spampd binary package in Ubuntu Bionic amd64

 spampd is an SMTP/LMTP server designed to be hooked into the
 MTA processing chain (e.g. as a content filter). It is
 written in Perl and uses the Net::Server framework. It is
 intended to provide spam filtering at the system level (i.e.
 ususally for all users). If you rely on per-user configuration
 or per-user Bayes databases, spampd is not for you.
 .
 The major advantage of spampd over plain SpamAssassin (both
 directly and through spamd) is that it doesn't need to load
 all needed perl modules on every invocation or spawn
 a C programme for every mail it receives. Compared to using
 spamc/spamd, spampd can usually provide a 25% performance
 increase with local-only tests.
 .
 The advantage of spampd over amavisd-new is that it uses the
 original SpamAssassin header tags, which are more verbose than
 the tags which amavisd-new provides. This allows easier
 filtering in the mail client and easier tuning of SpamAssassin.

Source package