MIX is a high-performance, indexed, on-disk email storage system that is designed for use with the
IMAP protocol. MIX was designed by
Mark Crispin, the author of the IMAP protocol. Server support for it has been included in releases of
UW IMAP since 2006, Panda IMAP, and
Messaging Architects Netmail. MIX is also supported directly by the
Alpine e-mail client.