openapi-typesafe

Type-safe TypeScript for OpenAPI: generate types from an OpenAPI 3.x schema and call your API with a fully typed fetch client.

openapi-typesafe is a maintained, drop-in successor to openapi-typescript and openapi-fetch, whose author stopped maintaining them in September 2026. It is a fork with the full upstream history (see NOTICE).

Release candidate. The current version is a 1.0.0 release candidate (1.0.0-rc.N); names and output can still change before 1.0.0.

Design goals

• Drop-in. Migrate by changing package names. Generated output and the client API stay compatible.
• TypeScript 7 ready. The generator does not use the TypeScript compiler API, so it works the same on TypeScript 5.4, 6 and 7.
• Verifiably compatible. A public compatibility report compares the output with openapi-typescript on more than 1,800 real-world OpenAPI 3.x schemas. CI runs the full corpus every night; the report is refreshed from that run for every release candidate and every major or minor release, and the GitHub release notes link it.
• Secure releases. Minimal dependencies, npm provenance, no long-lived publish tokens.
• Stable API. Semantic versioning from 1.0.0; Versioning lists what a version promises.

Packages

Package	Replaces	Purpose
openapi-typesafe	openapi-typescript	CLI and Node API: OpenAPI 3.0, 3.1 and 3.2 → TypeScript types
openapi-typesafe-fetch	openapi-fetch	Type-safe fetch client for the generated types
openapi-typesafe-helpers	openapi-typescript-helpers	Shared type helpers
openapi-typesafe-react-query	openapi-react-query	TanStack Query bindings
openapi-typesafe-migrate	—	Moves a project to the packages above

All packages share one version (ADR-016).

Usage

npx openapi-typesafe ./openapi.yaml -o ./src/api/schema.d.ts

import createClient from "openapi-typesafe-fetch";
import type { paths } from "./api/schema";

const client = createClient<paths>({ baseUrl: "https://api.example.com/v1/" });

const { data, error } = await client.GET("/posts/{post_id}", {
  params: { path: { post_id: "123" } },
});

Both the request and the response are checked against the schema. There are no manual type annotations.

For coding agents

• Agent skill: skills/openapi-typesafe teaches an agent the setup, typed calls, error handling, middleware, TanStack Query hooks and the migration from openapi-typescript. It follows the Agent Skills format: copy the directory to .claude/skills/ in your project for Claude Code, or to wherever your agent loads skills. tools/skill-evals measures it on 34 coding tasks.
• llms.txt: the docs site serves llms.txt (an index of every page), llms-full.txt (all pages in one file) and a Markdown copy of each page.

Contributing

See CONTRIBUTING.md. Project rules are in GOVERNANCE.md and the Code of Conduct. Report vulnerabilities as described in SECURITY.md.

License

MIT. The original copyright notices of openapi-typescript and openapi-react-query are preserved. This project is not affiliated with or endorsed by the original authors.