Roblox UI

Foundations

• Put UI in StarterGui as ScreenGuis (copied to each player's PlayerGui), or create it from a client controller. UI code is client-only; the server never touches PlayerGui in normal designs.
• ScreenGui defaults to set: ResetOnSpawn = false (keep UI across deaths), ZIndexBehavior = Sibling, IgnoreGuiInset per design, ScreenInsets = CoreUISafeInsets for interactive UI (clears notches and the Roblox top bar); DeviceSafeInsets/None only for full-bleed backgrounds.
• Size and position with Scale (UDim2.fromScale) plus constraints; use Offset only for fixed details (padding, strokes, icons). Pure-Offset UI breaks on phones and 4K screens.
• AnchorPoint = Vector2.new(0.5, 0.5) + Position = UDim2.fromScale(0.5, 0.5) centers an element.
• UIAspectRatioConstraint keeps shapes square/consistent; UISizeConstraint caps sizes; UITextSizeConstraint with TextScaled bounds text size (prefer fixed TextSize + AutomaticSize where possible — TextScaled produces inconsistent sizes).
• AutomaticSize lets frames grow with content (lists, tooltips, chat bubbles).
• Test every screen in the Device Emulator (phone portrait/landscape, tablet, console 10-foot, 4K).

Layout