[2] Originally written in 1997 by Wietse Venema at the IBM Thomas J. Watson Research Center in New York, and first released in December 1998,[3] Postfix continues as of 2024[update] to be actively developed by its creator and other contributors.

Administrators can combine Postfix with other software that provides spam/virus filtering (e.g., Amavisd-new), message-store access (e.g., Dovecot), or complex SMTP-level access-policies (e.g., postfwd, milter-regex, policyd-weight).

The Postfix core consists of several dozen server programs that run in the background, each handling one specific aspect of email delivery.

For damage-control purposes, most server programs run with fixed reduced privileges, and terminate voluntarily after processing a limited number of requests.

Other programs provide administrative support to start or stop Postfix, query status information, manipulate the queue, or to examine or update its configuration files.

For example, the "vstring" primitive makes Postfix code resistant to buffer overflow[7] attacks, and the "safe open" primitive makes Postfix code resistant to race condition attacks on systems that implement the POSIX file system API.

This approach makes Postfix highly resilient, as long as the operating system or hardware don't fail catastrophically.

One single Postfix instance has been clocked at ~300 message deliveries/second[8] across the Internet, running on commodity hardware (a vintage-2003 Dell 1850 system with battery-backed MegaRAID controller and two SCSI disks).

This delivery rate is an order of magnitude below the "intrinsic" limit of 2500 message deliveries/second[8] that was achieved with the mail queue on a RAM disk while delivering to the "discard" transport (with a dual-core Opteron system in 2007).