Head-to-Head Startup Ranking & Discovery
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21st

SaaS · US · Early-stage
21st.dev ↗

21st.dev is the largest React component registry for AI applications, used by 2M developers (370K MAU). We provide the building blocks to create AI agents and agent-powered apps: UI components, agent templates, and an SDK with built-in UI, tools, memory, observability, and managed infrastructure.

Founded
2026
Headquarters
San Francisco, CA, USA
Team size
1–10
Stage
Early-stage
📊 Coliseo ratings
🏆 Overall 1492 Elo
1496
💰 Conviction
Provisional
1477
🔥 Momentum
Provisional
1504
🧲 Talent
Provisional
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Ratings are live Elo scores from head-to-head crowd votes — opinion, not fact or financial advice. How it works →