Guerrilla SMTPd is minimalist, event-driven I/O, non-blocking SMTP server. The design goal and purpose of Guerrilla SMTPd is to receive large volumes of email and nothing much else. It happily gobbles down millions of emails every week on a single processor system.

WasteMail SMTPd is a SMTP mail daemon written in Erlang. It is roughly inspired by Guerrilla SMTPd and shares the goal of receiving large amounts of e-mail and eating up spam. However, its target database system is CouchDB and with Erlang/OTP at its backend it is predestinated for multi-core systems and even large clustering environments and should be able to sustain very high loads. WasteMail SMTPd will be the magic behind wastemail.org, yet another temporary e-mail address service.