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EmulatorJS
What it is
EmulatorJS is an open-source frontend for RetroArch that lets users embed an emulator in a website. A code generator helps create the embed, which the project says can be added with a few lines of code. It uses RetroArch’s libretro cores, with documented systems including NES, Nintendo 64, PlayStation, PSP, Sega systems, and Commodore systems; the project cautions that this list may be out of date.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 stable, latest, and nightly version paths. The page containing the embed must be served through a web server; opening an HTML file directly is unsupported. Threaded cores may improve performance, but require SharedArrayBuffer enabled using COOP and COEP response headers. EmulatorJS is free and lists web, Android, iOS, and self-hosted platforms. Its changelog labels version 4.3.0-pre as a prerelease and advises against using it when production stability is needed. For issue reports, the project asks users to include browser console logs and the version in use.
For and against
For
- Code generator helps create website embeds.
- Uses RetroArch libretro cores.
- Customization options and multiple languages are available.
- Public CDN has stable, latest, and nightly paths.
Against
- Opening the HTML file directly is unsupported.
- Threaded cores require COOP and COEP headers.
- Version 4.3.0-pre is a prerelease.
The verdict
EmulatorJS provides an embeddable, open-source route to libretro emulation, with customization and a code generator. Account for its web-server requirement and the stated limits around threaded cores and prerelease stability.
Who it suits
EmulatorJS suits people who want to add an emulator to a website and can serve the page through a web server. Its listed platforms also include Android, iOS, and self-hosted use.
Plans and prices
Free
Free and ad-free project
Read 8 Oct 2026 · github.com
On the record
- Browser requirement
- The FAQ says users must serve the page through a web server; opening the HTML file directly is unsupported.emulatorjs.org · read 8 Oct 2026
- CDN
- The project provides a public CDN with version paths including stable, latest, and nightly.emulatorjs.org · read 8 Oct 2026
- Code generator
- The site provides a code generator for creating embeddable EmulatorJS code.emulatorjs.org · read 8 Oct 2026
- Customization
- The project provides built-in customization options and supports multiple languages.emulatorjs.org · read 8 Oct 2026
- Embedding
- A few lines of code can embed the emulator into a website.emulatorjs.org · read 8 Oct 2026
- Emulation cores
- EmulatorJS uses RetroArch's libretro cores to emulate games.emulatorjs.org · read 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.github.com · read 8 Oct 2026
- Maker
- The site credits @ethanaobrien and @allancoding.emulatorjs.org · read 8 Oct 2026
- Open source
- The official site describes EmulatorJS as open source.emulatorjs.org · read 8 Oct 2026
- Performance option
- Threaded cores may improve performance, but require SharedArrayBuffer enabled through COOP and COEP response headers.emulatorjs.org · read 8 Oct 2026
- Purpose
- EmulatorJS is a web-based frontend for RetroArch that lets users embed an emulator in a website.emulatorjs.org · read 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.emulatorjs.org · read 8 Oct 2026
- Support
- The project directs users to report issues on GitHub and include browser console logs and the version they use.github.com · read 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.emulatorjs.org · read 8 Oct 2026
