zod

Runtime data validation and TypeScript type inference work together by defining a schema that validates incoming data while automatically inferring the resulting static types, ensuring predictable behavior for API requests and config objects.

Validating API request payloads in TypeScript is best handled by defining strict schemas that check runtime data structures and infer types, ensuring type-safe responses and requests without relying on external runtime dependencies.

JSON Schema generation from TypeScript types is supported directly, allowing developers to produce standard JSON Schema outputs from defined validation schemas for broad interoperability across different platforms and services.

Runtime schema validation with zero runtime dependencies is designed for frontend and backend TypeScript projects, featuring a lightweight 2kb gzipped core that ensures minimal footprint while maintaining type safety.

Localized error messages for schema validation are handled through a built-in metadata registry system, allowing developers to customize and internationalize validation error outputs for various user locales.

Runtime validation is necessary alongside TypeScript types because static types only exist during development; runtime validation ensures incoming API data, user inputs, and environment variables actually match expected structures at execution.