SlaterUI

slater /ˈsleɪ.tər/ noun. In Unreal Engine, something that lays out Slate for you, from a text file, while the game is running.

A text-first, declarative UI layer for Unreal Engine. Describe a screen in a small HTML-like file, get real native Slate widgets, and watch it update the instant you save. No recompile, no Blueprint graph, no opaque .uasset.

View on GitHub

Experimental. The syntax and API are still moving. MIT licensed.

A taste

Panel.sltr

<surface role="UI.Surface.Panel" inset="UI.Space.L" width="360">
  <vbox>
    <text font="UI.Font.Heading" margin="UI.Space.S">Inventory</text>
    <text wrap="true" margin="UI.Space.S">Drag an item onto a slot to equip it. Right-click an item to split the stack.</text>
    <text font="UI.Font.Caption" color="UI.Color.TextMuted" margin="UI.Space.S">12 of 40 slots used</text>
    <hbox margin="UI.Space.M" halign="right">
      <surface role="UI.Surface.Button" inset="UI.Space.M" margin="UI.Space.S">
        <text color="#FFFFFF">Sort</text>
      </surface>
      <surface role="UI.Surface.Panel" inset="UI.Space.M" margin="UI.Space.S">
        <text>Close</text>
      </surface>
    </hbox>
  </vbox>
</surface>

Colors, fonts, spacing and surfaces are tokens from a separate style file. Swap the style and the same layout is re-themed, with no change to the layout.

The Panel layout rendered in the Base style — Base style

The same Panel layout rendered in the Dusk style — Dusk style

Why SlaterUI?

Fast iteration. Layouts and styles reload live. A broken edit keeps the last good UI on screen and shows the error with file, line and column.
Text you can diff and merge. A UI change is a few lines in a pull request, not a binary blob.
Easy for humans and agents. A small, strict syntax with helpful error messages.
Native Slate underneath. No separate renderer, small overhead, and an exit ramp to plain Slate if you need one.