Zod 4 is a significant update to the popular TypeScript schema validation library, offering enhanced performance, new features, and improved support for modern web applications. This version introduces substantial internal optimizations, resulting in faster parsing, reduced memory usage, and a leaner core bundle, which is beneficial for both server-side and frontend projects. Key features include the lightweight @zod/mini variant for performance-sensitive environments, built-in JSON Schema conversion to simplify workflows, and a Global Registry for managing and reusing schemas across large applications. Enhancements in error handling improve readability, making debugging more straightforward, while native support for file validation streamlines processes for browser-based applications. Zod 4 also addresses previous limitations by introducing a more efficient API, offering developers a powerful tool for building scalable and efficient TypeScript applications.