Game engine
s&box
s&box is Facepunch's Source 2 game platform. You build in C# on Windows and publish through s&box.
Developer: Facepunch Studios
C# 3D on WindowsGames that can live on s&boxMultiplayer prototypes
Overview
The interesting part is C# on a Source 2 renderer, with multiplayer as a normal case rather than a plugin you hope works.
It is not a general export engine. If the game has to leave the platform, this is the wrong starting point.
Technical specifications
Specs checked 2026-10-05. Version lines move; the download link is the source of truth.
- Developer
- Facepunch Studios
- Version line
- Current release
- License
- Proprietary
- Business model
- s&box is Facepunch's platform. The engine is not an MIT download. Read the current publishing terms on sbox.game before you treat a game as yours to sell elsewhere.
- Releases
- The platform updates in place. Pin nothing until the current docs say a version is stable for shipping.
- Editor platforms
- Windows
- Export targets
- Windows
- Languages
- C#
- 2D / 3D
- 3D
- VR
- VR is part of the Source 2 toolset in s&box. Check the current docs for supported headsets.
- AR
- No.
- Visual scripting
- No. Games are C#.
- Beginners
- Mixed. C# and the editor are approachable. The platform terms and the Windows-only tools are the catch.
- Learning curve
- Moderate if you know C#. You are learning a platform, not only an API.
- Graphics
- Source 2 rendering: 3D scenes, materials, and lighting at a high desktop bar.
- Team size
- Small teams shipping inside the s&box platform.
- GitHub stars
- Not published as a public star count
- Documentation
- https://sbox.game/dev
- Community
- https://sbox.game
- Assets and examples
- https://sbox.game
- Download
- https://sbox.game
Where it fits
- C# with a high-end 3D renderer.
- Multiplayer is part of the platform story.
- The editor is aimed at making a game, not only a tech demo.
Where it does not
- Proprietary platform terms. Read them.
- Windows is the development machine.
- You are not picking a portable MIT runtime.
Matching source
No sample projects are listed for this engine yet.
How does it compare?
C# with exports outside a single platform.
MIT C# and a 3D editor if the platform terms are wrong.
Questions
Is s&box open source?
No. It is Facepunch's platform. Do not describe it as MIT.
What language is it?
C#.
Can I export to mobile or consoles?
Do not plan on that. The target is the s&box platform on PC.
Ad