JSMoo
The facts below are what the maker publishes about JSMoo, checked and dated. Our editors have not written about it yet.
Plans and prices
From JSMoo's own pricing page, checked 11 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| JSMoo | Free | MIT-licensed open-source emulator |
The facts
Each one read from JSMoo's own pages, with the date it was checked.
Where it runs
- BIOS requirement
- Sega Master System and ZX Spectrum require BIOS files, which can be uploaded under Settings/BIOS.checked 11 Oct 2026
- Browser use
- JSMoo runs in a browser and the README recommends Chrome for speed.checked 11 Oct 2026
What it does
- Known limitation
- The README says ZX Spectrum keyboard input was temporarily broken at the time of that commit.checked 11 Oct 2026
- Learning focus
- The maker says the project aims to make vintage systems and processors easier for people to play and understand, including through planned Easy6502-like learning pages.checked 11 Oct 2026
- License
- The repository says JSMoo is distributed under the MIT License.checked 11 Oct 2026
- Local setup
- The README instructs users to clone the repository, run its Python 3 server script, and open the local address in Chrome.checked 11 Oct 2026
- Purpose
- JSMoo is an attempt to make accurate, performant retro-system emulators in JavaScript and AssemblyScript.checked 11 Oct 2026
- ROM and controls
- Users can upload ROM files and remap controls in the Settings tab.checked 11 Oct 2026
- SNES emulation
- The README describes cycle-accurate 65816 emulation, not-quite-cycle-accurate SPC700 emulation, scanline-based PPU rendering, and no DSP emulation in its proof of concept.checked 11 Oct 2026
- Support and contributions
- The maker invites bug fixes, optimizations, cleanup, and other improvements through GitHub forks and pull requests.checked 11 Oct 2026
- Supported systems
- The project describes current support for SNES, NES, Game Boy, Sega Master System, ZX Spectrum, and Game Gear.checked 11 Oct 2026
- Technical requirements
- The project uses SharedArrayBuffers and high-precision timers, so it requires special HTTP headers and cannot be run by opening index.html directly from disk.checked 11 Oct 2026
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