Boxroom Plus

Version 1.3.0

Boxroom Plus extends BOXROOM with support for custom applications, emulators, non-Steam games, and custom case appearance while protecting custom entries from Steam cache refreshes.

Unlike vanilla BOXROOM, Boxroom Plus allows custom AppIDs to behave like native Steam titles inside your library while adding additional metadata used for custom platforms and visual customization.

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Features

• Launch custom executables using launch.json
• Launch emulators with ROM arguments
• Launch non-Steam games
• Treat custom AppIDs as owned by Steam
• Prevent custom games from being removed during cache refreshes
• Prevent metadata invalidation for custom games
• Automatic fallback to Steam launching
• Custom platform metadata
• Automatic platform-specific case colors
• User-defined custom case colors
• Fully compatible with existing Steam titles

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Requirements

• BOXROOM
• MelonLoader
• .NET Framework compatible with BOXROOM

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Installing MelonLoader

1. Download MelonLoader from https://melonwiki.xyz
2. Run the installer.
3. Select BOXROOM.exe.
4. Install the latest stable version.
5. Launch BOXROOM once.
6. Verify the following folders exist:

BOXROOM/
├── Mods/
├── UserData/
└── MelonLoader/

7. Close BOXROOM.

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Installing Boxroom Plus

Copy:

BoxroomPlus.dll

into:

BOXROOM/Mods/

Launch BOXROOM.

If installed correctly you should see:

Boxroom Plus Loaded!

inside the MelonLoader console.

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How It Works

Steam Games

BOXROOM
    │
    ▼
Steam Launch

Custom Games

BOXROOM
    │
    ▼
launch.json Found?
    │
 ┌──┴─────┐
 │ Yes    │ No
 ▼        ▼
Launch    Steam
Executable Launch

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Custom AppIDs

Boxroom Plus patches BOXROOM's ownership validation so custom AppIDs are treated as owned.

This allows custom games to appear and launch normally without requiring a Steam license for the custom AppID.

Steam games continue using Steam's normal ownership validation.

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Cache Protection

During Steam cache refreshes BOXROOM may invalidate cached metadata.

Boxroom Plus skips invalidation for custom AppIDs, protecting:

• Custom metadata
• Custom helper metadata
• Custom launch configurations
• Imported custom games

This prevents custom entries from being removed during refresh operations.

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Custom Metadata

Boxroom Plus supports an optional helper file:

meta.helper.json

located alongside a game's metadata.

Example:

steam_cache_v2/
└── 900000001/
    ├── game.json
    ├── meta.helper.json
    ├── screenshots/
    └── launch.json

Example:

{
  "Type": "Custom",
  "Platform": "gog",
  "CaseColor": "#FFD700"
}

Supported Fields

Field	Description
Type	Optional application type.
Platform	Platform identifier used for automatic case colors.
CaseColor	Optional HTML color overriding the platform default.

If CaseColor is omitted, Boxroom Plus will automatically use the default color associated with the selected platform.

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launch.json

Place a launch.json file inside:

AppData\LocalLow\NestedLoop\BOXROOM\steam_cache_v2\<AppId>\

Example:

steam_cache_v2/
└── 900000001/
    ├── game.json
    ├── screenshots/
    └── launch.json

---

Example

{
  "Executable": "C:\\Games\\Minecraft\\MinecraftLauncher.exe",
  "Arguments": "",
  "WorkingDirectory": "C:\\Games\\Minecraft",
  "UseShellExecute": true
}

---

launch.json Fields

Executable

Required path to the executable.

Arguments

Optional command-line arguments.

WorkingDirectory

Optional working directory.

If omitted, Boxroom Plus automatically uses the executable's directory.

UseShellExecute

Optional.

Defaults to true.

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Linux / Steam Deck

Boxroom Plus works under Proton.

Steam launch requests function normally, however launching native Linux executables directly from Proton may not always work.

Recommended Workaround

1. Add the Linux application as a Non-Steam Game.
2. Create a desktop shortcut from Steam.
3. Open the generated .desktop file.
4. Copy the generated launch command into launch.json.

Steam will then handle launching the application correctly.

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Companion Application

Boxroom Studio

Boxroom Studio provides a graphical interface for managing custom games.

Features include:

• Create custom games
• Import metadata
• Download SteamGridDB artwork
• Download screenshots
• Generate and edit launch.json
• Configure platforms
• Configure custom case colors
• Manage helper metadata

GitHub:

https://github.com/MidgetBrony/Boxroom-Studio

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Planned

• Additional platform integrations
• Expanded metadata support
• Additional Linux improvements

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License

MIT License

💬 Discord

Join the Boxroom Modding community for support, development discussion, bug reports, feature requests, and sneak peeks of upcoming releases.

https://discord.gg/M2ebcaTEMe