Garry's mod successor s&box goes open source and even opens up the finances, Garry says: 'Valve gave me my chance, I'm already rich, I don't want to f*ck anyone over'

Facepunch Studios has announced that s&box, the long-in-development successor to Garry's mod, is now open source. "We're awesome," says studio founder Garry Newman, which we'll nod through because they kind of are. "S&box code is on GitHub now (Valve's code is still closed source, we're not open sourcing that)."

s&box has been made open source under the MIT license, and this means developers can basically do whatever they like with it: "You can view, modify, copy any of our code to help improve s&box with pull requests, or maintain your own fork for your standalone games, or even just take the code for your own engine."

Facepunch then explains why it's doing this, and nails its own colours to the mast: "It might seem odd from a business perspective to make an engine and give it away for free with no royalties and to give all the code away under open source. But we're a bunch of nerds that love what we're creating, we want everyone to use it in whatever way they want, we want to provide opportunities."

Some more context on why Facepunch, and Newman, think like this: last week he announced that the studio was also going to open source the finances for s&box. "I don't think it's easy for people to comprehend what we're doing here so they're inevitably going to see everything as a cash grab," explains Newman.

"I feel like it's quite easy to create a community where everyone wins. Valve has done this repeatedly. They did it for me. They could have easily made Garry's mod themselves. They could have taken 100% of that money. They could have given me $100k for the rights. But they didn't, they knew that if you let people succeed it's good for them and it's good for you. Everybody wins.

"Valve gave me my chance. I'm already rich. I don't want to fuck anyone over. I want to give opportunities to the next generation, like Valve did me. We can all win together."

Facepunch describes s&box as "a spiritual successor to Garry’s Mod and a love letter to Source 2" but the link to Garry's mod can be a bit confusing. Gmod reframed and recontextualised Half-Life 2's assets into a (sorry) sandbox that allowed players to create games and scenarios using those tools. S&box has that same idea of flexibility at the core but is much more its own game engine and creation platform, with much greater potential for users.

"s&box isn’t Garry’s Mod 2," says Facepunch. "It’s built to eclipse what was possible before—not just modernise it." It goes on to describe it as "a modern, intuitive, moddable game development environment" and says it's something the studio intends to "work on and improve for the next couple of decades."

S&box was first unveiled in 2017 and was then an Unreal Engine 4 project. At the time Garry Newman told PCG "it's all done in an engine agnostic way. We can lift our system off and put it on the Source engine (it actually started on the Source engine)." Prophetic or what, because s&box now sits proudly atop Valve's Source 2 engine (and has for many years).

s&box has a Steam page and is scheduled to release on the platform in Q1 2026, though developers can get early access to it via the s&box website.

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