If you spend enough time in the developer forums, you'll eventually hear someone complaining about the roblox closed source nature and how it limits what creators can actually do. It's a valid point, especially when you look at the rest of the game dev world where engines like Godot are blowing up because they're completely open. But Roblox isn't just a game engine; it's a massive social ecosystem and a multi-billion dollar business, which makes the "open vs. closed" debate a lot more complicated than it looks on the surface.
Most people starting out on the platform don't really think about what's happening under the hood. They just open Studio, drag some parts around, write a few lines of Luau, and hit publish. But for the power users—the ones trying to squeeze every last drop of performance out of the engine—the fact that the core source code is locked away behind a digital vault can be pretty frustrating.
The security argument for staying closed
Let's talk about the elephant in the room first: security. One of the biggest reasons for the roblox closed source model is that it acts as a primary defense against exploits and hacking. Roblox already has a massive problem with "exploiters" who try to inject scripts, fly around maps, or ruin the economy of popular games. Now, imagine if those same people had the literal blueprint for how the engine handles networking, physics, and memory.
If Roblox went open source tomorrow, the community would probably find some amazing ways to optimize the engine within hours. However, the "bad actors" would also find every single vulnerability and back door in the system. Since Roblox hosts the servers and handles the transactions (Robux), they can't really afford to have the engine's guts exposed to everyone. They need that "black box" approach to keep some level of control over the environment.
It's a bit of a double-edged sword, though. Critics argue that "security through obscurity" isn't real security. They say that if the code were open, the community could actually help patch bugs and fix security holes faster than the internal Roblox team can. While that works for something like Linux, it's a much riskier bet for a platform that has millions of kids playing on it every day.
Protecting the intellectual property
From a purely business perspective, it makes sense why we have a roblox closed source situation. Roblox has spent over a decade building a proprietary cloud-based architecture. They aren't just selling you a game engine; they're selling you a "one-click publishing" service. When you make a game on Roblox, you don't have to worry about renting servers, setting up databases, or figuring out how to handle thousands of concurrent players. The engine handles all of that.
If they opened the source code, someone could theoretically take that engine, strip out the Roblox branding, and launch their own "Competitor-Blox" without having to do any of the R&D. By keeping the engine closed, Roblox ensures that their technology stays theirs. They've built a "walled garden," and while some people hate the walls, those walls are what keep the company's valuation high and its investors happy.
The Luau exception
Interestingly, Roblox isn't completely closed off. They've actually been surprisingly cool about their scripting language, Luau. A few years back, they made Luau open source, which was a huge deal. Luau is their specialized version of Lua, optimized for performance and with a bunch of type-checking features added in.
By making the language open source while keeping the roblox closed source engine, they found a middle ground. They let developers use the language for other projects, which helps the language grow and improve, but they still keep the engine's core secrets locked away. It's a "best of both worlds" strategy that shows they aren't totally against the open-source philosophy—they're just very selective about where they apply it.
Does it hold back performance?
This is where the debate gets heated. Because of the roblox closed source model, developers are stuck with whatever optimizations Roblox decides to prioritize. If you're building a massive open-world game and you notice that the way the engine handles Level of Detail (LOD) is inefficient, you can't just go in and rewrite that part of the C++ code. You have to write a "hacky" workaround in Luau or just wait for an official update.
In engines like Unreal or Godot, if a developer finds a bottleneck in the engine, they can just change the code. On Roblox, you're basically at the mercy of the weekly update cycle. This is why you see top-tier Roblox developers doing crazy things with "custom renderers" and complex math scripts—they're trying to bypass limitations that wouldn't even exist if they could just edit the engine directly.
That said, Roblox has been getting much better at listening to the community. They've been rolling out things like the "Parallel Luau" feature, which finally lets us take advantage of multi-core processors. It's not the same as having full access to the source code, but it's a step toward giving developers more power.
The simplicity for beginners
One thing we have to remember is that Roblox is designed to be accessible. If the platform wasn't a roblox closed source environment, it would likely be a lot more intimidating for the average twelve-year-old trying to make their first "Obby."
The closed nature allows Roblox to maintain a very specific "API" (Application Programming Interface). It's like a simplified dashboard. You don't need to know how the engine talks to your graphics card; you just need to know how to change the Transparency property of a Part. By hiding the complexity, Roblox makes game development feel more like playing with Legos and less like a computer science degree.
For a lot of people, that's the whole appeal. You can go from an idea to a live multiplayer game in literally ten minutes. You can't really do that in a fully open-source environment where you have to compile the engine and manage your own build pipelines.
Will things ever change?
It's highly unlikely that we'll ever see a fully open-source Roblox engine. The company is too big, the security risks are too high, and the business model depends too much on their proprietary tech. However, we are seeing a shift toward "Source Available" or "Open Tooling."
We're seeing more third-party tools like Rojo, which allows developers to use professional code editors like VS Code and sync their work into Roblox. This "pro-workflow" movement is bridges the gap between the roblox closed source limitations and the needs of professional studios.
Also, as the platform tries to attract more "AAA" style developers, they might be forced to open up more of the engine's internal settings. They might not give us the source code, but they might give us more "low-level" access than we have now.
Wrapping it up
At the end of the day, the roblox closed source engine is both a blessing and a curse. It's a curse because it limits the most talented developers and keeps them from truly optimizing their games to the professional standard seen in other engines. It's a blessing because it provides a safe, stable, and incredibly easy-to-use platform for millions of people who would never touch game dev otherwise.
Would it be cool to see the C++ code for the physics solver? Absolutely. Is it going to happen? Probably not. But as long as Roblox keeps updating the API and making the scripting environment more powerful, most of us will probably keep clicking that "Publish to Roblox" button anyway. The trade-off—free servers, an instant audience, and easy monetization—is just too good to pass up for most people, even if the engine remains a bit of a mystery.