openMSX

Free plan AndroidLinuxMacWindows

What openMSX is

openMSX is a free, open-source emulator for the MSX home computer system. It aims to reproduce the system with 100% accuracy and emulates almost all MSX, MSX2, MSX2+, and turboR machines; several other systems are supported experimentally. The project lists more than 230 machine configurations and more than 110 extension hardware configurations. Its built-in graphical interface works across supported operating systems.

Users can control openMSX with Tcl scripts or a command interface over pipes or a UNIX domain socket, including from external applications. The built-in debugger provides watchpoints, breakpoints, viewers, and real-time data display. Save states and a reverse feature let users replay actions or step backward, with optional event-history recording. MIDI connectivity lets applications on Windows, Mac, and Linux connect to MIDI devices in the emulated MSX.

Downloads include Windows, macOS, Linux x86 64-bit, Android ARM, and source-code builds, though the listed release versions differ by platform. openMSX 20.0 and later requires OpenGL 2 support. Android support is listed only through openMSX 0.15.0. The default C-BIOS machine does not provide every function of a complete MSX machine, and the documentation points users to a setup guide for configuring actual machines. The project provides online documentation and manuals, plus community and issue-reporting channels.

Who it suits

openMSX suits people who want to emulate MSX computers across Windows, macOS, Linux, or Android, and users who value machine configuration options, debugging, scripting, or save and reverse functions. Its command interface and MIDI connectivity also support workflows involving external applications or MIDI devices.

What it does well

Emulates MSX, MSX2, MSX2+, and turboR systems.
Lists over 230 machine configurations and over 110 extension configurations.
Built-in GUI works across supported operating systems.
Includes a debugger, save states, and a reverse feature.
Free and open source, with source-code builds available.

What to know first

openMSX 20.0 and later requires OpenGL 2 support.
Android support is listed only through version 0.15.0.
The default C-BIOS machine lacks some functionality of a complete MSX machine.
Catapult is deprecated and no longer maintained.

Limits

The free plan is listed as free. openMSX 20.0 and later requires OpenGL 2 support; Android support is listed only through 0.15.0, and the default C-BIOS machine does not provide all functionality for a complete MSX machine.

Plans

Plan	Billed and limits	Price
openMSX	MSX emulator; downloads and source code available	Free

As openmsx.org lists them, read 9 Oct 2026. The maker's own page has the final word.

Getting started

Visit the openMSX website and consult its manuals or online documentation.
Choose a Windows, macOS, Linux x86 64-bit, Android ARM, or source-code build.
Check that your system supports OpenGL 2 if you plan to use openMSX 20.0 or later.
Use the setup guide to configure an actual MSX machine if the default C-BIOS machine does not provide the functions you need.
For questions, use the openMSX forum, Discord or IRC, or the GitHub issue tracker.

Verdict

Choose openMSX if you want a free, open-source MSX emulator with broad machine coverage, debugging tools, and save and reverse features. Look elsewhere if you need a maintained Catapult interface, or check the platform version and graphics requirement before choosing a download.

Questions

How much does openMSX cost?

The listed openMSX plan costs nothing. The pricing model is free, with no free trial.

Is openMSX open source?

Yes. It is listed as open source, and downloads include source-code builds.

Which platforms have downloads?

The download list includes Windows, macOS, Linux x86 64-bit, and Android ARM builds. Listed release versions differ by platform.

What does openMSX emulate?

It emulates almost all MSX, MSX2, MSX2+, and turboR systems, plus several other systems experimentally.

Does openMSX support Android?

Yes, Android support is listed, but only through openMSX 0.15.0.

What are the setup requirements or limitations?

openMSX 20.0 and later requires OpenGL 2 support. The default C-BIOS machine does not provide all functionality for a complete MSX machine.

Facts from openMSX's own pages

Android limit: The features page lists Android 4.1+ support only up to openMSX 0.15.0. · openmsx.org, 9 Oct 2026
Built-in GUI: It includes a graphical user interface that works the same across supported operating systems. · openmsx.org, 9 Oct 2026
Debugger: The built-in debugger includes watchpoints, breakpoints, viewers and real-time data display. · openmsx.org, 9 Oct 2026
Downloads: The download list includes Windows, macOS, Linux x86 64-bit, Android ARM and source code builds; listed release versions differ by platform. · openmsx.org, 9 Oct 2026
Emulated systems: It emulates almost all MSX systems, including MSX, MSX2, MSX2+, and turboR generations. · openmsx.org, 9 Oct 2026
External integrations: The command interface can connect openMSX to external applications, and MIDI connectivity is available through host frameworks on Windows, Mac, and Linux. · openmsx.org, 9 Oct 2026
Graphical interface: It includes a built-in graphical user interface that works the same across supported operating systems. · openmsx.org, 9 Oct 2026
Graphics requirement: The project says openMSX 20.0 and later requires a system with OpenGL 2 support. · openmsx.org, 9 Oct 2026
GUI status: Catapult is deprecated and no longer maintained; the documentation recommends the built-in GUI in openMSX 20.0 and later. · openmsx.org, 9 Oct 2026
Hardware emulation: It emulates almost all MSX, MSX2, MSX2+ and turboR systems, plus several other systems on an experimental basis. · openmsx.org, 9 Oct 2026
Hardware library: The feature page lists over 230 machine configurations and over 110 extension hardware configurations. · openmsx.org, 9 Oct 2026
Host connectivity: MIDI connectivity lets applications on Windows, Mac and Linux connect to MIDI devices in the emulated MSX. · openmsx.org, 9 Oct 2026
Legacy GUI: Catapult is no longer maintained; the project encourages using the built-in GUI in openMSX 20.0 and later. · openmsx.org, 9 Oct 2026
Machine configurations: The project says it includes over 230 MSX and similar machine configurations and over 110 extension hardware configurations. · openmsx.org, 9 Oct 2026
Platforms: The feature page lists Linux, Windows 7 or later, macOS, and Android 4.1 or later through openMSX 0.15.0; current downloads include Windows, macOS, Linux, and an older Android APK. · openmsx.org, 9 Oct 2026
Purpose: openMSX is an emulator for the MSX home computer system that aims to emulate it with 100% accuracy. · openmsx.org, 9 Oct 2026
Reverse and save states: It supports save states and a reverse feature for replaying actions or stepping back in time, with optional event-history recording. · openmsx.org, 9 Oct 2026
Save and rewind: It supports cross-platform save states and a reverse feature for replaying actions or stepping back through time. · openmsx.org, 9 Oct 2026
Scripting and control: Tcl scripts and a command interface over pipes or a UNIX domain socket let users and external applications control openMSX. · openmsx.org, 9 Oct 2026
Security and compliance: The official site does not provide security or compliance claims on the pages reviewed. · openmsx.org, 9 Oct 2026
Setup limitation: The documentation says the default C-BIOS machine does not provide all functionality for a complete MSX machine and points users to a setup guide for configuring actual MSX machines. · openmsx.org, 9 Oct 2026
Support: Users can ask questions in the Discord channel or IRC, use the openMSX forum, or file bugs and feature requests in GitHub’s issue tracker. · openmsx.org, 9 Oct 2026
Support and documentation: The project provides online manuals and documentation, and links to an MSX forum and its contact page. · openmsx.org, 9 Oct 2026
Technical requirement: The site says openMSX 20.0 and later requires a system with OpenGL 2 support. · openmsx.org, 9 Oct 2026

Where openMSX stands on Freedom251

Multi-System Emulators#31 of 54