SMTP Server and Web Interface for reading and testing emails during development


MailDev is a simple way to test your project's generated emails during development with an easy to use web interface that runs on your machine built on top of Node.js.

$ npm install -g maildev
$ maildev

If you want to use MailDev with Docker, you can use this image on Docker Hub.

maildev [options]

  -h, --help              output usage information
  -V, --version           output the version number
  -s, --smtp [port]       SMTP port to catch emails [1025]
  -w, --web [port]        Port to run the Web GUI [1080]
  --outgoing-host <host>  SMTP host for outgoing emails
  --outgoing-port <port>  SMTP port for outgoing emails
  --outgoing-user <user>  SMTP user for outgoing emails
  --outgoing-pass <pass>  SMTP password for outgoing emails
  --outgoing-secure       Use SMTP SSL for outgoing emails
  -o, --open              Open the Web GUI after startup
  -v, --verbose

MailDev can be used in your Node.js application. For more info view the API docs.

var MailDev = require('maildev');
var maildev = new MailDev();
maildev.on('new', function(email){
  // We got a new email! 

MailDev also has a REST API. For more info view the docs.

Maildev optionally supports selectively relaying email to an outgoing SMTP server. If you configure outgoing email with the --outgoing-xxx options you can click "Relay" on an individual email to relay through MailDev out to a real SMTP service that will really send the email.


$ maildev --outgoing-host --outgoing-secure --outgoing-user '' --outgoing-pass '<pass>'

Configure your application to send emails via port 1025 and open localhost:1080 in your browser.

Nodemailer (v1.0+)

var transport = nodemailer.createTransport({
  port: 1025,
  ignoreTLS: true,
  // other settings... 

Nodemailer (v0.7)

var transport = nodemailer.createTransport("SMTP", {
  port: 1025,
  // other settings... 

Django -- Add EMAIL_PORT = 1025 in your settings file [source]

Rails -- config settings:

config.action_mailer.delivery_method = :smtp
    config.action_mailer.smtp_settings = { 
        :address => "localhost",
        :port => 1025
  • Toggle between HTML, plain text views as well as view email headers
  • Test Responsive Emails w/ resizeable preview pane available for 320/480/600px screen sizes
  • Ability to receive and view email attachments
  • Websockets keep the interface in sync once emails are received
  • Command line interface for configuring SMTP and Web interface ports
  • Ability to relay email to an upstream SMTP server

If you're using MailDev and you have a great idea, I'd love to hear it. If you're not using MailDev because it lacks a feature, I'd love to hear that too. Add an issue to the repo here or contact me on twitter.

Any help on MailDev would be awesome. There is plenty of room for improvement. Feel free to create a Pull Request from small to big changes.

To run MailDev during development:

# grunt-cli is needed by grunt; ignore this if already installed
npm install -g grunt-cli
npm install
grunt dev

The grunt dev task will run the project using nodemon and restart automatically when changes are detected. SASS files will be compiled automatically on save also. To trigger some emails for testing run node test/send.js in a separate shell. Please run jshint to your lint code before submitting a pull request; run grunt jshint.

To run the test suite, use Mocha:

$ npm install -g mocha
$ mocha

0.9.0 - Add ability to download .eml files

0.8.1 - Fix temp directory bug introduced in 0.8.0

0.8.0 - Add view email source. Fix running multiple instances.

0.7.0 - Add Docker support

0.6.3 - Add auto-show new email. UI adjustments.

0.6.2 - Fix module entry point. Bug fixes.

0.6.1 - Bug fixes and improvements

0.6.0 - Add relay option to send outgoing emails. Refactor for new API.

0.5.2 - Lock down dependency versions

0.5.1 - Fix menu layout issue in Safari

0.5.0 - Add command line interface. Web UI redesign.

0.4.0 - Add ability to receive and view attachments

0.3.1 - Add for immediate email arrival to interface

0.3.0 - Initial open source release

MailDev is built on using great open source projects including Express, AngularJS, Font Awesome and two great projects from Andris Reinman: Simple SMTP and Mailparser. Many thanks to Andris as his projects are the backbone of this app and to MailCatcher for the inspiration.

Additionally, thanks to all the awesome contributors to the project.