EmulatorJS
EmulatorJS is a free, open-source web frontend for RetroArch that lets site owners embed an emulator into a website.
What EmulatorJS is
EmulatorJS is a free, open-source web frontend for RetroArch that lets site owners embed an emulator into a website. A code generator creates embed code, which the project says can be added with a few lines. It uses RetroArch’s libretro cores to emulate games, with documented systems including NES, Nintendo 64, PlayStation, PSP, Sega systems, and Commodore systems; the project warns that its list may be out of date. Built-in customization and multiple language options are available. EmulatorJS is a library or plugin rather than a standalone website, and it does not provide a Docker container. A public CDN offers version paths labeled stable, latest, and nightly. The project lists web, Android, iOS, and self-hosted platforms. Pages using EmulatorJS must be served through a web server; opening an HTML file directly is unsupported. Threaded cores may improve performance, but they require SharedArrayBuffer enabled through COOP and COEP response headers. The changelog labels version 4.3.0-pre as a prerelease and advises against using it where production stability is needed.
Good
- Code generator helps create embed code.
- Uses RetroArch libretro cores.
- Includes built-in customization and multiple languages.
- Public CDN offers stable, latest, and nightly paths.
- Free and open source.
Watch out
- Opening the HTML file directly is unsupported.
- No Docker container is provided.
- Threaded cores require COOP and COEP headers.
- The documented supported-systems list may be out of date.
Who it suits
EmulatorJS suits site owners who want to embed a RetroArch-based emulator and customize it for supported systems. Users should be comfortable serving a web page and configuring response headers if they want threaded cores.
Verdict
EmulatorJS is an embeddable emulator frontend, not a standalone website or containerized service. Check the system list and hosting requirements before using it, especially for threaded cores.
Plans and prices
From EmulatorJS's own pricing page, checked 8 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Free | Free | Free and ad-free project |
The facts
Each one read from EmulatorJS's own pages, with the date it was checked.
Where it runs
- Browser requirement
- The FAQ says users must serve the page through a web server; opening the HTML file directly is unsupported.checked 8 Oct 2026
What it does
- CDN
- The project provides a public CDN with version paths including stable, latest, and nightly.checked 8 Oct 2026
- Code generator
- The site provides a code generator for creating embeddable EmulatorJS code.checked 8 Oct 2026
- Customization
- The project provides built-in customization options and supports multiple languages.checked 8 Oct 2026
- Embedding
- A few lines of code can embed the emulator into a website.checked 8 Oct 2026
- Emulation cores
- EmulatorJS uses RetroArch's libretro cores to emulate games.checked 8 Oct 2026
- Integrations
- The project describes itself as a library or plugin rather than a standalone website and says it does not provide a Docker container.checked 8 Oct 2026
- Open source
- The official site describes EmulatorJS as open source.checked 8 Oct 2026
- Performance option
- Threaded cores may improve performance, but require SharedArrayBuffer enabled through COOP and COEP response headers.checked 8 Oct 2026
- Purpose
- EmulatorJS is a web-based frontend for RetroArch that lets users embed an emulator in a website.checked 8 Oct 2026
- Release stability
- The changelog labels version 4.3.0-pre as a prerelease and advises against using it where production stability is needed.checked 8 Oct 2026
- Support
- The project directs users to report issues on GitHub and include browser console logs and the version they use.checked 8 Oct 2026
- Supported systems
- The supported systems documentation lists platforms including NES, Nintendo 64, PlayStation, PSP, Sega systems, and Commodore systems, and notes that its list may be out of date.checked 8 Oct 2026
The company
- Maker
- The site credits @ethanaobrien and @allancoding.checked 8 Oct 2026
Alternatives to EmulatorJS
- 1
ES-DE Frontend
Free planOpen sourceAndroidLinuxmacOSWindows8.3$6.50 one-time - 2
GameEx
Free planAndroidLinuxmacOSWindows7.8$17 one-time - 3
LaunchBox
Free planAndroidAPIWindows7.8$30 one-time - 4
RetroArch
Free planAndroidiOSWebLinux7.7Free plan - 5
Attract-Mode
Free planOpen sourceAPILinuxmacOSSelf-hosted7.5Free plan - 6
Lakka
Free planLinuxmacOSSelf-hostedWindows6.8Free plan