hello world!",
            contentType: "text/plain"
        {   // use URL as an attachment
            fileName: "license.txt",
            filePath: "https://raw.github.com/andris9/Nodemailer/master/LICENSE"

Alternative fields

In addition to text and HTML, any kind of data can be inserted as an alternative content of the main body - for example a word processing document with the same text as in the HTML field. It is the job of the e-mail client to select and show the best fitting alternative to the reader.

Attahcment object consists of the following properties:

  • contents - String or a Buffer contents for the attachment
  • contentType - optional content type for the attachment, if not set will be set to "application/octet-stream"
  • contentEncoding - optional value of how the data is encoded, defaults to "base64"

If contents is empty, the alternative will be discarded. Other fields are optional.

Usage example:

var mailOptions = {
    html: "<b>Hello world!</b>",
    alternatives: [
            contentType: "text/x-web-markdown",
            contents: "**Hello world!**"

If the receiving e-mail client can render messages in Markdown syntax as well, it could prefer to display this alternative as the main content of the message instead of the html part.

Alternatives can be added as many as you want.

Address Formatting

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


or with formatted name (includes unicode support)

"Ноде Майлер" <foobar@blurdybloop.com>

To, Cc and Bcc fields accept comma separated list of e-mails or an array of emails or an array of comma separated list of e-mails - use it as you like. Formatting can be mixed.

to: 'foobar@blurdybloop.com, "Ноде Майлер" <bar@blurdybloop.com>, "Name, User" <baz@blurdybloop.com>',
cc: ['foobar@blurdybloop.com', '"Ноде Майлер" <bar@blurdybloop.com>, "Name, User" <baz@blurdybloop.com>']

You can even use unicode domain and user names, these are automatically converted to the supported form

"Unicode Domain" <info@müriaad-polüteism.info>

SMTP envelope

SMTP envelope is usually auto generated from from, to, cc and bcc fields but if for some reason you want to specify it yourself, you can do it with envelope property.

envelope is an object with the following params: from, to, cc and bcc just like with regular mail options. You can also use the regular address format, unicode domains etc.

mailOptions = {
    from: "mailer@kreata.ee",
    to: "daemon@kreata.ee",
    envelope: {
        from: "Daemon <deamon@kreata.ee>",
        to: "mailer@kreata.ee, Mailer <mailer2@kreata.ee>"

The envelope only applies when using SMTP or sendmail, setting envelope has no effect with SES.

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 mailOptions = {
    html: "Embedded image: <img src='cid:unique@kreata.ee' />",
    attachments: [{
        filename: "image.png",
        filePath: "/path/to/file",
        cid: "unique@kreata.ee" //same cid value as in the html img src

Automatic embedding images

If you want to convert images in the HTML to embedded images automatically, you can set mail option forceEmbeddedImages to true. In this case all images in the HTML that are either using an absolute URL (http://...) or absolute file path (/path/to/file) are replaced with embedded attachments.

For example when using this code

var mailOptions = {
    forceEmbeddedImages: true
    html: 'Embedded image: <img src="http://example.com/image.png">'

The image linked is fetched and added automatically as an attachment and the url in the HTML is replaced automatically with a proper cid: string.

Return callback

Return callback gets two parameters

  • error - an error object if the message failed
  • responseStatus - an object with some information about the status on success
    • responseStatus.messageId - message ID used with the message


nodemailer.sendMail(mailOptions, function(error, responseStatus){
        console.log(responseStatus.message); // response from the server
        console.log(responseStatus.messageId); // Message-ID value used

NB! Message-ID used might not be the same that reaches recipients inbox since some providers (like SES) may change the value.

Command line usage

NB! Command line usage was removed from v0.4


Run the tests with npm in Nodemailer's directory

npm test

There aren't currently many tests for Nodemailer but there are a lot of tests in the modules that are used to generate the raw e-mail body and to use the SMTP client connection.


Nodemailer in itself is actually more like a wrapper for my other modules mailcomposer for composing the raw message stream and simplesmtp for delivering it, by providing an unified API. If there's some problems with particular parts of the message composing/sending process you should look at the appropriate module.


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