StartupAI & models
21st
UI building blocks for the agentic internet
About
21st.dev is the largest React component registry for AI applications, used by 2M developers We provide the building blocks to create agent-powered apps: UI components, agent templates.
Facts
- Website
- 21st.dev
- City
- San Francisco
- Country
- United States
- YC batch
- Winter 2026
- Team
- 3 people
- Stage
- Early stage
- AI-native
- Yes
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