What is Luau?

What Luau is

Luau is the scripting language used in Roblox, derived from Lua 5.1 with added types and performance work. It is the language that runs Roblox game logic, from combat and shops to saving player data.

Lua is a small scripting language created in 1993 at a university in Rio de Janeiro, Brazil. Roblox chose Lua as its scripting language early on and used version 5.1 for many years. As games on the platform grew bigger, Roblox needed faster code and better tools for large projects.

Roblox rewrote the language tooling in house and named the result Luau. It kept compatibility with Lua 5.1 code while adding a type system, new syntax and a faster interpreter. In 2021 Roblox released Luau as open source under the MIT license, so it can now be used outside Roblox as well.

How Luau works

Luau is a scripting language, which means it is embedded inside a larger program and controls what that program does. In Roblox, the engine handles graphics, physics and networking, and your Luau code tells it what should happen. You write variables, functions, loops and if statements, like in most languages.

The main data structure is the table. A table can act as a list, as a dictionary of keys and values, or as an object. Almost everything in a Luau program is built from tables and functions. Modules are files that return a table of functions, and other scripts load them with require.

Luau adds optional type checking on top of Lua. You can write code with no types at all, or you can add type annotations so the editor warns you about mistakes before the game runs. This is called gradual typing. Luau also runs code in a sandbox, which means scripts cannot reach outside the areas the host program allows.

Key features of Luau

• Gradual typing

  Types are optional. You can add them file by file and get warnings about wrong arguments or missing fields as you type.

• Lua 5.1 compatible

  Most Lua 5.1 code runs in Luau without changes. Skills and tutorials from Lua carry over.

• Faster execution

  Luau has its own compiler and interpreter, tuned for speed. This matters for games that run a lot of logic every frame.

• Modern syntax

  Luau adds things Lua 5.1 lacks, such as compound assignment like +=, a continue statement, string interpolation and if expressions.

• Sandboxing

  The language is designed to run untrusted code safely. Scripts only get the libraries the host chooses to expose.

• Open source

  The compiler, runtime and type checker are public under the MIT license and can be embedded in other programs.

When to use Luau

Luau compared with alternatives

How to start learning Luau

1. 01Install Roblox Studio, since it is the easiest place to write and run Luau.
2. 02Read the scripting fundamentals in the Roblox Creator Docs to learn variables, functions, loops and tables.
3. 03Write a small script, such as a part that disappears when a player touches it and comes back after a few seconds.
4. 04Move shared code into a ModuleScript and load it with require to learn how projects are organized.
5. 05Read the guides on luau.org and turn on strict type checking in one script to see how types catch mistakes.

What Luau costs

Luau is free and open source under the MIT license. You can use it in personal and commercial projects without paying anything. Using it inside Roblox is also free, though Roblox has its own terms for publishing and earning.

How DATAL Projects uses Luau

Luau is part of our game development work in the Philippines. Common uses:

• Roblox gameplay systems
• Server-side validation and anti-exploit checks
• Player data and progression

Common questions about Luau