Preview Emails in Rails

As of Rails 4.1, you can now preview emails while developing (without sending an email). Let's say you have a mailer that looks like this:

app/mailers/notification_mailer.rb

class NotificationMailer < ActionMailer::Base

  def welcome(user)
    @user = user
    mail :to => user.email, :from => 'me@mydomain.com',
      :subject => 'Welcome!'
  end

end

To preview it, create a file in test/previews and call the mailer method just as you would from any model or controller in your app.

test/previews/notification_preview.rb

class NotificationPreview < ActionMailer::Preview

  def welcome
    NotificationMailer.welcome(User.first)
  end

end

Then you can preview the email at [/rails/mailers/notification/welcome](http:// rails/mailers/notification/welcome).

Notice the preview route matches the preview class name and then preview method, which doesn't necessarily need to be related to the mailer itself.

Also note the preview filename is appended with _preview.