OpenAPI → Cloudflare Worker Mock Generator

Convert any OpenAPI 3.x schema into a fully functional Cloudflare Worker mock API in seconds — entirely in your browser.

🚀 Features

• 🌐 100% Client-Side - No server required, runs entirely in your browser
• ⚡ Instant Generation - Paste schema, click generate, deploy
• 🎯 Smart Fallbacks - Multiple mock data generation strategies
• 🔒 Safe Code Output - Properly escaped, production-ready JavaScript
• 🎨 Dark Theme UI - Beautiful, modern interface
• 📦 Zero Dependencies - Pure HTML, CSS, and JavaScript
• 🔧 Extensible - Modular codebase ready for customization

🎯 Use Cases

• Frontend Development - Mock backends before API implementation
• Testing & QA - Reliable, consistent test data
• Demos & Prototypes - Quick API mocking for presentations
• CI/CD Pipelines - Temporary mock endpoints for testing
• API Documentation - Interactive examples with real responses

🛠️ Quick Start

Option 1: Use Online (Recommended)

Simply open index.html in your browser - no installation needed!

Option 2: Local Development

# Clone the repository
git clone https://github.com/yourusername/openapi-worker-generator.git
cd openapi-worker-generator

# Open in browser
open index.html  # macOS
# or
start index.html  # Windows
# or
xdg-open index.html  # Linux

📖 How It Works

1. Paste Schema - Add your OpenAPI 3.x JSON schema
2. Select Fallback Mode - Choose how to generate mock data
3. Generate - Click the button to create your worker
4. Deploy - Copy or download worker.js and wrangler.toml

Deployment

# Install Wrangler (Cloudflare's CLI)
npm install -g wrangler

# Login to Cloudflare
wrangler login

# Deploy your worker
wrangler deploy

🎨 Fallback Modes

The generator uses a smart example precedence system:

Example Priority (Highest to Lowest)

1. Named examples: responses[status].content[type].examples[name].value
2. Inline example: responses[status].content[type].example
3. Schema example: responses[status].content[type].schema.example
4. Selected fallback mode (see below)

Fallback Strategies

1. Basic Stub (Default)

{
  "ok": true,
  "mocked": true,
  "path": "/users"
}

Simple, reliable response when no schema is available.

2. Schema-Typed Stub

{
  "id": 0,
  "name": "string",
  "email": "user@example.com",
  "active": false
}

Generates typed mock data based on your schema definitions.

3. JSON-Schema-Faker Pre-generation

{
  "id": 847,
  "name": "xkpqwmfhzt",
  "email": "user529@example.com",
  "active": true
}

Creates realistic, randomized mock data with variety.

📋 Example OpenAPI Schema

{
  "openapi": "3.0.0",
  "info": {
    "title": "Users API",
    "version": "1.0.0"
  },
  "paths": {
    "/users": {
      "get": {
        "summary": "List all users",
        "responses": {
          "200": {
            "description": "Success",
            "content": {
              "application/json": {
                "example": [
                  { "id": 1, "name": "Alice" },
                  { "id": 2, "name": "Bob" }
                ]
              }
            }
          }
        }
      }
    },
    "/users/{id}": {
      "get": {
        "summary": "Get user by ID",
        "parameters": [
          {
            "name": "id",
            "in": "path",
            "required": true,
            "schema": { "type": "integer" }
          }
        ],
        "responses": {
          "200": {
            "description": "Success",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "properties": {
                    "id": { "type": "integer" },
                    "name": { "type": "string" },
                    "email": { "type": "string", "format": "email" }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}

🔧 Generated Worker Features

The generated Cloudflare Worker includes:

• ✅ Regex-based routing - Fast path matching with parameter support
• ✅ CORS headers - Pre-configured for cross-origin requests
• ✅ OPTIONS handling - Automatic preflight request support
• ✅ Content negotiation - Respects Content-Type from schema
• ✅ Status codes - Uses correct HTTP status from your spec
• ✅ 404 handling - Graceful fallback for unmatched routes
• ✅ No runtime dependencies - Pure JavaScript, no external libs

🏗️ Architecture

openapi-worker-generator/
├── index.html          # Main UI structure
├── style.css           # Dark theme styling
├── app.js              # Core generator logic
│   ├── Utilities       # Escaping, regex, type generation
│   ├── Parser          # OpenAPI schema parsing
│   ├── Generator       # Worker code generation
│   └── UI              # Event handlers, display
└── README.md           # This file

🎯 Supported OpenAPI Features

Feature	Supported	Notes
OpenAPI 3.0.x	✅	Full support
OpenAPI 3.1.x	✅	Full support
Path parameters	✅	{id} converted to regex
Query parameters	⚠️	Ignored (mocks don't validate)
Request bodies	⚠️	Ignored (mocks return examples)
Multiple responses	✅	Uses first 2xx or first available
Examples	✅	Named, inline, and schema examples
Content types	✅	Respects Content-Type header
Security	⚠️	Not validated (future feature)
Callbacks	❌	Not supported
Links	❌	Not supported

🔮 Roadmap

Future enhancements planned:

• Authentication mocking - Basic/Bearer token validation
• Delay simulation - x-mock-delay extension support
• Query param overrides - ?__status=404&__example=error
• TypeScript output - Optional TS worker generation
• Multiple workers - Split by tag/path prefix
• Request logging - Optional console/analytics integration
• State simulation - POST/PUT/DELETE state tracking
• Webhook forwarding - Proxy real requests to external URLs

🤝 Contributing

Contributions are welcome! The codebase is designed to be modular and extensible.

📄 License

MIT License - see LICENSE file for details.

🙏 Acknowledgments

• Inspired by the need for instant API mocking during frontend development
• Built for developers who need reliable mock APIs without complex setup
• Designed with Cloudflare Workers' simplicity and performance in mind