Valibot

Valibot is an open-source schema library for TypeScript designed to validate unknown data with a focus on bundle size, type safety, and developer experience. It allows developers to define schemas that describe structured data sets, similar to TypeScript type definitions, but with the crucial difference that Valibot schemas can be executed at runtime to guarantee the type safety of incoming data. This makes it ideal for scenarios where data originates from external sources and needs rigorous validation. The library's modular design is a core differentiator, enabling significant bundle size reductions through tree shaking and code splitting. This is particularly beneficial for client-side form validation and serverless environments where minimizing payload size is critical. Valibot supports validation for almost any TypeScript type, from primitive values to complex objects, and includes important validation and transformation helpers. It boasts 100% test coverage and offers a minimal, readable, and well-thought-out API to ensure a great developer experience.