Miracle

What Miracle is

Miracle is free JavaScript software that emulates the Sega Master System entirely in a web browser. Users can open a ROM file or select a listed game without leaving the browser. The interface provides Play, Pause, Step, Step Over, Step Out, Reset, and ROM-opening controls. Keyboard input uses the cursor keys, Z/Y, and X; P pauses the emulator and R resets it. Pressing Backspace opens a built-in debugger. Miracle is credited to Matt Godbolt and builds on JSSpeccy by Matt Westcott, which in turn is based on Fuse by Philip Kendall and others. The project’s source code is publicly available, and its README says building requires Node.js version 18 or later. That README reports 1,329 of 1,356 FUSE Z80 CPU tests passing; 27 skipped tests concern undocumented behavior described as not relevant to SMS emulation. Miracle is offered under the GNU General Public License, version 3 or later, without warranty, including implied warranties of merchantability or fitness for a particular purpose.