gen_smtp
https://github.com/Vagabond/gen_smtp
A generic Erlang SMTP client and server framework that can be extended via callback modules in the OTP style.
Since release 0.7, gen_smtp is in use by Zotonic for all e-mail handling in Zotonic, both outgoing and incoming. gen_smtp is maintained by Andrew Thompson.
Before 0.7 we used esmtp Is used by the module mod_emailer for all the e-mail handling in Zotonic. esmtp Is maintained by Geoff Cant.