Free toolOpenAPI 3.0 / 3.1

Free Online OpenAPI 3.1 & Swagger Validator

Validate OpenAPI 3.1, 3.0 & Swagger 2.0 specifications. Paste JSON/YAML, upload files, or fetch from URL to debug schemas instantly.

Supported Specs
OpenAPI 3.1OpenAPI 3.0Swagger 2.0YAMLJSON
Validation Features
  • Instant schema linting & error detection
  • Live documentation preview
  • Auto-convert JSON ↔ YAML
Developer API

Need to validate specs in your CI/CD pipeline? Use our validation API.

OpenAPI specification 

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No format detected yet

Why validate your OpenAPI Specification?

Ensuring your API specification (formerly Swagger) validates against the official standard is crucial for generating accurate documentation and SDKs. Our tool checks for:

Syntax Errors

Invalid JSON or YAML formatting

Schema Compliance

Adherence to OAS 3.0 or 3.1

Missing Fields

Required properties checks

Supported Versions

🚀
OpenAPI 3.1

Latest standard with webhooks support

📚
Swagger 2.0 & OAS 3.0

Full backward compatibility

How to use this OpenAPI validator?

Our validator makes it simple to check your OpenAPI specifications in four easy steps:

1
Paste or Upload

Copy your OpenAPI JSON/YAML content or upload a file directly.

2
Instant Feedback

Our validator parses your spec against official schemas in real-time.

3
Fix & Retry

View detailed error messages to quickly resolve issues.

4
Preview & Publish

Once valid, preview your documentation and publish it instantly.