hMailServer was a free email server for Windows created by Martin Knafve.

It ran as a Windows service and includes administration tools for management and backup.

The actual email messages were stored on disk in a raw MIME format.

As of January 15th, 2022, active support and development were officially halted,[2] although version 5.6 will continue to receive updates for critical bugs.

Common features such as multiple-domain support, aliases, catch-all and basic mailing lists were present.