Typia is a transformer library that generates super-fast runtime validators and serializers from TypeScript types at build time.
The tool solves the problem of runtime type validation and serialization by analyzing TypeScript type definitions during compilation and generating dedicated, optimized functions rather than relying on runtime reflection or external schemas. When you call a typia function like `typia.is<T>()`, the compiler transforms it into a specialized type checker by examining the target type at the compilation level. This approach eliminates the need to write separate validation schemas or use runtime reflection, allowing developers to leverage TypeScript's static types directly for runtime safety.
Typia suits projects that need high-performance validation, serialization, or deserialization of typed data. It is particularly valuable for applications handling JSON, implementing LLM function calling with structured outputs, working with Protocol Buffer messages, or generating random test data. The tool requires using the `ttsc` toolchain rather than the standard TypeScript compiler, and bundler integration is available through `@ttsc/unplugin` for tools like Vite, Next.js, Webpack, Rollup, and esbuild. The README emphasizes performance gains compared to alternatives like `class-validator` and `class-transformer`, though it does not provide detailed comparisons with other validation libraries.
Maintainers typically respond to new issues and pull requests within a day. Work in the issue tracker is dominated by bug reports, questions, and enhancement requests.
