RomM Browser-Based Emulation: Supported Platforms and Implementation Guide

Yes, RomM includes built-in browser-based emulation using two client-side engines: EmulatorJS for classic consoles (NES, SNES, Genesis, etc.) and RuffleRS for Adobe Flash content, both running entirely in the browser without server-side binaries.

RomM transforms your self-hosted game library into a playable archive by embedding browser-based emulation directly into its Vue.js frontend. According to the RomM source code, the platform ships with two self-contained emulation engines that stream ROM files directly to the client, eliminating the need for external plugins or server-side execution.

How RomM Implements Browser-Based Emulation

The RomM frontend implements a dual-engine architecture located in frontend/src/views/Player/. Each engine handles distinct platform categories and exposes a consistent JavaScript API for programmatic control.

EmulatorJS for Classic Consoles

EmulatorJS powers emulation for Nintendo Entertainment System, Super Nintendo, Sega Genesis, DOS, and other classic platforms. The core implementation resides in frontend/src/views/Player/EmulatorJS/Base.vue, a Vue component that injects the EJS script and instantiates a global window.EJS_emulator instance driving the HTML5 canvas.

The component loads the library from a CDN or bundled copy (controlled by EMULATORJS_VERSION) and manages the emulator lifecycle. For the v2 interface, this component is wrapped by frontend/src/v2/views/Player/EmulatorJS.vue.

RuffleRS for Flash Content

RuffleRS handles Adobe Flash and SWF files through the WebAssembly-based Ruffle emulator. The wrapper at frontend/src/views/Player/RuffleRS/Base.vue loads ruffle/ruffle.js from a CDN and creates a window.RufflePlayer singleton. The v2 shell reuses this component via frontend/src/v2/views/Player/Ruffle.vue.

Integration Architecture and Routing

RomM exposes browser-based play through dedicated URL routes defined in frontend/src/v2/router/routes.ts. When a user selects a ROM, the application navigates to platform-specific endpoints:

• /rom/:id/emulatorjs for EmulatorJS-supported platforms
• /rom/:id/ruffle for Flash content

The UI determines route availability using runtime helpers exported from frontend/src/utils/index.ts. The predicates isEJSEmulationSupported and isRuffleEmulationSupported evaluate the platform slug, server heartbeat, and configuration to decide whether to render the "Play in browser" button in frontend/src/components/common/Game/PlayBtn.vue.

Programmatic Control and API Usage

Because both engines expose global window objects, you can control emulation programmatically from TypeScript or JavaScript.

Checking Emulation Support

Before navigating to a player route, validate support using the utility functions:

import { isEJSEmulationSupported, isRuffleEmulationSupported } from '@/utils'

// Check if ROM supports browser-based emulation
if (isEJSEmulationSupported(rom.platform_slug, heartbeat.value, config.value)) {
  router.push(`/rom/${rom.id}/emulatorjs`)
}

// Check for Flash content
if (isRuffleEmulationSupported(rom.platform_slug, heartbeat.value, config.value)) {
  router.push(`/rom/${rom.id}/ruffle`)
}

Controlling the Emulator Instance

Once loaded, interact with the global emulator objects:

// Pause EmulatorJS
window.EJS_emulator?.pause()

// Toggle fullscreen (respects user preference "emulation.fullScreenOnPlay")
window.EJS_emulator?.toggleFullscreen(true)

// Save state in Ruffle
window.RufflePlayer?.newest()?.saveState?.()

Key Implementation Files

• frontend/src/views/Player/EmulatorJS/Base.vue – Core EmulatorJS player component
• frontend/src/views/Player/RuffleRS/Base.vue – Ruffle Flash player wrapper
• frontend/src/v2/views/Player/EmulatorJS.vue – v2 shell for EmulatorJS
• frontend/src/v2/views/Player/Ruffle.vue – v2 shell for Ruffle
• frontend/src/v2/router/routes.ts – Route definitions for /emulatorjs and /ruffle
• frontend/src/utils/index.ts – Runtime helpers isEJSEmulationSupported and isRuffleEmulationSupported
• frontend/src/components/common/Game/PlayBtn.vue – UI button logic for play availability

Summary

• RomM supports browser-based emulation through two embedded engines requiring no server-side binaries.
• EmulatorJS handles classic consoles via frontend/src/views/Player/EmulatorJS/Base.vue, exposing window.EJS_emulator.
• RuffleRS plays Flash content via frontend/src/views/Player/RuffleRS/Base.vue, exposing window.RufflePlayer.
• Runtime checks in frontend/src/utils/index.ts determine UI visibility for the "Play in browser" feature.
• ROMs stream directly to the client, with routes at /rom/:id/emulatorjs and /rom/:id/ruffle.

Frequently Asked Questions

Does RomM require server-side emulators for browser-based play?

No. RomM's browser-based emulation runs entirely client-side. The EmulatorJS and RuffleRS engines execute in the user's browser using WebAssembly and JavaScript, streamed directly from your RomM instance without requiring server-side binary execution or additional emulation software on the host.

Which platforms support browser-based emulation in RomM?

EmulatorJS supports NES, SNES, Genesis, DOS, and other classic platforms through the open-source EmulatorJS library. RuffleRS supports Adobe Flash and SWF files. The exact availability depends on the ROM's platform slug and your RomM configuration, checked via isEJSEmulationSupported and isRuffleEmulationSupported in frontend/src/utils/index.ts.

How do I check if a specific ROM supports browser play?

Use the utility functions exported from frontend/src/utils/index.ts. Pass the ROM's platform slug, the server heartbeat, and configuration object to isEJSEmulationSupported() or isRuffleEmulationSupported(). These return booleans indicating whether the UI should display the play button and enable navigation to the emulator routes.

Can I customize the emulator settings or behavior?

Yes. The EmulatorJS component respects configuration values such as EMULATORJS_VERSION for script loading and user preferences like emulation.fullScreenOnPlay. You can programmatically control the emulator through the global window.EJS_emulator API for pausing, fullscreen toggling, and save states, or use window.RufflePlayer for Flash-specific operations.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}