openapi-typescript turns OpenAPI 3.0 & 3.1 schemas into TypeScript quickly using Node.js. No Java/node-gyp/running OpenAPI servers necessary.

The code is MIT-licensed and free for use.

Features

• ✅ Supports OpenAPI 3.0 and 3.1 (including advanced features like discriminators
• ✅ Generate runtime-free types that outperform old school codegen
• ✅ Load schemas from YAML or JSON, locally or remotely
• ✅ Generate types for even huge schemas within milliseconds

Note: OpenAPI 2.x is supported with versions 5.x and previous

Examples

👀 See examples

Setup

This library requires the latest version of Node.js installed (20.x or higher recommended). With that present, run the following in your project:

npm i -D openapi-typescript

Highly recommended

Enable noUncheckedIndexedAccess in your tsconfig.json (docs)

Basic usage

First, generate a local type file by running npx openapi-typescript:

# Local schema
npx openapi-typescript ./path/to/my/schema.yaml -o ./path/to/my/schema.d.ts
# 🚀 ./path/to/my/schema.yaml -> ./path/to/my/schema.d.ts [7ms]

# Remote schema
npx openapi-typescript https://myapi.dev/api/v1/openapi.yaml -o ./path/to/my/schema.d.ts
# 🚀 https://myapi.dev/api/v1/openapi.yaml -> ./path/to/my/schema.d.ts [250ms]

WARNING

Be sure to validate your schemas! openapi-typescript will err on invalid schemas.

Then, import schemas from the generated file like so:

import type { paths, components } from "./api/v1"; // generated by openapi-typescript

// Schema Obj
type MyType = components["schemas"]["MyType"];

// Path params
type EndpointParams = paths["/my/endpoint"]["parameters"];

// Response obj
type SuccessResponse =
  paths["/my/endpoint"]["get"]["responses"][200]["content"]["application/json"]["schema"];
type ErrorResponse =
  paths["/my/endpoint"]["get"]["responses"][500]["content"]["application/json"]["schema"];

From here, you can use these types for any of the following (but not limited to):

• Using an OpenAPI-supported fetch client (like openapi-fetch)
• Asserting types for other API requestBodies and responses
• Building core business logic based on API types
• Validating mock test data is up-to-date with the current schema
• Packaging API types into any npm packages you publish (such as client SDKs, etc.)