EmulatorJS review
A broad, open-source browser emulator for embedded retro-system play, without current netplay.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
EmulatorJS is an open-source JavaScript framework for developers who want to embed playable retro-system emulation into websites. It uses RetroArch libretro cores compiled to WebAssembly and provides generated embed code for browser-based operation. The project also supports self-hosting on a web server, with platform coverage spanning web, iOS, Android, and self-hosted deployments. It is best suited to websites and digital projects that need configurable emulation rather than a standalone ROM-management server.
Its main strength is the breadth of the embedded feature set. EmulatorJS verifies support for 36 systems, including arcade systems, while offering ROM drag-and-drop loading, save-state saving and loading, screen recording, cheat-code menus, custom shaders, and browser cache management. Keyboard and controller mapping supports up to four players, and the interface is multilingual. RetroArch cores compiled to WebAssembly make the emulator suitable for browser delivery, while shader support adds room for visual customization. These capabilities give developers several control and presentation options within one embeddable component.
The key limitation is networked multiplayer: netplay is not currently supported, even though related documentation includes server setup instructions and the roadmap lists the feature as in development. That makes EmulatorJS a weaker fit for projects centered on online multiplayer sessions. Its JavaScript and WebAssembly foundation also places the emphasis on web integration and self-hosting, so teams seeking a native standalone emulator package or a dedicated ROM-management server should consider a different category of tool. Choose EmulatorJS when website embedding, broad system coverage, and customizable browser playback matter most.
EmulatorJS pros and cons
- Where it wins
- Embeddable WebAssembly RetroArch cores cover 36 systems.
- Includes save states, recording, cheats, shaders, and cache management.
- Maps keyboards and controllers for up to four players.
- Where it doesn't
- Netplay is not currently supported.
- Its scope centers on web embedding, not standalone ROM management.
- The JavaScript and WebAssembly approach suits web projects more than native apps.
EmulatorJS fact sheet, pricing and score →
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