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Hey API review

Free#17 of 25 in API Generation Software

A free, open-source generator for TypeScript and Python API clients and models.

7.0/10Editor score
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Hey API7.0 Visit Hey API

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Hey API is an open-source API code-generation toolkit for developers and engineering teams working from OpenAPI specifications. Its openapi-ts generator accepts local paths, URLs, API registries, inline objects, and OpenAPI specification objects, then produces TypeScript clients, SDKs, typed models, schemas, and related integrations. A separate Python generator produces SDKs and Pydantic models, making the toolkit relevant to teams standardizing generated API code across those two languages.

The core toolkit is free and includes a free plan. Deployment options cover cloud and self-hosted use, while the documented Hey API Registry sits alongside the locally runnable generator. Its ecosystem fit is broad for TypeScript projects: plugins support Fetch API, Angular, Axios, Ky, Next.js, Nuxt, OFetch, Zod, Valibot, TanStack Query, Fastify, Nest, oRPC, MSW, and Playwright. Vite build-pipeline integration and watch mode can keep generated output aligned with changing remote specifications.

Hey API’s main strength is the depth of its composable plugin model. Teams can generate SDK clients, typed models, validation schemas, TanStack Query hooks, testing assets, and framework-specific outputs rather than adopting a single fixed client format. The trade-off is focus: language generation is centered on TypeScript and Python, and projects need to choose and configure the plugins that match their stack. Support is provided through documentation and community channels. Choose Hey API when OpenAPI-driven TypeScript generation, self-hosting, and integration breadth matter; consider another tool if you need generated clients for languages beyond its documented generators or a different support model.

Hey API pros and cons

  • Where it wins
    • Composable plugins cover SDKs, models, schemas, validators, hooks, and testing.
    • Accepts OpenAPI inputs from paths, URLs, registries, inline objects, or spec objects.
    • Supports Fetch, Axios, Angular, Next.js, Nuxt, Zod, Valibot, and TanStack Query.
  • Where it doesn't
    • Generated language coverage centers on TypeScript and Python.
    • Support channels are limited to documentation and community resources.
    • Plugin-based generation requires selecting outputs for each project’s needs.

Hey API fact sheet, pricing and score →

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