Miracle

Spec sheet

Purpose

Miracle is a JavaScript Sega Master System emulator that runs in a browser.Read 7 Oct 2026 · miracle.xania.org

Product

Miracle is a JavaScript Sega Master System emulator that runs inside a browser.Read 7 Oct 2026 · miracle.xania.org

License

The maker describes Miracle as free software under the GNU General Public License, version 3 or later.Read 7 Oct 2026 · miracle.xania.org

Maker

The page credits Matt Godbolt as the maker.Read 7 Oct 2026 · miracle.xania.org

Build requirement

The project README says building requires Node.js version 18 or later.Read 7 Oct 2026 · github.com

Controls

The cursor keys and Z/Y and X control the emulator; P pauses it and R resets it.Read 7 Oct 2026 · miracle.xania.org

CPU test suite

The project README reports 1,329 of 1,356 FUSE Z80 CPU tests passing and says the 27 skipped tests cover behaviors not relevant to SMS emulation.Read 7 Oct 2026 · github.com

Credits

Miracle is based on JSSpeccy by Matt Westcott, which in turn is based on Fuse by Philip Kendall and others.Read 7 Oct 2026 · miracle.xania.org

Debugger

The emulator includes a built-in debugger that opens with Backspace.Read 7 Oct 2026 · miracle.xania.org

Debugger controls

The interface includes play, pause, step, step over, step out, reset, and open ROM controls.Read 7 Oct 2026 · miracle.xania.org

Emulation tests

The repository says 1,329 of 1,356 FUSE Z80 CPU tests pass and identifies 27 skipped tests as covering undocumented behavior not relevant to SMS emulation.Read 7 Oct 2026 · github.com

Emulator controls

The interface provides Play, Pause, Step, Step Over, Step Out, and Reset controls.Read 7 Oct 2026 · miracle.xania.org

Platform

The product is described as running totally inside a browser.Read 7 Oct 2026 · miracle.xania.org

Project lineage

Miracle is based on JSSpeccy, which in turn is based on Fuse.Read 7 Oct 2026 · miracle.xania.org

ROM loading

Users can open a ROM file in the browser or select a listed game.Read 7 Oct 2026 · miracle.xania.org

ROMs

The page lets users open a ROM file or select a listed game.Read 7 Oct 2026 · miracle.xania.org

Source code

The public repository says Miracle can be tried at miracle.xania.org and documents building it with Node.js v18 or later.Read 7 Oct 2026 · github.com

Warranty

The maker states that the program is provided without warranty, including implied warranties of merchantability or fitness for a particular purpose.Read 7 Oct 2026 · miracle.xania.org

Where Specifiction places it

• Sega Master System Emulators#20 of 256.7