Is there an open source email similar to mailchimp

Question

there is an open source server (preferably in Ruby on Rails, so I can configure it) that serves something like MailChimp or SendGrid. I basically want it to handle things like retries and unsubscribing.

Answer 1

See this SO question for a list of php applications in this space.

The "problem" of sending personalized newsletters by e-mail has been with us for more than ten years. As a result, second-generation open source solutions were written in the "back-most use perl" or "php" mode, since then they were suitable languages.

You asked about Rails solutions: I would be careful to use a relatively new Rails application for this problem space. Instead, I recommend that you create a Ruby API for one of the classic mailing applications and then use it. By doing so, you will have the advantage of a feature-rich, well-tested application to use.