PythonAPI for Sendmail Milters. Related modules provide features such as content filtering, SPF, and reputation tracking. Changes are posted first to https://github.com/sdgathman/pymilter and related repos.
elspy is an extension to the Exim MTA that allows Exim users to supply a local_scan() function written in Python instead of C. (Exim's local_scan() API lets sysadmins supply site-specific code for approving/rejecting email messages at SMTP time.)
Virtual Qmail - virtual domains management system for qmail. It is designed to be fast, reliable, and easy to use. Includes software allowing users to manage their accounts via WWW.