c64js
c64js: A free browser emulator for quick PRG demos, with partial graphics support. Ranked #28 of 31 in Commodore 64 Emulators by our editors (5.8/10); pricing: Free plan; best for quick browser-based PRG demos.
At a glance
- Editor score5.8 / 10
- PricingFree plan
- Best forQuick browser-based PRG demos
- Free planYes
- Paid fromFree
- Supported platformsweb
- Facts checked21 Sep 2026
Where it wins
- Runs in a web browser with a canvas-based interface
- Loads .prg files by dropping them onto the emulator canvas
- Open-source project built with vanilla JavaScript and MIT licensing
Where it doesn't
- VIC-II graphics emulation is incomplete
- SID sound is not emulated
- Only a limited number of ROMs work correctly
Our verdict on c64js
c64js is a free, open-source Commodore 64 emulator delivered as a browser demo. It is aimed at people who want to inspect or demonstrate compatible .prg-format ROM files directly on the web, without installing a desktop emulator. The interface uses a canvas, and files can be loaded by dropping them onto that canvas. Its implementation is written from scratch in vanilla JavaScript, making it a focused fit for browser-based PRG demonstrations rather than a full replacement for a complete Commodore 64 environment.
The web-first design keeps the interaction straightforward: open the browser interface, then drop a supported .prg file onto the emulator canvas. The published project also includes npm and Gulp instructions for building a production distribution, which gives developers a defined path for working with the source. Its platform scope is narrow, however, with web listed as the supported platform and .prg as the supported disk or tape format.
The main technical boundary is emulation depth. c64js includes partial VIC-II graphics emulation, but the VIC-II implementation is incomplete, SID sound is not emulated, and only a limited number of ROMs are expected to work correctly. That makes it suitable for quick visual demos and lightweight experimentation with compatible PRG files. Users who need broader software compatibility, complete graphics behavior, sound emulation, or wider media-format support should choose a more complete Commodore 64 emulator instead.
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c64js pricing
c64js fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Free |
| Supported platforms | web |
| Disk and tape formats | .prg |
| Built-in debugger | Not verified |
| Netplay support | Not verified |
| Emulated C64 variants | Not verified |
| Bundled software library | Not verified |
| Deployment | Cloud |
| Platforms | Web |
| Built for | Solo, Small business (editorial estimate) |
| Pricing | Free plan |
| Website | github.com |
| Facts checked | 21 Sep 2026 |
Alternatives to c64js
- VICEFree, open-source C64 emulation with cycle accuracy, debugging, media support and network play.9.4
- Breadbin466A free, open-source C64 emulator built for accurate hardware behavior and debugging.9.0
- C64 ForeverA Windows-focused C64 package with bundled titles, broad emulation, and preservation tools.8.8
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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