Roblox and Luau

Roblox games are scripted in Luau, Roblox's Lua dialect, inside Roblox Studio. The language basics from this course carry over directly; what's new is the engine API.

Scripts and services

-- A Script in ServerScriptService
local Players = game:GetService("Players")

Players.PlayerAdded:Connect(function(player)
    local leaderstats = Instance.new("Folder")
    leaderstats.Name = "leaderstats"
    leaderstats.Parent = player

    local coins = Instance.new("IntValue")
    coins.Name = "Coins"
    coins.Value = 0
    coins.Parent = leaderstats
end)

-- A Script inside a Part: give a coin when touched
local part = script.Parent
local debounce = {}

part.Touched:Connect(function(hit)
    local player = Players:GetPlayerFromCharacter(hit.Parent)
    if player and not debounce[player] then
        debounce[player] = true
        player.leaderstats.Coins.Value += 1
        task.wait(1)
        debounce[player] = nil
    end
end)

• The game is a tree of Instances (game, Workspace, parts, folders); script.Parent is the object the script is inside.
• Events (PlayerAdded, Touched) take callbacks via :Connect — closures, as in Level 2.
• task.wait pauses the script — coroutines under the hood.

Client and server

• Scripts run on the server; LocalScripts run on each player's device (input, camera, UI).
• They communicate through RemoteEvents and RemoteFunctions.
• Never trust the client: validate every request on the server — exploiters can fire remotes with any arguments.
• ModuleScripts are Luau modules loaded with require, used to share code.

Luau features worth using

• Type annotations with --!strict catch bugs in Studio before you play.
• +=, continue, and string interpolation with backticks.
• Luau is fast (with native code generation) and sandboxed — os, io, and load are restricted.

The Roblox Creator Documentation (create.roblox.com/docs) has the full engine API and tutorials.