shadcn/ui is an open-source component library for React that takes a unique approach — instead of installing a package, you copy components directly into your project and own the code. Built on Radix UI primitives and Tailwind CSS, it provides a comprehensive set of accessible, customizable components including data tables, forms, dialogs, charts, and navigation. GTM engineers use it as the foundation for building internal dashboards, CRM interfaces, analytics views, and admin panels. Its copy-paste model means full control over styling and behavior.