Radix UI is an open-source component library that provides low-level, unstyled UI primitives for building modern web applications and design systems. It is designed primarily for React and focuses on accessibility, composability, and developer experience.

Unlike traditional UI libraries that include predefined styles, Radix UI follows a “headless” approach. This means it provides the underlying logic, structure, and accessibility features for components—such as dialogs, dropdowns, tooltips, and tabs—while leaving all styling decisions to the developer. This allows teams to fully customize the look and feel of their interfaces without sacrificing usability or accessibility.

Radix UI solves a key challenge in frontend development: implementing accessible components correctly. It handles complex details such as keyboard navigation, focus management, and ARIA attributes out of the box, ensuring compliance with accessibility standards while reducing development effort.

The library is built as a set of composable primitives, meaning each component is modular and can be combined or extended to fit different use cases. Developers can adopt it incrementally, using only the components they need, and integrate it with any styling system such as Tailwind CSS, CSS-in-JS, or custom frameworks.

Radix UI is widely used as a foundation for custom design systems and has influenced other tools and libraries that build on top of its primitives. It is maintained as an open-source project backed by WorkOS and the developer community.

Key features include:

• Unstyled, headless UI primitives for full design flexibility
• Built-in accessibility with WAI-ARIA compliance
• Composable and modular component architecture
• Handles complex behaviors like focus management and keyboard navigation
• Incremental adoption with framework-agnostic styling support

Common use cases include building custom design systems, creating accessible React applications, developing SaaS interfaces, and powering component libraries that require full styling control.

Radix UI was originally created by the team at Modulz and is now maintained by WorkOS as an open-source project.