colinhacks/zod

Zod is a TypeScript-first schema validation library that combines runtime validation with static type inference.

Zod solves the problem of validating data at runtime while maintaining type safety in TypeScript. It works by letting you define a schema that describes the shape and constraints of your data, then parse incoming data against that schema. If validation succeeds, you receive a strongly-typed deep clone of the input; if it fails, you get detailed error information. The library includes an ahead-of-time compilation feature that optimizes hot validation paths, achieving median speedups of 2.4x across typical schemas by eliminating per-node dispatch and allocation overhead.

You should choose Zod if you need runtime validation in a TypeScript codebase and want type inference to flow automatically from your schema definitions without maintaining separate type declarations. It suits projects handling API requests, form submissions, or any scenario where external data needs validation before use. The tool works in both Node.js and modern browsers, has zero external dependencies, and maintains a small core bundle size. The library provides built-in JSON Schema conversion and supports an extensive ecosystem of integrations.

Development on the project shows consistent activity with regular test runs and maintenance of the codebase. The maintainer actively engages with the community through Discord and social media channels, indicating ongoing support for users. The project maintains comprehensive documentation and provides multiple communication channels for questions and discussion.