The PostBox Service is used to send emails from your ColdBox applications, as a direct replacement to the stock ColdBox MailService Plugin. Emails are sent through PostMarkApp.com API rather than over standard SMTP.

PostMarkApp (http://postmarkapp.com/) is a web service based email provider. Rather than sending emails using standard SMTP protocols, you make a REST request to their API. Each mail is then assigned a message_id, you can then use their bounce back API's and webhooks to track mail delivery.

Simply replace references to the standard MailService in your application so they point at the PostBox plugin rather than the stock MailService plugin. You also need to add a custom setting to your ColdBox configuration file which contains your PostMarkApp API key.

e.g. 

// custom settings

     settings = {

          // PostMarkApp Settings

          PostMarkApiKey = "your-api-key-goes-here"

     };

Once this plugin is in place, you'll be able to use it to build and send emails in the same way as the stock ColdBox mail service plugin.