openMSX

openMSX is an MSX emulator whose goal is to emulate every part of the MSX system perfectly. It covers MSX1, MSX2, MSX2+ and turbo R computers, with configurations for hundreds of real machines, and a long list of extensions such as sound cartridges, disk drives, hard disk interfaces and the Pioneer Palcom LaserDisc player.

It includes C-BIOS, a free replacement for the MSX system ROMs, so cartridge games can be played without dumping a real machine. Since version 20.0 openMSX has had a graphical interface built in, with a powerful debugger, and version 21.0 added setups, which save a complete machine with its drives and controllers so it can be loaded again in one step. It also has save states, a rewind feature, video recording and a Tcl scripting console.

openMSX is actively developed, and version 21.0 was released in September 2025. Official builds are available for Windows, macOS on Intel and Apple Silicon, and Linux. It is released under the GNU GPL.