21st.dev
The npm for design engineers — discover and share shadcn/ui React components with AI
About 21st.dev
21st.dev is a Y Combinator-backed open-source marketplace for React UI components built on shadcn/ui, Tailwind CSS, and Radix UI. Design engineers can publish, discover, and install production-grade components, blocks, and hooks with a single npx command. Its Magic MCP feature lets AI coding assistants generate and implement UI components directly from natural language prompts.
Pros & Cons
Pros
- Massive library of production-ready shadcn/ui components installable with one command
- Magic MCP integration lets AI assistants generate components from natural language
- Y Combinator-backed with active community and quality review process
- Completely free and open-source with no usage limits
- Components follow shadcn/ui conventions so they integrate seamlessly into existing projects
Cons
- React-only — no support for Vue, Svelte, or other frameworks
- Requires shadcn/ui and Tailwind CSS setup in your project
- Quality varies across community submissions — featured components are curated but not all
- Monetization model unclear which could affect long-term sustainability
- Relatively new platform with evolving feature set
Key Features
Component Marketplace
Browse and install thousands of community-made shadcn/ui React components, blocks, and hooks
One-Command Install
Install any component with a single npx shadcn command — no manual copy-paste needed
Magic MCP for AI IDEs
AI coding assistants like Cursor, Windsurf, and Lovable can generate UI components from natural language prompts
Component Publishing
Publish your own components to the registry with quality review for featured listings
AI Variant Generation
Generate five UI component variants for quick selection and customization
Tailwind + Radix Foundation
All components built on Tailwind CSS and Radix UI primitives for accessibility and consistency
Open Source
Fully open-source platform with transparent community-driven development
Pricing
- Browse all components
- Install via npx shadcn
- Publish components
- AI MCP integration
- Community support
- Open-source access
Best For
Rapid UI Prototyping
Quickly assemble professional interfaces from pre-built components instead of building from scratch
AI-Assisted Frontend Development
Use Magic MCP with Cursor or Windsurf to generate and implement UI components via natural language
Design System Building
Discover and adopt community-tested component patterns as a foundation for your design system
Component Sharing
Publish reusable components for your team or the community with built-in versioning and installation
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