# openapi-typesafe — type-safe OpenAPI clients, ready for TypeScript 7

A maintained, drop-in successor to openapi-typescript and openapi-fetch, whose author stopped maintaining them in September 2026. It generates TypeScript types from an OpenAPI 3.0, 3.1 or 3.2 schema and gives you a fully typed fetch client. The generator no longer uses the TypeScript compiler API, so it works on TypeScript 5, 6 and 7. Every release is checked against 1,820 real-world schemas: 50,960 cases, 0 unexpected differences.

- **Author:** Fedor Chishchin
- **Role:** Maintainer — fork, generator rewrite, compatibility testing, release pipeline
- **Period:** Nov 2026 — present
- **Stack:** TypeScript · Node.js · OpenAPI 3.x · Vitest · GitHub Actions · npm provenance · VitePress
- **Source:** https://fedorthinks.com/work/openapi-typesafe

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<PackageBadges npm="openapi-typesafe" />

Generate the types, then call your API with a typed client:

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

## Why it exists

[openapi-typescript](https://github.com/openapi-ts/openapi-typescript) and `openapi-fetch` are
how a lot of TypeScript teams talk to their APIs: you point them at an OpenAPI schema and get types
for every path, parameter and response. In September 2026 their author
[stopped maintaining them](https://github.com/openapi-ts/openapi-typescript/issues/2874).

At the same time TypeScript 7 arrived. It is the native port of the compiler, and its `typescript`
package has no JavaScript API: no `ts.factory`, no printer. openapi-typescript builds every type
with `ts.factory`, so in a project on TypeScript 7 it either refuses to install or crashes the
moment it loads.

So thousands of projects had a dependency that was both unmaintained and about to break.

## What I did

I forked it with the full upstream history and set one rule: **migrating must be a package rename,
nothing more.** The same CLI flags, the same Node API, the same generated output, the same client.

- **A generator without the compiler API.** Types are built as a small tree of our own and printed
  by our own printer. It needs no `typescript` package at all, so it runs next to TypeScript 5, 6
  or 7.
- **OpenAPI 3.2 support**, which the original rejects.
- **A migration tool** (`openapi-typesafe-migrate`) that moves a project over: imports, scripts and
  package settings.
- **TanStack Query bindings** and shared type helpers, as drop-in replacements too.

## How I know it's compatible

"Drop-in" is a promise, so it has to be measured, not claimed. A public
[compatibility report](https://openapi-typesafe.github.io/openapi-typesafe/compatibility) compares
our output with openapi-typescript 7.13 on **1,820 real OpenAPI documents**: the whole APIs.guru
directory plus the big ones like GitHub, Stripe, OpenAI, Cloudflare and Kubernetes. Each schema
runs with 28 option sets, so **50,960 cases**.

Every case is checked in three steps: same bytes, then the same types (a strict identity check),
then whether it compiles. The last run: **99.87% byte-for-byte identical, 100% identical types,
0 unexpected differences**. CI runs the full corpus every night, and every release links its
report.

## Secure releases

A code generator runs on your machine and writes code into your project, so its supply chain
matters:

- minimal dependencies;
- npm provenance and no long-lived publish tokens;
- a threat model, a security policy with response times, and private vulnerability reporting;
- OpenSSF Scorecard and OpenSSF Best Practices badges.

## Built for coding agents

The repo ships an **agent skill** that teaches Claude Code (or any agent that reads skills) how to
set up the client, make typed calls, handle errors, and migrate from openapi-typescript. A separate
eval suite measures that skill on 34 coding tasks. The docs site serves `llms.txt`,
`llms-full.txt` and a Markdown copy of every page.

I built it with agentic engineering: coding agents write the code, and I own the design, the
compatibility rule and the proof that it holds.

## Status

Release candidate: `1.0.0-rc.4` on npm. Names and output may still change before 1.0.0, then it
follows semantic versioning. MIT license.