21st.dev — AI Agent Registry, UI Components & Developer Tools for the Agentic Internet
21st.devShip AI-powered products faster with 21st.dev. Browse the open AI agent registry, discover ready-to-use agent configs for Claude Managed Agents, copy React UI components, and build with the Agents SDK.
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Visit sitePros
- +Ready-to-use AI agent configs and React UI components for fast shipping
- +Built-in chat history, spend limits, sandbox execution, and observability
- +Works with both Claude and OpenAI; supports token streaming via SSE
- +Open agent registry with reusable templates reduces boilerplate setup
Cons
- −Primarily focused on AI/agent use cases; limited general-purpose UI coverage
- −Requires familiarity with Claude Managed Agents or OpenAI APIs to fully utilize
About this tool
AI-generated21st.dev is a developer platform offering an open AI agent registry, reusable React UI components, and an Agents SDK for building AI-powered products. It includes built-in features like sandboxed execution, chat history, spend limits, and observability. The platform supports both Claude and OpenAI, targeting developers building agentic web applications.
Rating★★★★★(5/5)