luau: A small, fast, and embeddable programming language based on Lua with a grad
Posted: Wed Jul 15, 2026 3:44 pm
Luau is the language every Roblox script actually runs on. It started as a Lua 5.1 fork and grew into a fast, gradually typed language with its own analysis tools, and it is fully open source. Understanding Luau well is the single best investment a Roblox scripter can make.
What is luau?
A small, fast, and embeddable programming language based on Lua with a gradual type system.
Luau (lowercase u, /ˈlu.aʊ/) is a fast, small, safe, gradually typed embeddable scripting language derived from Lua. It is designed to be backwards compatible with Lua 5.1, as well as incorporating some features from future Lua releases, but also expands the feature set (most notably with type annotations and a state-of-the-art type inference system). Luau is largely implemented from scratch, with the language runtime being a very heavily modified version of Lua 5.1 runtime, with completely rewritten interpreter and other performance innovations. The runtime mostly preserves Lua 5.1 API, so existing bindings should be more or less compatible with a few caveats. Luau is used by Roblox game developers to write game code, and by Roblox engineers to implement large parts of the user-facing application code as well as portions of the editor (Roblox Studio) as plugins. Roblox chose to open-source Luau to foster collaboration within the Roblox community as well as to allow other companies and communities to benefit from the ongoing language and runtime innovation. More recently, Luau has seen adoption in games like Alan Wake 2, Farming Simulator 2025, Second Life, and Warframe.
The facts, straight from GitHub
- Repository: luau-lang/luau
- 5,691 stars and 607 forks, with 473 open issues
- Written mainly in C++
- Licensed under MIT
- Started in 2018, last updated 2026-07-14
Grab it with: git clone https://github.com/luau-lang/luau.git
You will need a C++ toolchain (Visual Studio on Windows or gcc/clang elsewhere) plus CMake if the project uses it. Check the README for exact build steps.
Frequently asked questions
Is luau free to use?
It is released under the MIT license, so it is free to use. Read the license text for the exact terms before you ship anything based on it.
Is the project still maintained?
Yes, the last update was pushed on 2026-07-14, so the project is alive and moving.
What do I need to know before diving in?
The project is written mainly in C++, so some familiarity there helps a lot. Start with the README, then browse the open issues to see what the rough edges are. That is usually the fastest way to understand the real state of any repository.
Where do I get help if I am stuck?
Open an issue on the GitHub issue tracker, check existing discussions, and of course post right here in this topic. Someone in the Roblox community has probably hit the same wall before you.
Over to you
Have you tried luau? Are you running it, forking it, or did you rage quit halfway through the setup? Reply below with your experience, your questions or your own favorite alternative. If there is enough interest we can put together a community guide for it.