What is Radix UI?
An unstyled, accessible React component primitive library. Used as the foundation under shadcn/ui and most modern React component systems.
Radix UI provides unstyled, accessible React primitives — dialogs, dropdowns, popovers, tooltips, accordions, tabs — that handle the hard parts (focus traps, keyboard navigation, ARIA attributes, escape-key handling, click-outside detection) without imposing any visual design. You bring the styling (typically Tailwind CSS) and Radix handles correctness. This is the right separation of concerns: accessibility is hard and bespoke; visual design should be yours. shadcn/ui combines Radix primitives with Tailwind classes and ships the assembled components for copy-paste — but you can use Radix directly without shadcn. Radix is maintained by the WorkOS team (formerly Modulz) and has become the de facto primitive layer for React UI in 2026, displacing earlier alternatives like Reach UI.