React is a JavaScript library for building user interfaces, offering the core tools to create UI components and manage state. Next.js is a framework built on top of React that extends its capabilities with features like server-side rendering (SSR), static site generation (SSG), built-in routing, and API routes. While React provides the foundation for building UI, Next.js adds the structure and performance optimizations needed for full production-ready web applications. The choice between React and Next.js depends on your project's needs, with React ideal for interactive single-page applications where SEO isn't a priority, and Next.js exceling in performance, SEO, and scalability for content-heavy sites, e-commerce platforms, and performance-critical apps. Both frameworks integrate seamlessly with Strapi v5, providing flexible, API-driven content management. Mastering both frameworks gives you the flexibility to choose based on project requirements, as React evolves with server components and Next.js expands.