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2.6.0 • Public • Published

SMTP transport module for Nodemailer

Build Status NPM version

Applies for Nodemailer v1.x and not for v0.x where transports are built-in.


Install with npm

npm install nodemailer-smtp-transport

Require to your script

var nodemailer = require('nodemailer');
var smtpTransport = require('nodemailer-smtp-transport');


Create a Nodemailer transport object

var transporter = nodemailer.createTransport(smtpTransport(options))

or (by using smtpTransport as default)

var transporter = nodemailer.createTransport(options)


  • options defines connection data
    • options.port is the port to connect to (defaults to 25 or 465)
    • is the hostname or IP address to connect to (defaults to 'localhost')
    • defines if the connection should use SSL (if true) or not (if false)
    • options.auth defines authentication data (see authentication section below)
    • options.ignoreTLS turns off STARTTLS support if true
    • optional hostname of the client, used for identifying to the server
    • options.localAddress is the local interface to bind to for network connections
    • options.connectionTimeout how many milliseconds to wait for the connection to establish
    • options.greetingTimeout how many milliseconds to wait for the greeting after connection is established
    • options.socketTimeout how many milliseconds of inactivity to allow
    • options.logger optional bunyan compatible logger instance. If set to true then logs to console. If value is not set or is false then nothing is logged
    • options.debug if set to true, then logs SMTP traffic, otherwise logs only transaction events
    • options.authMethod defines preferred authentication method, eg. 'PLAIN'
    • options.tls defines additional options to be passed to the socket constructor, eg. {rejectUnauthorized: true}
    • getSocket optional method that is called every time a new connection is made against the SMTP server. This method can provide an existing socket to be used instead of creating a new one

Alternatively you can use connection url with protocol 'smtp:' or 'smtps:'. Use query arguments for additional configuration values.


var transporter = nodemailer.createTransport(smtpTransport({
    host: 'localhost',
    port: 25,
    auth: {
        user: 'username',
        pass: 'password'

Or with connection url (gmail)

var transporter = nodemailer.createTransport(


If authentication data is not present, the connection is considered authenticated from the start.

Set authentcation data with options.auth


  • auth is the authentication object
    • auth.user is the username
    • auth.pass is the password for the user
    • auth.xoauth2 is the OAuth2 access token (preferred if both pass and xoauth2 values are set) or an XOAuth2 token generator object.

If a XOAuth2 token generator is used as the value for auth.xoauth2 then you do not need to set the value for auth.user. XOAuth2 generator generates required accessToken itself if it is missing or expired. In this case if the authentication fails, a new token is requested and the authentication is retried once. If it still fails, an error is returned.

Install xoauth2 module to use XOauth2 token generators (not included by default)

npm install xoauth2 --save

XOAuth2 Example

NB! The correct OAuth2 scope for Gmail is

var nodemailer = require('nodemailer');
var generator = require('xoauth2').createXOAuth2Generator({
    user: '{username}',
    clientId: '{Client ID}',
    clientSecret: '{Client Secret}',
    refreshToken: '{refresh-token}',
    accessToken: '{cached access token}' // optional
// listen for token updates
// you probably want to store these to a db
generator.on('token', function(token){
    console.log('New token for %s: %s', token.user, token.accessToken);
// login
var transporter = nodemailer.createTransport(({
    service: 'gmail',
    auth: {
        xoauth2: generator
// send mail
    from: '',
    to: '',
    subject: 'hello world!',
    text: 'Authenticated with OAuth2'
}, function(error, response) {
   if (error) {
   } else {
        console.log('Message sent');

Using well-known services

If you do not want to specify the hostname, port and security settings for a well known service, you can use it by its name (case insensitive)

    service: 'gmail',
    auth: ..

See the list of all supported services here.

Verify connection configuration

You can verify your configuration with verify(callback) call. If it returns an error, then something is not correct, otherwise the server is ready to accept messages.

// verify connection configuration
transporter.verify(function(error, success) {
   if (error) {
   } else {
        console.log('Server is ready to take our messages');




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