Legal Questions/Concerns
MASHBOX is a game engine. Here is what we make, what we never ship, who owns everything else you see, and the open-source work we build on. Last updated 2026-10-07.
Summary
Our engine, our code
Every line we ship is our own or credited open source. No game content from anyone else is in MASHBOX.
We never ship games
We do not distribute, host, sell or stream any game, file or asset owned by another company.
Your copy, on your PC
MASHBOX works only with games you own and installed. Nothing from your games is uploaded.
Free
MASHBOX is free.
Your games
- MASHBOX looks for the game you installed and checks that its files are present and complete on your machine.
- You confirm that you own the game and use your own copy. MASHBOX does not continue without that confirmation.
- MASHBOX reads your files locally, on your own computer, so the engine can play them. Nothing from your game is uploaded to us or anyone else.
Multiplayer
Players connect directly or through a small service that helps them find each other. No game files or assets are sent between players or to our servers. Every player owns and installs the games they use.
Why it is lawful
MASHBOX is operated from and subject to the laws of the British Virgin Islands. Because most publishers are in the United States, we also explain the United States position, where the leading software and video game cases were decided.
United States
| Authority | Citation | What it holds |
|---|---|---|
| Baker v. Selden | 101 U.S. 99 (1879) | Ideas, systems and methods of play are free; copyright protects only specific expression. Codified in 17 U.S.C. section 102(b). |
| Google LLC v. Oracle America, Inc. | 593 U.S. 1 (2021), U.S. Supreme Court | Reimplementing an existing interface so new software works with what people already know is fair use. |
| Sega Enterprises Ltd. v. Accolade, Inc. | 977 F.2d 1510 (9th Cir. 1992) | Studying a system to make independent, compatible games is fair use, because it brings the public more creative works. |
| Sony Computer Entertainment, Inc. v. Connectix Corp. | 203 F.3d 596 (9th Cir. 2000) | A program that let people play the games they own on other hardware was fair use. |
| Lewis Galoob Toys, Inc. v. Nintendo of America, Inc. | 964 F.2d 965 (9th Cir. 1992) | Changing how a player's own copy of a game behaves, for their own play, did not infringe. |
| 17 U.S.C. section 117 | U.S. Copyright Act | The owner of a copy of a program may make the copies and adaptations needed to run it on their own machine. |
| 17 U.S.C. section 1201(f) | U.S. Copyright Act | Analysing a program to make an independently created program work with it is expressly permitted. |
How MASHBOX follows these rules
- We ship only our own code and properly licensed open source. Nothing from any game is distributed, hosted or sold by us. That is the line the courts drew between Galoob (lawful) and Micro Star v. FormGen, 154 F.3d 1107 (9th Cir. 1998), where a company sold discs of game content.
- Every game is the player's own lawfully obtained copy, checked by our software and confirmed by the player.
- Everything runs locally, for the player's own play.
British Virgin Islands
The Territory's copyright law protects authors' works and recognises acts that owners cannot forbid, in the tradition of English law. That tradition expressly permits a lawful user of a program to make the copies needed to use it, and to study how it works so that independent programs can operate with it. MASHBOX is built to that standard: our engine is independently written, works only with each player's own copy, and distributes nothing that belongs to anyone else.
Ownership of games and marks
All game titles, characters, names and logos belong to their owners. MASHBOX is not affiliated with, endorsed by or sponsored by any of them. We use names only to tell you which of your installed games our engine works with.
| Game or mark | Owner |
|---|---|
| Call of Duty, Modern Warfare 2, Black Ops, Call of Duty 4 | Activision Publishing, Inc. |
| Halo, Halo: Combat Evolved, Halo 2 | Microsoft Corporation |
| Minecraft, Steve | Mojang AB / Microsoft Corporation |
| The Elder Scrolls V: Skyrim, Fallout 3, Fallout 4, Fallout: New Vegas | Bethesda Softworks LLC / ZeniMax Media Inc. |
| Fortnite | Epic Games, Inc. |
| Skate 3, Mirror's Edge | Electronic Arts Inc. |
| Grand Theft Auto V, San Andreas, IV | Take-Two Interactive Software, Inc. / Rockstar Games |
| Resident Evil 4, Resident Evil Village | Capcom Co., Ltd. |
| Marvel's Spider-Man | Sony Interactive Entertainment / Marvel |
| Elden Ring | FromSoftware, Inc. / Bandai Namco Entertainment |
| Cyberpunk 2077 | CD PROJEKT S.A. |
| World of Warcraft | Blizzard Entertainment, Inc. |
| Super Mario 64, Super Smash Bros. Melee | Nintendo Co., Ltd. |
| Portal 2, Steam | Valve Corporation |
| Nazi Zombies: Portable | The NZ:P Team (CC BY-SA 4.0) |
Open source we use
MASHBOX is built on the work of these projects. Thank you to every author and contributor. Each keeps its own licence and we follow its terms. For each one we recorded the version we checked, the licence it carried on that date, a copy of that licence and a dated screenshot of its GitHub page. We review every project before it enters our engine. The Rust libraries compiled into the engine are listed inside it (licenses command).
Proof of date
The SHA-256 fingerprints of every screenshot, licence copy and the ledger are in SHA256SUMS, timestamped on the Bitcoin blockchain through OpenTimestamps: SHA256SUMS.ots.
Contact
If you own a mark or work and have a question or concern, write to legal@mashbox.gg and we will respond promptly.
This page explains how MASHBOX works. It is not legal advice to you.