openapi-typescript
Generate TypeScript types from OpenAPI 3.x specs with zero runtime overhead. Unlike openapi-generator (which generates a full SDK), openapi-typescript generates only TypeScript type definitions — no HTTP client code. Use with openapi-fetch (companion package) for a type-safe fetch wrapper, or use generated types manually. Supports OpenAPI 3.0, 3.1, and AsyncAPI schemas. Extremely fast generation via native TypeScript.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Local code generation — no security concerns. Generated types improve security by catching API contract violations at compile time.
⚡ Reliability
Best When
You want compile-time TypeScript types from your OpenAPI spec without a generated HTTP client — lightweight type safety with your own HTTP library.
Avoid When
You need a complete generated SDK with built-in HTTP client, auth, and retry logic — use openapi-generator instead.
Use Cases
- • Generate TypeScript types from OpenAPI specs for type-safe API clients without runtime SDK overhead
- • Keep TypeScript type definitions in sync with API specs automatically in CI — regenerate types on spec changes
- • Build type-safe API clients using openapi-fetch companion package that validates request/response types against OpenAPI spec
- • Type-check API response handling in TypeScript agent code against the OpenAPI contract
- • Generate types for internal microservice APIs to ensure consumers use correct request/response shapes
Not For
- • Full SDK generation with built-in HTTP client — use openapi-generator for multi-language SDK generation with retry logic, auth, etc.
- • OpenAPI 2.0 (Swagger) specs — openapi-typescript focuses on OpenAPI 3.x
- • Runtime request validation — generated types are compile-time only; use zod-openapi or ajv for runtime validation
Interface
Authentication
No authentication — local code generation tool.
Pricing
MIT-licensed open source tool.
Agent Metadata
Known Gotchas
- ⚠ openapi-typescript v6 output format changed significantly from v5 — generated types use different patterns; regenerate and update consuming code after major version upgrade
- ⚠ Generated types reference each other by path schema keys — using the types requires understanding the generated schema structure ($defs, paths, components)
- ⚠ Circular schema references in OpenAPI specs produce TypeScript recursive types — may cause slow TypeScript compilation for very deep circular schemas
- ⚠ openapi-fetch companion package is required for the full type-safe client experience — without it, generated types are useful but require manual wiring
- ⚠ Remote spec URLs require internet access at generation time — cache local copies for offline CI builds
- ⚠ Discriminated union schemas in OpenAPI (oneOf with discriminator) may not produce ideal TypeScript union types — manual type narrowing may be needed
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for openapi-typescript.
Scores are editorial opinions as of 2026-03-06.