Rails includes a way to see what an e-mail will look like.

Integration to RSpec

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All you need to do is implement a preview-class in spec/mailers/previews/notifier_preview.rb:

class NotifierPreview < ActionMailer::Preview
  def welcome
    Notifier.welcome(User.first)
  end
end

And adapt the preview load path in your application.rb:

config.action_mailer.preview_path = "#{Rails.root}/spec/mailers/previews" # this is already set as default by Rails

Then a preview will be available in the browser at http://localhost:3000/rails/mailers/notifier/welcome as well as a list of previews at http://localhost:3000/rails/mailers.

Rails <4.1

You could use Mailcatcher.

See also

• You can preview mails directly in your client
• You might want to add specs for your mailer preview too