Dev & Engineering runtime-validationjson-schematypescript-transformertype-safe-serializationllm-function-callingprotobufrandom-data-generation

typia: Ultra-Fast Runtime Validators and Serializers via TypeScript Transformation

Leverage TypeScript type transformation to generate zero-dependency, super-fast runtime validators, JSON serializers, LLM function calling harnesses, and Protocol Buffer codecs.

FollowAgents review · FARS-2.1
Not recommended
42/ 100 5-point scale 2.1 / 5
1 2 3 4 5 6
1Trust0 / 29 · 0.0/5

Evidence shows an open-source library with no mechanisms for least privilege, user confirmation, data flow transparency, sensitive data handling, external effects, rollback, or source attribution. Dependency security: package.json lists devDependencies but no lock or security audit. Thus all trust criteria score 0.

2Reliability8 / 14 · 2.9/5

Self-consistency: README and package.json align, feature list clear, score 2. Dependency availability: dependencies managed via pnpm with lock file, but availability not verified, score 2. Failure messages: error handling exists but no detailed failure message documentation, score 1.

3Adaptability12 / 18 · 3.3/5

Audience and scenarios: README lists multiple use cases (validation, JSON, LLM, protobuf), score 2. Capability boundaries: features documented but boundaries not explicit, score 2. Trigger precision: API design clear, score 2. Environment fit: supports multiple bundlers but requires specific toolchain, score 2.

4Convention10 / 18 · 2.8/5

Information architecture: clear documentation structure with guides and API docs, score 2. Install notes: installation steps provided but dependent on specific tools, score 2. Naming stability: consistent API naming, score 2. Examples and FAQ: examples present, FAQ missing, score 2. Known limitations: not explicitly listed, score 1. License: MIT license clear, score 2. Versioning and changelog: version number present, no changelog, score 1. Maintenance responsibility: author and repository present, score 2.

5Effectiveness9 / 13 · 3.5/5

Output usability: outputs are type-safe validators and serializers, score 2. Marginal value: provides unique features, score 2. Cost benefit: performance claims have benchmarks but not verified, score 2.

6Verifiability3 / 8 · 1.9/5

Claim traceability: performance claims have benchmark links but not verified, score 1. Cross-source corroboration: community use cases exist but not independently verified, score 1. Fact-inference separation: documentation distinguishes facts and inferences but not clearly, score 1.

Evidence confidence: Low Reviewed Aug 11, 2026 Reviewed revision e829c27390e9
The upstream repository has new commits since this review. The score still applies to the reviewed revision shown and may not cover the latest changes.
Safety controls not found in source: least-privilege scoping, confirmation before acting, data-flow disclosure, sensitive-data handling, dependency security, disclosed external effects, rollback or recovery path, verifiable attribution
Before you use it
  • This is a static review; code not executed, performance claims unverified.
  • Dependency security not audited; recommend checking for vulnerabilities.
  • Requires specific toolchain (ttsc), may limit environment fit.
Review evidence [1][2][3][4][5][6][7][8]
See the full review method →

What does this agent do, and when should you use it?

typia is a transformer library for TypeScript that generates efficient runtime validators, serializers, and parsers directly from TypeScript types at compile time. It offers validation functions like `is`, `assert`, and `validate`; a `json` namespace for JSON Schema and serialization/parsing; an `llm` namespace for function calling applications and structured outputs; a `protobuf` namespace for Protocol Buffer message encoding/decoding; and a `random` function for generating random data. typia claims its runtime validators are 20,000x faster than class-validator and JSON serialization 200x faster than class-transformer. Developers write plain TypeScript types, and typia generates corresponding runtime code at build time, eliminating the need for additional schemas or runtime reflection.

typia analyzes TypeScript types during compilation and transforms calls like typia.is<T>() into dedicated type-checking code. It reads TypeScript source files, applies transformation via ttsc (a TypeScript compiler wrapper), and outputs optimized JavaScript runtime functions. Specific features include: is<T>() returns a boolean, assert<T>() throws TypeGuardError, validate<T>() returns detailed validation results; json.schema<T>() generates JSON Schema, json.assertParse<T>() and json.assertStringify<T>() provide type-safe parsing and serialization; llm.application<Class>() generates a collection of function calling schemas and validators, llm.structuredOutput<P>() generates structured output schemas, llm.parse<T>() performs lenient JSON parsing; protobuf.message<T>() generates Protocol Buffer message definitions, protobuf.assertDecode<T>() and protobuf.assertEncode<T>() perform safe decoding/encoding; and random<T>() generates random data. The workflow is: install typia and ttsc, build with ttsc, call typia functions in code, and the transformation happens automatically.

  1. TypeScript developers seeking zero-dependency runtime data validation to replace class-validator and similar libraries, with higher performance.
  2. Generating JSON Schema automatically from TypeScript types for API documentation or validation.
  3. Building LLM function calling applications that require accurate function parameter schemas and result parsing.
  4. Using Protocol Buffer for efficient data encoding/decoding while maintaining type safety.
  5. Generating random test data that conforms to TypeScript types during development and testing.
  6. Eliminating the need to manually maintain separate schemas and type definitions by using a single type source to drive all runtime needs.

What are this agent's strengths and limitations?

Pros
  • Extreme performance: runtime validation is 20,000x faster than class-validator and JSON serialization is 200x faster than class-transformer (per README).
  • Pure TypeScript type-driven: no extra schemas or decorators, reducing maintenance overhead.
  • Comprehensive features: validation, JSON, LLM function calling, Protocol Buffer, and random data generation.
  • Type safety guaranteed by compile-time transformation, reducing runtime errors.
Limitations
  • Requires the ttsc toolchain; standard tsc or ts-node do not work, adding build configuration complexity.
  • Integrating with some bundlers requires additional plugins (e.g., @ttsc/unplugin), which may cause compatibility issues.
  • Compile-time transformation may increase build time, especially for large projects.
  • Not all TypeScript types may be supported, requiring workarounds for advanced type constructs.

How do you install or deploy this agent?

Install typia with the ttsc toolchain:

npm i typia
npm i -D ttsc typescript

Note: You must use ttsc instead of tsc, as ttsc applies typia's transform. For bundler integration (Vite, Next.js, etc.), install @ttsc/unplugin.

How do you use this agent?

In a TypeScript file, import typia and use its functions, e.g., import typia from "typia"; const checkString = typia.createIs<string>();. Then build with ttsc: npx ttsc, or run a script directly: npx ttsx src/index.ts. typia generates the corresponding validator code at build time.

How does this agent compare with similar options?

Similar to typescript-is, but typia offers a broader feature set (JSON, LLM, protobuf) and better performance. Other libraries like class-validator require decorators and schemas, with lower performance.

FAQ

Does typia support all TypeScript types?
The README does not list a complete support matrix, but as a transformer it handles most common types; complex types may require additional handling. Check the official documentation or test cases.
What additional build costs do I incur?
You must use the ttsc toolchain instead of standard tsc, which may require adjusting your build process. Bundler integrations need extra plugins.
Does typia have runtime dependencies?
typia generates code at compile time; the runtime footprint is minimal, mainly relying on TypeScript types.
Can typia be integrated into existing projects?
Yes, but you need to adjust the build to use ttsc. Documentation provides integrations for Vite, Next.js, and other bundlers.

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