Postal is a complete and fully featured mail server for use by websites & web servers. Think Sendgrid, Mailgun or Postmark but open source and ready for you to run on your own servers. Postal was developed by aTech Media to serve its own mail processing requirements and we have since decided that it should be released as an open source project for the community. It was originally launched by us as AppMail but renamed to Postal as part of making it open source as we felt the name was more suitable.
The application has been running in production for us for nearly 6 months and we will be continuing to use it ourselves and support its ongoing development. We are still just putting a few finishing touches to the documentation & installation instructions but we'll make it as easy as possible. If you have any questions about getting up and running, just post an issue.