What coding language does Roblox use?

What is Luau? The Evolution of Roblox's Custom Engine

For over a decade, Roblox utilized standard vanilla Lua 5.1, a lightweight scripting language renowned in the gaming industry for its embedding capabilities (used in World of Warcraft, Civilization, and CryEngine).

However, as Roblox experiences evolved from simple physics simulations into massive multiplayer worlds hosting 100 concurrent players with millions of physical parts, vanilla Lua 5.1 reached performance bottlenecks.

To overcome these limitations, Roblox engineers created Luau—a completely modernized, open-source programming language with a brand-new compiler, rewritten garbage collector, and native type-checking system.

Key Features: Why Luau Beats Standard Lua 5.1

Luau introduces substantial technical enhancements while maintaining backward compatibility with Lua 5.1 syntax:

• •Gradual Strict Typing: Add type annotations (e.g., `local health: number = 100`) to catch logic bugs in Studio before running the game.
• •Compound Assignment Operators: Supports convenient shorthand like `x += 1`, `health -= 10`, and `score *= 2`.
• •Generalized Iteration: Loop through tables directly with `for i, v in myTable do` without needing `ipairs()` or `pairs()`.
• •Bytecode Compilation Optimization: The Luau compiler optimizes dead code elimination and inlines small functions automatically.

Luau Code Examples: Variables, Types & Events

Here is a demonstration of clean, modern Luau code implementing a lethal "Kill Brick" hazard with type safety:

--!strict
local part: BasePart = script.Parent :: BasePart

local function onTouch(hit: BasePart): ()
    local character: Model? = hit.Parent :: Model?
    if not character then return end
    
    local humanoid: Humanoid? = character:FindFirstChildOfClass("Humanoid")
    if humanoid and humanoid.Health > 0 then
        humanoid.Health = 0
    end
end

part.Touched:Connect(onTouch)

Client vs Server Architecture in Luau

Luau scripts execute within a strict client-server network replication hierarchy:

Server Scripts (Script): Run on Roblox cloud datacenter servers. They handle authoritative game logic, player health, money transactions, and saving DataStores.

Client Scripts (LocalScript): Run on the individual player's device (PC, phone, console). They handle user input (WASD, mouse clicks), local camera animations, and 2D user interfaces (Guis).

Communication between client and server is handled securely using RemoteEvents and RemoteFunctions.

Learning Roadmap for Beginners

If you are new to programming, Luau is one of the friendliest languages to learn because code changes produce immediate visual results in the 3D Studio viewport.

Begin by mastering Variables and Data Types (numbers, strings, booleans, vectors), advance to Conditional Statements (if/then/else) and Loops, and finally study the Roblox Object Hierarchy and Event Listeners (`:Connect()`).