OpenAPI / Swagger Viewer
Free online OpenAPI 3.x viewer. Paste YAML or JSON to visualize API endpoints, parameters, responses, and schemas. No sign-up required.
What Is OpenAPI / Swagger?
OpenAPI (formerly Swagger) is the industry-standard specification for describing RESTful APIs. An OpenAPI document defines your API endpoints, request and response formats, authentication methods, and data schemas in a machine-readable YAML or JSON file. It is widely used for API documentation, client SDK generation, and automated testing.
How to Use This OpenAPI Viewer
- Paste your OpenAPI 3.x specification in YAML or JSON format into the text area.
- The tool automatically parses and displays API info, endpoints, and schemas.
- Click any endpoint to expand details including parameters, request body, and response codes.
- Use the filter bar to search endpoints by path, method, summary, or tag.
- Click a schema name to view its properties and required fields.
Common Use Cases
- Quick API Documentation Review — Visualize an API spec without running a full Swagger UI server.
- Schema Validation — Check that your data models and endpoint definitions are correct before generating client code.
- API Design Collaboration — Share and review API designs by pasting specs during code reviews or planning meetings.
FAQ
Does this support OpenAPI 2.0 (Swagger)?
This viewer is optimized for OpenAPI 3.x. Swagger 2.0 specs may partially work but some fields like consumes/produces are not rendered.
Is my API spec sent to any server?
No. All parsing and rendering happens entirely in your browser. No data leaves your machine.
Can I import from a URL?
Currently you need to paste the spec content directly. Copy the raw YAML/JSON from your file or URL and paste it here.