Overview

Serotonin runs scripts on a sandboxed LuaJIT 2.0.3 core (which implements Lua 5.1), with the LuaJIT-specific globals stripped. _VERSION reports "Lua 5.1" because that is the language version LuaJIT 2.0.3 implements. jit, ffi, os, io, debug are stripped from the sandbox. string.buffer and the buffer table are not present - that API only landed in LuaJIT 2.1, while this build is on the older 2.0.3. The BitOp bit library is exposed (band, bor, bxor, bnot, lshift, rshift, arshift, rol, ror, bswap, tobit, tohex) - verified live. Scripts go in C:\Serotonin\scripts\*.lua and are loaded via the Scripting tab. Files written by scripts via the file library land in C:\Serotonin\files\ (sandboxed).

Lifecycle

A script registers callbacks via cheat.Register(event, fn). Available events:

Event	Frequency (verified live)	Use for
onUpdate	~10 ms (~95–100 Hz) cache thread	Logic, polling cached state
onSlowUpdate	exactly 1 s	Background tasks, timers
paint (alias onPaint)	per frame, ~60–250 Hz depending on display & cheat load; fires regardless of overlay focus	Drawing, required for any draw.* call
shutdown	once on unload	Cleanup
newPlace	place change	Reset state when teleporting

Both paint and onPaint aliases dispatch to the same per-frame slot - registering callbacks under both names doubles the callback rate (verified: 2 handlers → 2 calls per frame).

Note: cheat.Register does no validation on the event name string - passing an unknown name (or a number) is silently accepted. Only the five names above are actually dispatched.

cheat.register("onPaint", function()
    draw.TextOutlined("hello", 20, 20, Color3.fromRGB(255, 255, 255), "Verdana")
end)

Naming convention

Verified live by sweeping all 177 documented functions, userdata methods, and statics across five case-styles: PascalCase, camelCase, snake_case, full-lowercase, and SCREAMING_SNAKE_CASE.

Aggregate result (177 entries probed):

Style	Bound	Notes
PascalCase (GetTickCount)	164 / 177	The default. The only library where PC is not bound is file (see below).
camelCase (getTickCount)	169 / 177	The most universally accepted form. Always paired with PascalCase.
snake_case (get_tick_count)	163 / 177	Almost always bound for normal compound names. Breaks on multi-letter abbreviations (see edge cases below).
lowercase (gettickcount)	79 / 177	Only single-word names + the file library + a handful of "compound-looking-but-treated-as-one-word" names.
SCREAMING_SNAKE_CASE (GET_TICK_COUNT)	0 / 177	Never bound anywhere.

The general rule: for a normal compound name like GetTickCount, the cheat binds PascalCase + camelCase + snake_case (3 forms). Single-word names like Read collapse to PascalCase + lowercase (2 effective forms — for them lowercase = camelCase = snake_case).

PascalCase	camelCase	snake_case
utility.GetTickCount	utility.getTickCount	utility.get_tick_count
entity.GetPlayers	entity.getPlayers	entity.get_players
ui.NewCheckbox	ui.newCheckbox	ui.new_checkbox
draw.RectFilled	draw.rectFilled	draw.rect_filled
instance:FindFirstChild	instance:findFirstChild	instance:find_first_child
instance:GetAttributes	instance:getAttributes	instance:get_attributes
player:GetBonePosition	player:getBonePosition	player:get_bone_position

Edge cases (verified live)

These deviate from the general rule. When in doubt, default to PascalCase:

• file library is lowercase-canonical. file.read, file.write, file.append, file.listdir, file.exists, file.isdir, file.mkdir, file.delete — these are the canonical names. PascalCase variants (file.Read, file.Write, file.Append, file.Exists, file.Delete) are not bound, but they are exposed under the lowercase form only (and Read/Write/Append/Exists/Delete also have camelCase + snake_case forms).
• file.ListDir / IsDir / MkDir are bound only as file.listdir / file.isdir / file.mkdir (treated as single words by the cheat). The camelCase (listDir) and snake_case (list_dir) forms are not bound.
• Multi-letter abbreviations like RGB, HSV, FFlag survive only through PascalCase and camelCase. The snake_case form that would split each capital (from_r_g_b, to_h_s_v, set_f_flag) is not bound:
  • Color3.fromRGB / Color3.fromHSV / Color3:ToHSV exist at PascalCase + camelCase only.
  • game.SetFFlag / game.GetFFlag exist at PascalCase + camelCase only.
• Vector3.zero / .one / .xAxis / .yAxis / .zAxis are pre-allocated Vector3 userdata properties, not functions. They live at exactly the names listed (PascalCase / camelCase as written) — they have no aliases because they are values, not callables.
• SCREAMING_SNAKE_CASE is never bound anywhere. 0 of 177 probes returned a function under the screaming form.

This documentation uses PascalCase as canonical for cheat-side libraries (and lowercase for file). Use whichever style matches your codebase, but never reach for SCREAMING_SNAKE_CASE — it does not exist on any function.

Aliases are not the same Lua function object

Verified live: cheat.Register == cheat.register returns false, even though both call the same C function and behave identically. Each alias form is registered as a distinct Lua callable wrapping the same native handler. Do not use == to test whether a value is a specific API function, compare names instead.

Sandbox surface

Available globals

ui  string  mouse  http  table  type  next  pairs  ipairs  getmetatable  setmetatable
getfenv  setfenv  rawget  rawset  rawequal  unpack  select  tonumber  tostring  error
pcall  xpcall  loadfile  load  loadstring  dofile  gcinfo  collectgarbage  newproxy
print  _VERSION  coroutine  package  entity  websocket  audio  memory
file  keyboard  Color3  math  game  cheat  bit  draw  utility  Vector3  module  assert
require

Confirmed missing (return nil)

_G  _ENV  workspace  shared  typeof  tick  time  delay  spawn  wait  task  script
Instance  Enum  CFrame  Vector2  UDim  UDim2  Rect  TweenInfo  Region3  Ray  BrickColor
NumberRange  NumberSequence  ColorSequence  PhysicalProperties  Axes  Faces
os  io  debug  bit32  utf8  rawlen  jit  ffi  buffer  raknet  string.buffer

buffer and raknet were exposed in some earlier builds but are not bound in the current build (verified live: type(buffer) == "nil", type(raknet) == "nil"). Their doc pages have been removed - there is nothing usable to document.

Use getfenv(1) to get the current environment table.

Userdata vs table

• Tables: every API library (utility, memory, entity, ...) is a Lua table you index with ..
• Userdata: returned by API calls (Vector3, Color3, Roblox Instance, entity.GetPlayers() players, parts from entity.GetParts()). Methods on userdata are called with : and live in the metatable.

local v = Vector3.new(1, 2, 3)
print(v.X, v.Y, v.Z, v.Magnitude)
print(v:Lerp(Vector3.new(10, 0, 0), 0.5))

Calling Roblox services

game.GetService uses dot syntax, not colon:

local players  = game.GetService("Players")
local lighting = game.GetService("Lighting")

Confirmed working services (verified live): Players, Lighting, Workspace, HttpService, RunService, TeleportService, TextService, GamepadService, UserInputService, ReplicatedStorage, StarterGui, StarterPack, Stats, MarketplaceService. ServerStorage returns nil (not exposed to client).

⚠️ Direct game.<Service> is only pre-resolved for Workspace, Players, LocalPlayer. Even game.Lighting returns nil, you must use game.GetService("Lighting").

What to read next

1. Crash triggers, what to never touch
2. utility, first library reference
3. For LLMs, drop-in resources for AI agents

Documentation status

This site is filled in incrementally. Each library page is published only after every signature on it has been verified in a live sandbox.

Component	Status
utility library reference	Published
Other 15 libraries	In progress
Userdata type docs	Pending
Runnable examples	Pending
llms-full.md consolidated	Pending