OpenAPI Validator
Validate OpenAPI 3.x and Swagger 2.0 specs. Catch structural errors, missing fields, and best-practice issues instantly in your browser.
What Is OpenAPI Validator?
OpenAPI Validator checks your OpenAPI 3.x or Swagger 2.0 specification for structural correctness and best-practice compliance. Paste YAML or JSON and instantly see errors, warnings, and improvement suggestions — all processed locally in your browser with no data sent to any server.
How to Use
- Paste your OpenAPI 3.x or Swagger 2.0 YAML / JSON spec into the editor
- Click Validate — issues appear immediately
- Fix errors (red) first, then warnings (yellow), then consider info suggestions (blue)
- A green banner means the spec passes all required checks
Features
- Supports OpenAPI 3.0 / 3.1 and Swagger 2.0
- Validates required fields: info, title, version, paths, responses
- Checks path format, HTTP methods, and operation structure
- Detects missing servers / host definitions
- Highlights schema and security scheme issues
- Completely client-side — your spec never leaves the browser
Frequently Asked Questions
What is the difference between OpenAPI 3.x and Swagger 2.0?
Swagger 2.0 was the original specification by SmartBear. OpenAPI 3.x is its successor under the OpenAPI Initiative, adding features like multiple servers, request body objects, and improved component reuse.
Does this validator support YAML input?
Yes. Paste either YAML or JSON — the validator auto-detects the format. YAML is parsed client-side without any external library.
Does the validator enforce full JSON Schema compliance?
This tool performs structural validation (required fields, correct types, path format, response existence) rather than exhaustive JSON Schema deep-validation. For production CI pipelines, pair it with tools like spectral or swagger-cli.
Is my spec data safe?
Yes — all validation runs entirely in your browser. Your spec is never uploaded or stored anywhere.