Build Robust & Production Quality Applications - Lesson 6: Mailgun & Heroku

To send emails from your Heroku app using Mailgun is simple:

1. Mailgun Addon

Add the Mailgun add-on to your Heroku app through the command line (within your app project directory)

heroku addons:create mailgun

or you can add via their web interface

2. Change your smtp settings

Then you copy and paste their smtp settings into your config/production.rb file. Make sure to change your domain name and add your default url options (which should point to your domain name) - if not, you will get an error: Errno::ECONNREFUSED: Connection refused - connect(2) for action mailer ...port(25)

config.action_mailer.delivery_method = :smtp
  # SMTP settings for mailgun
  config.action_mailer.smtp_settings = {
    :port           => ENV['MAILGUN_SMTP_PORT'],
    :address        => ENV['MAILGUN_SMTP_SERVER'],
    :user_name      => ENV['MAILGUN_SMTP_LOGIN'],
    :password       => ENV['MAILGUN_SMTP_PASSWORD'],
    :domain         => 'aqueous-coast-5067.herokuapp.com',
    :authentication => :plain,
  }
  config.action_mailer.default_url_options = { :host => 'aqueous-coast-5067.herokuapp.com' }

3. Heroku config

You do not have to store the ENV variable in application.yml, you only have to run "heroku config" from your command line.

4. If you find you do need to store ENV variable in your app, check out Figaro.