The TypeScript OpenAPI space is crowded and mature. hey-api, orval, kubb, and openapi-fetch are all good tools, actively maintained, and in some areas more featureful than this one. If you want the broadest plugin ecosystem, mocks, or hooks for every framework, one of them is probably the better pick, and that is fine.
This page exists so you can decide quickly and fairly. It is kept deliberately honest: where the alternatives are ahead, that is stated plainly. A comparison that only flatters itself is not worth reading.
Most generators treat your generated code as disposable: every run overwrites everything, so the
output is a black box you are not meant to touch. openapi-zod-ts is built around the opposite idea.
The Zod schema file is bootstrapped once and then yours forever, the client uses native fetch
with no runtime library, and the whole thing is 1.0 and deliberately small rather than a moving
target. You trade breadth for ownership and stability.
openapi-zod-ts | hey-api | orval | kubb | openapi-fetch | |
|---|---|---|---|---|---|
| TypeScript types | Yes | Yes | Yes | Yes | Yes |
| Fetch client | Yes | Yes | Yes | Yes | Yes (is the client) |
| Runtime library added to your app | None (native fetch) | None (client bundled) | Mutator, often axios | Client of choice | ~6 kb required |
| Zod schemas generated | Yes (opt-in) | Yes (plugin) | Yes | Yes | No |
| Runtime request + response validation | Yes | Yes (Zod plugin) | Yes (Zod) | Yes (Zod) | No |
| Schema file you own, never overwritten | Yes | No | No | No | n/a |
| React Query / TanStack hooks | Yes (React) | Yes (multi) | Yes (multi) | Yes (React, Vue, SWR) | Companion pkg |
| Hooks for Vue / Svelte / Angular / Solid | No | Yes | Yes | Vue | Via ecosystem |
| Server-side service interface + router | Yes (Hono, Express, Fastify) | No | No | No | No |
| Mocks (MSW / faker) | No | Yes (plugin) | Yes | Yes | No |
| OpenAPI 3.1 | Yes | Yes | Yes | Yes | Yes |
| Swagger 2.0 | No | No | Yes | Yes | No |
| Stable 1.0 with semver | Yes | No (0.x) | Yes | Yes | Yes |
You own the Zod schemas
With input_schema enabled, schemas.ts is written once and then never touched again. Add
refinements, custom error messages, and business rules. Re-running the generator overwrites the
client and types but leaves your schemas alone. Every other tool here regenerates schemas on every
run, so hand edits do not survive.
Full-stack from one spec
The only tool in this set that also generates the server side: a framework-agnostic service interface plus an optional router for Hono, Express, or Fastify. One spec drives the client, the hooks, and the server contract, validated at both ends.
Nothing in your bundle
The generated client uses only native fetch. The generator is a devDependency. openapi-fetch
ships a small runtime library you import; orval and kubb generate code that calls a client you
install. Here, nothing the codegen produces lingers in production that your project did not already
have.
Boring on purpose
1.0 and semver-stable, proven on 128 real-world specs in CI with live smoke tests, mutation testing, and published provenance. A code generator has a wide blast radius; for this layer of your stack, predictable beats cutting-edge.
Being honest about this is the point.
Read the migration guide
