Swagger / OpenAPI Generator
Generate a valid OpenAPI 3.0 spec in your browser without writing YAML by hand. Define your API title, version, and server URL, then add endpoints — each with method, path, summary, tags, request body JSON, and response examples. The tool infers request and response schemas from your JSON examples and outputs a complete OpenAPI 3.0.3 spec in YAML or JSON. Download the file and use it with Swagger UI, Postman, Redoc, or any OpenAPI-compatible toolchain. Free, client-side, no signup.
How to Use Swagger / OpenAPI Generator
How to Use the Swagger / OpenAPI Generator
Step 1: Fill in API Info
Enter your API title, version string (e.g. 1.0.0), server base URL, and an optional description. These populate the openapi, info, and servers sections of the spec.
Step 2: Add Endpoints
For each API endpoint:
- Select the HTTP method (GET, POST, PUT, PATCH, DELETE, etc.)
- Enter the path — use curly braces for path parameters (e.g. /users/{id})
- Enter a short summary and optional tags (comma-separated)
- For POST/PUT/PATCH endpoints, paste a JSON example of the request body
- For each response, enter the HTTP status code, a description, and optionally a JSON response body example
The generator infers the JSON Schema automatically from your examples.
Step 3: Add More Endpoints
Click "Add Endpoint" to add more paths. Each endpoint appears as a collapsible row — click the header to expand or collapse it.
Step 4: Choose Output Format
Toggle between YAML and JSON in the output panel. Both are valid OpenAPI 3.0 and work with all major tooling.
Step 5: Download and Use
Click Download to save the spec file (.yaml or .json). Use it with:
- Swagger UI / editor.swagger.io — paste YAML for instant interactive docs
- Postman — Import > File to create a collection from the spec
- Redoc or Stoplight — upload for hosted, styled documentation
- Code generators — use openapi-generator-cli to generate client SDKs
Frequently Asked Questions
Most Viewed Tools
Screen Size Converter
Calculate screen width and height from diagonal size and aspect ratio. Convert between inches and centimeters for displays, TVs, and monitors with instant dimension calculations.
Use Tool →Reorder PDF Pages
Drag and drop to rearrange PDF pages in any order. Upload your PDF, preview all pages as thumbnails, drag pages to reorder them, and download the rearranged PDF. Fast, visual, and privacy-focused.
Use Tool →DPI Calculator
Calculate DPI (dots per inch), image dimensions, and print sizes. Convert between pixels and physical dimensions for printing and displays.
Use Tool →Paper Size Converter
Convert between international paper sizes (A4, Letter, Legal) with dimensions in mm, cm, and inches. Compare ISO A/B series and North American paper standards.
Use Tool →Fuel Consumption Converter
Convert between MPG (miles per gallon), L/100km (liters per 100 kilometers), and other fuel efficiency units. Compare car fuel economy across different measurement systems.
Use Tool →CSV Splitter
Split large CSV files into smaller files by number of rows. Process large datasets in manageable chunks instantly.
Use Tool →Product Schema Generator
Generate JSON-LD Product schema markup for SEO. Add product details like name, price, brand, rating, and availability to create structured data for rich search results.
Use Tool →Large Text File Viewer
View and search large text files up to 200MB in your browser. Features virtual scrolling, line numbers, search functionality, and file statistics. Perfect for log files, CSV, JSON, and code files.
Use Tool →Related Development Tools
QR Code Generator
FeaturedCreate custom QR codes for URLs, text, and contact info
Use Tool →YAML to JSON Converter
Convert YAML data to JSON format instantly. Supports nested objects, arrays, and multi-level structures. Output as pretty-printed or minified JSON. 100% client-side and free.
Use Tool →Parquet to CSV Converter
Convert Apache Parquet files to CSV format instantly in your browser. No uploads, no server — all processing is 100% client-side.
Use Tool →CSS to SCSS Converter
Convert plain CSS to SCSS/Sass instantly. Automatically nests child selectors under their parents, extracts repeated hex colors as $variables, and preserves @media blocks — no server required.
Use Tool →Kotlin Formatter
Format Kotlin code instantly in your browser. Fix indentation, enforce opening-brace-on-same-line style, and add trailing commas to function parameters and class bodies — no server required.
Use Tool →Ruby Formatter
Format and clean up Ruby code instantly in your browser. Fix indentation, align end blocks, and normalize string quotes — no server required.
Use Tool →XML to TOON Converter
Convert XML to TOON (Token Oriented Object Notation) and reduce LLM token usage. XML is the most verbose format — savings can exceed 50%. Free, browser-based.
Use Tool →Rust Formatter
Format Rust code instantly in your browser. Fix indentation, enforce opening-brace-on-same-line style, and add trailing commas to structs and enums — no server required.
Use Tool →Share Your Feedback
Help us improve this tool by sharing your experience