FleXss

FleXss is a renderer-independent authoring layer for Unity UI. It sits above systems such as uGUI and UI Toolkit so teams can define layouts, styles, themes, tokens, and reusable classes without tying a design system to one renderer.

The first public release centers on the production-tested uGUI implementation. It supports stylesheet-driven workflows, stable Flexbox-style layout, programmatic animation, and editor tools that help teams convert existing prefabs and scenes instead of rebuilding them.

Early versions powered interface animation in Reliquary, while the current system supports the accessible, cross-platform interface behind SkillSaige. FleXss CORE is now entering a limited closed beta focused on real-world integration, layout edge cases, custom components, themes, diagnostics, and documentation.

Read the full introduction or apply for the closed beta.