What is OpenAPI/Swagger?

OpenAPI (formerly Swagger) is a standardized specification for describing REST APIs in YAML or JSON format, defining endpoints, parameters, request bodies, response formats, etc.

Which OpenAPI versions are supported?

Supports OpenAPI 3.0.x/3.1.x and Swagger 2.0. The tool auto-detects the version and adapts parsing.

Are YAML and JSON formats supported?

Yes. The tool auto-detects input format. Also supports drag-and-drop .yaml/.json file import.

Completely safe. All API document parsing and display runs locally in your browser. No data is uploaded.

How do I view endpoint details?

Click an endpoint card to expand details showing parameters, request body, response formats, and more.

Can I search endpoints?

Yes. Type a path or method name in the search box to filter matching endpoints in real-time.

Is file drag-and-drop supported?

Yes. Drag a .yaml or .json file onto the editor area to auto-parse and display the API document.

Free OpenAPI/Swagger Viewer - Visual API Doc Parser

What Can the OpenAPI/Swagger Viewer Do?

The OpenAPI/Swagger Viewer is a free online developer tool for parsing and visualizing OpenAPI (Swagger) specification API documents. Supports both YAML and JSON formats, auto-detects OpenAPI 3.x and Swagger 2.0 versions. After parsing, it displays API info, endpoint list, request parameters, response formats, and data models in intuitive card format — no software installation needed.

Core Features

Multi-Format Support: Auto-detects YAML and JSON formats, supports OpenAPI 3.0/3.1 and Swagger 2.0
Endpoint Visualization: Displays all API endpoints grouped by path, with HTTP method, summary, and parameters
Parameter Details: Expand endpoints to see full parameter list including name, type, location, required status, and description
Response Display: Shows response status codes and response models for each endpoint
Data Models: Lists all Schema definitions with property names, types, and descriptions
Search & Filter: Real-time search by endpoint path and method to quickly locate target APIs

How to Use

1. Paste OpenAPI/Swagger document content in the text box, or drag a .yaml/.json file to import.

2. Click "Parse" to auto-detect format and version, then parse the API document.

3. View document title, version, and description in the API info section.

4. Browse all API endpoints in the endpoint list. Click to expand and see parameter and response details.

5. Use the search box to quickly filter endpoints. Ctrl+Enter to parse, Ctrl+Shift+C to copy results.

Use Cases

Case 1: API Documentation Review

Developers quickly browse API docs before integrating third-party APIs, understanding available endpoints and parameter requirements without installing Swagger UI.

Case 2: Team Collaboration

Backend teams share OpenAPI docs with frontend teams. Frontend developers view interface definitions intuitively, reducing communication costs.

Case 3: API Design Review

Architects review API designs by quickly checking endpoint naming, parameter definitions, and response format compliance.

Case 4: Learning Reference

Students and beginners learn REST API design best practices by parsing public API docs like GitHub API or Petstore example.

Extended Knowledge

The OpenAPI Specification (OAS) is maintained by the OpenAPI Initiative under the Linux Foundation, with the latest version being 3.1.0. Swagger was the predecessor to OpenAPI, renamed after version 2.0. OpenAPI documents describe API endpoints (paths), operations, parameters, request bodies, responses, and security schemes. YAML format is more popular for readability, while JSON is better for programmatic processing. The complete OpenAPI ecosystem includes code generators (OpenAPI Generator), documentation renderers (Swagger UI/Redoc), and testing tools (Postman).

📖 OpenAPI/Swagger Viewer

📂 Import API Document

🔗 API Endpoints

📦 Data Models

📤 Export