21st.dev is a UI interface catalog and registry built by a community of design engineers, positioned as a "living interface library." It offers over 12,000 handcrafted React components, complete templates, shadcn themes, shaders, interactions, and gradients, contributed by more than 700 design engineers. The platform has been used by 4,150,992 builders, ranging from indie developers to large global product teams.
Key Capabilities
- Massive UI resources: 12,000+ handcrafted React components, templates, and shadcn themes, built by real design engineers.
- AI-ready prompts: Every component is provided as a prompt, and one copy lets it be automatically built in any AI tool. Paste it into a terminal and the source code enters your repository; paste it as a task into Codex to generate a diff patch; paste it into a chat window and the exact UI appears in your project.
- Live previews: All components support live online previews.
- One-click installation: shadcn CLI installation commands are provided for the classic installation method.
- Source code ownership: Components use React + Tailwind and shadcn/ui conventions, land in your repository as source code, and are assets you can edit.
- Favorites and lists: Any component can be saved to personal or team-shared lists and retrieved with one click.
- Author system: Every component has an author and is indexable and searchable. Anyone can publish components, retaining author attribution displayed on a public profile page; template authors can sell their work directly.
How to Use
Browse the registry and preview components live; click "Copy prompt" on any component and paste it into Cursor, Claude Code, v0, Lovable, or another AI agent, and the agent will rebuild the component within your codebase and integrate it into your stack. You can also use the included shadcn CLI installation commands. Components are published in the shadcn registry format and are designed to be composed with shadcn/ui primitives and existing design tokens.
Use Cases
Suitable for developers who need to quickly integrate React + Tailwind components into projects, teams using AI agents to generate UI, and builders looking for production-ready templates. Templates are complete production-grade starting points, containing full pages or multi-page applications rather than a single component, and what is included is clearly listed before purchase.
Limitations and Costs
Browsing the entire registry is free, with 2 free component copies per day. Membership unlocks unlimited copies and premium templates from authors. 21st AI is used to generate and optimize UI and is an add-on that requires enabling a monthly credit quota. The difference between a component library and a registry is: a component library is a single package, a single aesthetic, installed as a dependency; 21st is a registry, multi-author, multi-style, where code is copied into your repository rather than imported, is yours to modify, and has no version to upgrade.
