ActionMailerPixel allows you to easily track your mailers' open rate.

When you enable the open tracking pixel on a mailer, a simple img tag will be inserted right before the closing body tag upon delivery. The source of the image tag leads to the /open.png path wherever you mounted the engine in your application. The response is a 1x1px transparent PNG image. When the email is opened by an email client, the pixel might get rendered (depending on the security/privacy settings) and the opening will be saved. Open rate is tracked by user and by email campaign. This way you can see exactly who opened a specific email.

1. Default (convention over configuration) - pixel is created with the first available of the following:

• @user -> params[:user] -> recipient_class.find_by(email: message.to.first)
• @campaign -> params[:campaign]

class PixelMailer < ApplicationMailer
  open_tracking_pixel

  def sample
    mail(to: '[email protected]')
  end
end

2. Explicit use - pixel is created with the provided data

class PixelMailer < ApplicationMailer
  open_tracking_pixel recipient: -> { params[:user] },
                      campaign:  -> { params[:campaign] }

  def sample
    mail(to: '[email protected]')
  end
end

Add this line to your application's Gemfile:

gem 'action_mailer_pixel'

And then execute:

$ bundle
$ bundle exec rails action_mailer_pixel:install:migrations
$ bundle exec rails db:migrate
$ bundle exec rails action_mailer_pixel:install

Mount the engine on a path of choice in config/routes.rb:

mount ActionMailerPixel::Engine => '/action_mailer_pixel'

Contributions are welcome.

The gem is available as open source under the terms of the MIT License.