typia.io

What It Is

Typia is a developer tool for TypeScript. Its core idea is to take the TypeScript types you have already written and convert them into runtime code at compile time through an AOT transform. This avoids the “duplicate maintenance of types and schemas” commonly seen in solutions such as class-validator, ajv, and zod, and treats TypeScript types as the single source of truth.

Core Capabilities

Functionally, Typia covers runtime validation, Enhanced JSON, LLM Function Calling, Protocol Buffer, and random data generation. Its validation APIs include is, assert, assertGuard, and validate; the JSON features support safe parsing, faster stringification, and OpenAPI/JSON Schema generation. The LLM module can generate tool schemas and parameter schemas from TypeScript classes/types, with parsing, type conversion, and validation feedback included. Protocol Buffer support includes encode/decode and .proto text output. It also supports tag-based constraints such as uuid, email, uint32, minimum, and maximum.

Integration and Documentation

Typia’s main barrier is the build pipeline. The stable production path depends on TypeScript v5/v6, ts-patch, and typia/lib/transform; the experimental path supports TypeScript-Go’s ttsc/ttsx. On the bundler side, @typia/unplugin supports Vite, Next.js, esbuild, Rollup, Rspack, Bun, Webpack, and more. Direct Babel/SWC integration requires generation mode because types are erased too early. The documentation is strong and explicitly covers real-world issues such as CI setups where --ignore-scripts may skip ts-patch install, or Nx potentially swallowing transformer errors.

Pricing and Open Source

The crawled text does not provide commercial pricing, an enterprise plan, or payment methods, nor does it clearly state a license. The page shows GitHub and “Edit this page on GitHub,” but that alone is not enough to infer its open-source license.

Pros, Cons, and Who It’s For

The advantages are zero schema duplication, low runtime overhead, a performance-oriented design, and a unified TypeScript type-driven workflow spanning validation, serialization, Schema, LLM, and Protobuf. The downsides are that adoption is significantly more complex than with pure runtime libraries, and it is sensitive to transformer, ts-patch, bundler plugin, and CI configuration details. It is well suited to TypeScript-heavy backends, API gateways, NestJS/tRPC/Hono projects, and teams that need high-performance validation or automated LLM tool schema generation.

Access from China

The crawled text does not provide information about Mainland China access, mirrors, payment, or compliance, so the access status is rated as unknown. If network or supply-chain constraints are a concern, more traditional options such as zod, ajv, and class-validator may be worth comparing.