21st.dev is a component registry and AI agent deployment platform that has grown to serve 1.4 million developers with 200,000 monthly active users. The platform provides a curated collection of React UI components built on Tailwind CSS and Radix primitives, designed for rapid prototyping and production use in AI-powered applications. Beyond components, 21st.dev offers agent templates and an SDK that simplifies the process of building, testing, and deploying AI agents across different infrastructure providers.
The open-source 1code project serves as the orchestration layer for coding agent workflows, providing a Cursor-like graphical interface for interacting with Claude Code, OpenAI Codex, and other coding agents. It supports multi-agent coordination where multiple AI assistants can work on different parts of a codebase simultaneously, with Git integration for tracking and merging their changes. The visual interface makes agent-assisted development accessible to developers who prefer graphical tools over purely terminal-based workflows.
Backed by Y Combinator, 21st.dev has built significant distribution in the developer tools space through its Magic MCP integration and growing component marketplace. The platform bridges the gap between UI component libraries and agent infrastructure, recognizing that modern AI applications need both polished interfaces and robust agent capabilities. For teams building AI-powered products, it provides a unified platform for sourcing UI components, configuring agent behaviors, and deploying the resulting applications.
