diff --git a/src/create.luau b/src/create.luau
index 736ed26..d534ebe 100644
--- a/src/create.luau
+++ b/src/create.luau
@@ -2,6 +2,7 @@ if not game then script = require "test/relative-string" end
 local typeof = game and typeof or require "test/mock".typeof:: never
 local Instance = game and Instance or require "test/mock".Instance :: never
 
+local types = require(script.Parent.types)
 local throw = require(script.Parent.throw)
 local defaults = require(script.Parent.defaults)
 local apply = require(script.Parent.apply)
@@ -45,30 +46,30 @@ end
 type Props = { [any]: any }
 return (create :: any) :: 
 ( <T>(T & Instance) -> (Props) -> T ) &
-( ("Folder") -> (Props) -> Folder ) &
-( ("BillboardGui") -> (Props) -> BillboardGui ) &
-( ("CanvasGroup") -> (Props) -> CanvasGroup ) &
-( ("Frame") -> (Props) -> Frame ) &
-( ("ImageButton") -> (Props) -> ImageButton ) &
-( ("ImageLabel") -> (Props) -> ImageLabel ) &
-( ("ScreenGui") -> (Props) -> ScreenGui ) &
-( ("ScrollingFrame") -> (Props) -> ScrollingFrame ) &
-( ("SurfaceGui") -> (Props) -> SurfaceGui ) &
-( ("TextBox") -> (Props) -> TextBox ) &
-( ("TextButton") -> (Props) -> TextButton ) &
-( ("TextLabel") -> (Props) -> TextLabel ) &
-( ("UIAspectRatioConstraint") -> (Props) -> UIAspectRatioConstraint ) &
-( ("UICorner") -> (Props) -> UICorner ) &
-( ("UIGradient") -> (Props) -> UIGradient ) &
-( ("UIGridLayout") -> (Props) -> UIGridLayout ) &
-( ("UIListLayout") -> (Props) -> UIListLayout ) &
-( ("UIPadding") -> (Props) -> UIPadding ) &
-( ("UIPageLayout") -> (Props) -> UIPageLayout ) &
-( ("UIScale") -> (Props) -> UIScale ) &
-( ("UISizeConstraint") -> (Props) -> UISizeConstraint ) &
-( ("UIStroke") -> (Props) -> UIStroke ) &
-( ("UITableLayout") -> (Props) -> UITableLayout ) &
-( ("UITextSizeConstraint") -> (Props) -> UITextSizeConstraint ) &
-( ("VideoFrame") -> (Props) -> VideoFrame ) &
-( ("ViewportFrame") -> (Props) -> ViewportFrame ) &
+( ("Folder") -> (types.FolderProps) -> Folder ) &
+( ("BillboardGui") -> (types.BillboardGuiProps) -> BillboardGui ) &
+( ("CanvasGroup") -> (types.CanvasGroupProps) -> CanvasGroup ) &
+( ("Frame") -> (types.FrameProps) -> Frame ) &
+( ("ImageButton") -> (types.ImageButtonProps) -> ImageButton ) &
+( ("ImageLabel") -> (types.ImageLabelProps) -> ImageLabel ) &
+( ("ScreenGui") -> (types.ScreenGuiProps) -> ScreenGui ) &
+( ("ScrollingFrame") -> (types.ScrollingFrameProps) -> ScrollingFrame ) &
+( ("SurfaceGui") -> (types.SurfaceGuiProps) -> SurfaceGui ) &
+( ("TextBox") -> (types.TextBoxProps) -> TextBox ) &
+( ("TextButton") -> (types.TextButtonProps) -> TextButton ) &
+( ("TextLabel") -> (types.TextLabelProps) -> TextLabel ) &
+( ("UIAspectRatioConstraint") -> (types.UIAspectRatioConstraintProps) -> UIAspectRatioConstraint ) &
+( ("UICorner") -> (types.UICornerProps) -> UICorner ) &
+( ("UIGradient") -> (types.UIGradientProps) -> UIGradient ) &
+( ("UIGridLayout") -> (types.UIGridLayoutProps) -> UIGridLayout ) &
+( ("UIListLayout") -> (types.UIListLayoutProps) -> UIListLayout ) &
+( ("UIPadding") -> (types.UIPaddingProps) -> UIPadding ) &
+( ("UIPageLayout") -> (types.UIPageLayoutProps) -> UIPageLayout ) &
+( ("UIScale") -> (types.UIScaleProps) -> UIScale ) &
+( ("UISizeConstraint") -> (types.UISizeConstraintProps) -> UISizeConstraint ) &
+( ("UIStroke") -> (types.UIStrokeProps) -> UIStroke ) &
+( ("UITableLayout") -> (types.UITableLayoutProps) -> UITableLayout ) &
+( ("UITextSizeConstraint") -> (types.UITextSizeConstraintProps) -> UITextSizeConstraint ) &
+( ("VideoFrame") -> (types.VideoFrameProps) -> VideoFrame ) &
+( ("ViewportFrame") -> (types.ViewportFrameProps) -> ViewportFrame ) &
 ( (string) -> (Props) -> Instance )
diff --git a/src/types.luau b/src/types.luau
new file mode 100644
index 0000000..0d182e5
--- /dev/null
+++ b/src/types.luau
@@ -0,0 +1,357 @@
+if not game then
+	script = require("test/relative-string")
+end
+
+type Prop<T> = T? | () -> T?
+
+-- Creatable instances
+
+export type FolderProps = InstanceProps
+
+export type BillboardGuiProps = LayerCollectorProps & {
+	Active: Prop<boolean>,
+	Adornee: Prop<Instance>,
+	AlwaysOnTop: Prop<boolean>,
+	Brightness: Prop<number>,
+	ClipsDescendants: Prop<boolean>,
+	DistanceLowerLimit: Prop<number>,
+	DistanceStep: Prop<number>,
+	DistanceUpperLimit: Prop<number>,
+	ExtentsOffset: Prop<Vector3>,
+	ExtentsOffsetWorldSpace: Prop<Vector3>,
+	LightInfluence: Prop<number>,
+	MaxDistance: Prop<number>,
+	PlayerToHideFrom: Prop<Instance>,
+	Size: Prop<UDim2>,
+	SizeOffset: Prop<Vector2>,
+	StudsOffset: Prop<Vector3>,
+	StudsOffsetWorldSpace: Prop<Vector3>,
+}
+
+export type CanvasGroupProps = GuiObjectProps & {
+	GroupColor3: Prop<Color3>,
+	GroupTransparency: Prop<number>,
+}
+
+export type FrameProps = GuiObjectProps & {
+	Style: Prop<Enum.FrameStyle>,
+}
+
+export type ImageButtonProps = GuiButtonProps & ImageProps & {
+	HoverImage: Prop<string>,
+	PressedImage: Prop<string>,
+}
+
+export type ImageLabelProps = GuiObjectProps & ImageProps
+
+export type ScreenGuiProps = LayerCollectorProps & {
+	ClipToDeviceSafeArea: Prop<boolean>,
+	DisplayOrder: Prop<number>,
+	IgnoreGuiInset: Prop<boolean>,
+	SafeAreaCompatibilityMode: Prop<Enum.SafeAreaCompatibility>,
+	ScreenInsets: Prop<Enum.ScreenInsets>,
+}
+
+export type ScrollingFrameProps = GuiObjectProps & {
+	AutomaticCanvasSize: Prop<Enum.AutomaticSize>,
+	BottomImage: Prop<string>,
+	CanvasPosition: Prop<Vector2>,
+	CanvasSize: Prop<UDim2>,
+	ElasticBehavior: Prop<Enum.ElasticBehavior>,
+	HorizontalScrollBarInset: Prop<Enum.ScrollBarInset>,
+	MidImage: Prop<string>,
+	ScrollBarImageColor3: Prop<Color3>,
+	ScrollBarImageTransparency: Prop<number>,
+	ScrollBarThickness: Prop<number>,
+	ScrollingDirection: Prop<Enum.ScrollingDirection>,
+	ScrollingEnabled: Prop<boolean>,
+	TopImage: Prop<string>,
+	VerticalScrollBarInset: Prop<Enum.ScrollBarInset>,
+	VerticalScrollBarPosition: Prop<Enum.VerticalScrollBarPosition>,
+}
+
+export type SurfaceGuiProps = LayerCollectorProps & {
+	Active: Prop<boolean>,
+	Adornee: Prop<Instance>,
+	AlwaysOnTop: Prop<boolean>,
+	Brightness: Prop<number>,
+	CanvasSize: Prop<Vector2>,
+	ClipsDescendants: Prop<boolean>,
+	Face: Prop<Enum.NormalId>,
+	LightInfluence: Prop<number>,
+	MaxDistance: Prop<number>,
+	PixelsPerStud: Prop<number>,
+	SizingMode: Prop<Enum.SurfaceGuiSizingMode>,
+	ToolPunchThroughDistance: Prop<number>,
+	ZOffset: Prop<number>,
+}
+
+export type TextLabelProps = GuiObjectProps & TextProps
+
+export type TextButtonProps = GuiButtonProps & TextProps
+
+export type TextBoxProps = GuiObjectProps & TextProps & {
+	ClearTextOnFocus: Prop<boolean>,
+	CursorPosition: Prop<number>,
+	MultiLine: Prop<boolean>,
+	PlaceholderColor3: Prop<Color3>,
+	PlaceholderText: Prop<string>,
+	SelectionStart: Prop<number>,
+	ShowNativeInput: Prop<boolean>,
+	TextEditable: Prop<boolean>,
+
+	FocusLost: ((enterPressed: boolean, inputThatCausedFocusLoss: InputObject) -> ())?,
+	Focused: (() -> ())?,
+	ReturnPressedFromOnScreenKeyboard: (() -> ())?,
+}
+
+export type VideoFrameProps = GuiObjectProps & {
+	Looped: Prop<boolean>,
+	Playing: Prop<boolean>,
+	TimePosition: Prop<number>,
+	Video: Prop<string>,
+	Volume: Prop<number>,
+
+	DidLoop: ((video: string) -> ())?,
+	Ended: ((video: string) -> ())?,
+	Loaded: ((video: string) -> ())?,
+	Paused: ((video: string) -> ())?,
+	Played: ((video: string) -> ())?,
+}
+
+export type ViewportFrameProps = GuiObjectProps & {
+	Ambient: Prop<Color3>,
+	CurrentCamera: Prop<Camera>,
+	ImageColor3: Prop<Color3>,
+	ImageTransparency: Prop<number>,
+	LightColor: Prop<Color3>,
+	LightDirection: Prop<Vector3>,
+}
+
+-- Creatable UI modifiers
+
+export type UIAspectRatioConstraintProps = InstanceProps & {
+	AspectRatio: Prop<number>,
+	AspectType: Prop<Enum.AspectType>,
+	DominantAxis: Prop<Enum.DominantAxis>,
+}
+
+export type UICornerProps = InstanceProps & {
+	CornerRadius: Prop<UDim>,
+}
+
+export type UIGradientProps = InstanceProps & {
+	Color: Prop<ColorSequence>,
+	Enabled: Prop<boolean>,
+	Offset: Prop<number>,
+	Rotation: Prop<number>,
+	Transparency: Prop<NumberSequence>,
+}
+
+export type UIGridLayoutProps = UIGridStyleLayoutProps & {
+	CellPadding: Prop<UDim2>,
+	CellSize: Prop<UDim2>,
+	FillDirectionMaxCells: Prop<number>,
+	StartCorner: Prop<Enum.StartCorner>,
+}
+
+export type UIListLayoutProps = UIGridStyleLayoutProps & {
+	Padding: Prop<UDim>,
+}
+
+export type UIPaddingProps = InstanceProps & {
+	PaddingBottom: Prop<UDim>,
+	PaddingLeft: Prop<UDim>,
+	PaddingRight: Prop<UDim>,
+	PaddingTop: Prop<UDim>,
+}
+
+export type UIPageLayoutProps = UIGridStyleLayoutProps & {
+	Animated: Prop<boolean>,
+	Circular: Prop<boolean>,
+	EasingDirection: Prop<Enum.EasingDirection>,
+	EasingStyle: Prop<Enum.EasingStyle>,
+	GamepadInputEnabled: Prop<boolean>,
+	Padding: Prop<UDim>,
+	ScrollWheelInputEnabled: Prop<boolean>,
+	TouchInputEnabled: Prop<boolean>,
+	TweenTime: Prop<number>,
+
+	PageEnter: ((page: any) -> ())?,
+	PageLeave: ((page: any) -> ())?,
+	Stopped: ((currentPage: any) -> ())?,
+}
+
+export type UIScaleProps = InstanceProps & {
+	Scale: Prop<number>,
+}
+
+export type UISizeConstraintProps = InstanceProps & {
+	MaxSize: Prop<Vector2>,
+	MinSize: Prop<Vector2>,
+}
+
+export type UIStrokeProps = InstanceProps & {
+	ApplyStrokeMode: Prop<Enum.ApplyStrokeMode>,
+	Color: Prop<Color3>,
+	Enabled: Prop<boolean>,
+	LineJoinMode: Prop<Enum.LineJoinMode>,
+	Thickness: Prop<number>,
+	Transparency: Prop<number>,
+}
+
+export type UITableLayoutProps = UIGridStyleLayoutProps & {
+	FillEmptySpaceColumns: Prop<boolean>,
+	FillEmptySpaceRows: Prop<boolean>,
+	MajorAxis: Prop<Enum.TableMajorAxis>,
+	Padding: Prop<UDim2>,
+}
+
+export type UITextSizeConstraintProps = InstanceProps & {
+	MaxTextSize: Prop<number>,
+	MinTextSize: Prop<number>,
+}
+
+-- Helpers
+
+type ImageProps = {
+	Image: Prop<string>,
+	ImageColor3: Prop<Color3>,
+	ImageRectOffset: Prop<Vector2>,
+	ImageRectSize: Prop<Vector2>,
+	ImageTransparency: Prop<number>,
+	ResampleMode: Prop<Enum.ResamplerMode>,
+	ScaleType: Prop<Enum.ScaleType>,
+	SliceCenter: Prop<Rect>,
+	SliceScale: Prop<number>,
+	TileSize: Prop<UDim2>,
+}
+
+type TextProps = {
+	Font: Prop<Enum.Font>,
+	FontFace: Prop<Font>,
+	LineHeight: Prop<number>,
+	MaxVisibleGraphemes: Prop<number>,
+	RichText: Prop<string>,
+	Text: Prop<string>,
+	TextColor3: Prop<Color3>,
+	TextDirection: Prop<Enum.TextDirection>,
+	TextScaled: Prop<boolean>,
+	TextSize: Prop<number>,
+	TextStrokeColor3: Prop<Color3>,
+	TextStrokeTransparency: Prop<number>,
+	TextTransparency: Prop<number>,
+	TextTruncate: Prop<Enum.TextTruncate>,
+	TextWrapped: Prop<boolean>,
+	TextXAlignment: Prop<Enum.TextXAlignment>,
+	TextYAlignment: Prop<Enum.TextYAlignment>,
+}
+
+-- Base instance types
+
+type InstanceProps = {
+	[any]: any,
+
+	Archivable: Prop<boolean>,
+	Name: Prop<string>,
+	Parent: Prop<Instance>,
+
+	AncestryChanged: ((child: Instance, parent: Instance?) -> ())?,
+	AttributeChanged: ((attribute: string) -> ())?,
+	Changed: ((property: string) -> ())?,
+	ChildAdded: ((child: Instance) -> ())?,
+	ChildRemoved: ((child: Instance) -> ())?,
+	DescendantAdded: ((descendant: Instance) -> ())?,
+	DescendantRemoving: ((descendant: Instance) -> ())?,
+	Destroying: (() -> ())?,
+}
+
+type GuiBase2dProps = InstanceProps & {
+	AutoLocalize: Prop<boolean>,
+	Localize: Prop<boolean>,
+	RootLocalizationTable: Prop<LocalizationTable>,
+	SelectionBehaviorDown: Prop<Enum.SelectionBehavior>,
+	SelectionBehaviorLeft: Prop<Enum.SelectionBehavior>,
+	SelectionBehaviorRight: Prop<Enum.SelectionBehavior>,
+	SelectionBehaviorUp: Prop<Enum.SelectionBehavior>,
+	SelectionGroup: Prop<boolean>,
+
+	SelectionChanged: ((amISelected: boolean, previousSelection: GuiObject, newSelection: GuiObject) -> ())?,
+}
+
+type UIGridStyleLayoutProps = InstanceProps & {
+	FillDirection: Prop<Enum.FillDirection>,
+	HorizontalAlignment: Prop<Enum.HorizontalAlignment>,
+	SortOrder: Prop<Enum.SortOrder>,
+	VerticalAlignment: Prop<Enum.VerticalAlignment>,
+}
+
+type GuiObjectProps = GuiBase2dProps & {
+	Active: Prop<boolean>,
+	AnchorPoint: Prop<Vector2>,
+	AutomaticSize: Prop<Enum.AutomaticSize>,
+	BackgroundColor3: Prop<Color3>,
+	BackgroundTransparency: Prop<number>,
+	BorderColor3: Prop<Color3>,
+	BorderMode: Prop<Enum.BorderMode>,
+	BorderSizePixel: Prop<number>,
+	ClipsDescendants: Prop<boolean>,
+	Interactable: Prop<boolean>,
+	LayoutOrder: Prop<number>,
+	NextSelectionDown: Prop<GuiObject>,
+	NextSelectionLeft: Prop<GuiObject>,
+	NextSelectionRight: Prop<GuiObject>,
+	NextSelectionUp: Prop<GuiObject>,
+	Position: Prop<UDim2>,
+	Rotation: Prop<number>,
+	Selectable: Prop<boolean>,
+	SelectionImageObject: Prop<GuiObject>,
+	SelectionOrder: Prop<number>,
+	Size: Prop<UDim2>,
+	SizeConstraint: Prop<Enum.SizeConstraint>,
+	Visible: Prop<boolean>,
+	ZIndex: Prop<number>,
+
+	InputBegan: ((input: InputObject) -> ())?,
+	InputChanged: ((input: InputObject) -> ())?,
+	InputEnded: ((input: InputObject) -> ())?,
+	MouseEnter: ((x: number, y: number) -> ())?,
+	MouseLeave: ((x: number, y: number) -> ())?,
+	MouseMoved: ((x: number, y: number) -> ())?,
+	MouseWheelBackward: ((x: number, y: number) -> ())?,
+	MouseWheelForward: ((x: number, y: number) -> ())?,
+	SelectionGained: (() -> ())?,
+	SelectionLost: (() -> ())?,
+	TouchLongPress: ((touchPositions: { Vector2 }, state: Enum.UserInputState) -> ())?,
+	TouchPan: ((
+		touchPositions: { Vector2 },
+		totalTranslation: Vector2,
+		velocity: Vector2,
+		state: Enum.UserInputState
+	) -> ())?,
+	TouchPinch: ((touchPositions: { Vector2 }, scale: number, velocity: number, state: Enum.UserInputState) -> ())?,
+	TouchRotate: ((touchPositions: { Vector2 }, rotation: number, velocity: number, state: Enum.UserInputState) -> ())?,
+	TouchSwipe: ((swipeDirection: Enum.SwipeDirection, numberOfTouches: number) -> ())?,
+	TouchTap: ((touchPositions: { Vector2 }) -> ())?,
+}
+
+type LayerCollectorProps = GuiBase2dProps & {
+	Enabled: Prop<boolean>,
+	ResetOnSpawn: Prop<boolean>,
+	ZIndexBehavior: Prop<Enum.ZIndexBehavior>,
+}
+
+type GuiButtonProps = GuiObjectProps & {
+	AutoButtonColor: Prop<boolean>,
+	Modal: Prop<boolean>,
+	Selected: Prop<boolean>,
+	Style: Prop<Enum.ButtonStyle>,
+
+	Activated: ((input: InputObject, clickCount: number) -> ())?,
+	MouseButton1Click: (() -> ())?,
+	MouseButton1Down: ((x: number, y: number) -> ())?,
+	MouseButton1Up: ((x: number, y: number) -> ())?,
+	MouseButton2Click: (() -> ())?,
+	MouseButton2Down: ((x: number, y: number) -> ())?,
+	MouseButton2Up: ((x: number, y: number) -> ())?,
+}