openapi-interface-generator

A simple TypeScript utility to generate strongly typed contracts (input, output, and interfaces) based on an OpenAPI YAML specification. This tool helps backend and frontend developers work with consistent request and response types.

Features

• Generate TypeScript interfaces from OpenAPI schemas
• Organize input (request), output (response), and controller interfaces
• Supports nested objects and $ref references
• Fully configurable output paths

---

🛠 Installation

npm install --save-dev openapi-interface-generator

🚀 Usage

Option 1: Add it to your npm scripts

Add this to your package.json:

"scripts": {
    "generate-interfaces": "openapi-interface-generator --openApiPath=./openapi.yaml --generatedDir=./src/app/contracts --interfacesFolder=interfaces --requestsFolder=requests --responsesFolder=responses"
}

Option 2: CLI

openapi-interface-generator  \
  --openApiPath=./openapi.yaml \
  --generatedDir=./src/app/contracts \
  --interfacesFolder=interfaces \
  --requestsFolder=requests \
  --responsesFolder=responses

Running using the npm script

npm run generate-interfaces

⚙ CLI Options

Option	Description	Default
--openApiPath	Path to OpenAPI YAML file	./openapi.yaml
--generatedDir	Base output folder for all contracts	./src/app/contracts
--interfacesFolder	Folder for generated Express interfaces	interfaces
--requestsFolder	Folder for generated request DTOs	requests
--responsesFolder	Folder for generated response DTOs	responses

📂 Output Structure

/contracts
  ├── interfaces
  │   └── tag-name-interface.ts     <-- Controller interfaces
  ├── requests
  │   └── tag-name.request.ts       <-- Input DTOs
  └── responses
      └── tag-name.response.ts      <-- Output DTOs