Overview
21st.dev is a community platform for AI UI components and agent templates, backed by Y Combinator.\n\n## Features\n- UI Components: Curated collection of AI-powered UI components (prompt boxes, AI chat interfaces, animated inputs)\n- Agent Templates: Ready-to-use AI agent templates for web scraping, API design, customer support, data analysis, lead research, and more\n- Agents SDK: Build agents with built-in UI, chat history, spend limits, E2B sandbox execution, and observability\n- MCP Support: Connect to Model Context Protocol servers\n- Private Registry: Host your own component library\n\n## Popular Agent Templates\n- Web Scraper Agent\n- Support Agent (Notion/Slack)\n- Data Analyst (Amplitude)\n- Deep Researcher\n- GitHub Agent\n- Lead Research Agent\n\nBuilt-in SDK features: E2B Sandboxes, token streaming, auth & rate limits, session replay & traces.
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