React design system
Provides an open-source system of components and design tokens for React products.
Coding / product dossier
Once UI 2.0
Provides React components, design tokens and task guides for developers and coding agents.
Product brief
What Once UI 2.0 does.
Once UI is an open-source design system for building polished React products with less repetitive code. Compose layouts with readable primitives, use a shared system of components and design tokens, and keep the result consistent as your product grows. Version 2.0 gives both you and your coding agent a clearer way to work. Its component catalog, compact rules, and task guides help agents use the system correctly; its foundations and predictable APIs make the output easier for you to understand.
Why we selected it
An open-source React design system with component rules and task guides intended to help coding agents produce consistent interfaces.
- Best for
- Design systems
- Category
- Coding
- Daily picks
- 1
- First selected
- 2026-09-27
Product preview saved with our daily selection
Capability scan
What it can help with.
Only capabilities supported by the product information we collected are listed here.
Composable layouts
Uses readable primitives to compose layouts.
Agent-facing guidance
Includes a component catalog, compact rules and task guides to help coding agents use the system.
Consistent foundations
Provides foundations and predictable APIs intended to make resulting interfaces easier for developers to understand.
Best-fit use cases
Build a React interface using shared components and design tokens.
Give a coding agent component rules and task guides while it works on a React UI.
Compose product layouts from the design system's primitives.
FAQ
Before you open it.
What is Once UI 2.0?
It is an open-source design system for building React products.
What does it provide for coding agents?
It provides a component catalog, compact rules and task guides to help agents use the design system.
How can developers compose layouts?
The system includes readable layout primitives alongside shared components and design tokens.