Mail::Spool is a "pure perl" implementation of mail spooling, unspooling and sending. It is intended to be used with daemons such as Net::Server::SMTP (to be released soon), but it also contains its own daemon (based off of Net::Server::Fork) that can be used if necessary. It is also intended to be used as a quick spooling mechanism for perl scripts. As it can write straight to the queue without opening another process. WWW: https://metacpan.org/release/Mail-Spool