21st
ActiveUI 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.
Founders
Serafim Korablev· CEO / co-founderOne of the first full-time vibe-coders (since October 2023). Co-founder of 21st.dev, a UI components registry with over 1m users. Previously co-founded Rork.com (then a web app builder for Next.js), the first Telegram-native memecoin launchpad (multi-million exit), and Via, a cross-chain crypto routing protocol with $1.5B GTV backed by Naval, Safe, Sandeep, and others. Passionate about design and basketball.
Sergey Bunas· FounderCS dropout. Senior Software Engineer at Deel (W19). Built Perplexity before Perplexity (Suggesty, 2022 — #1 Product Hunt, featured in Google's internal newsletter). Solo-built a Figma competitor pre-AI (Stage, 10K users). Cambridge AI hackathon winner (solo)
Product launches · 1 launch
The production layer for shipping frontier AI agents inside your product - sandboxing, streaming, billing, UI, and observability out of the box.
Change history · 3 recorded
- July 23, 2026
- Pitch updated07:00 PM
- Description rewritten07:00 PM
- March 16, 2026
- New launch posted: 21st - Infrastructure for AI agents08:16 AM