Free tool OpenAPI 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.

Specification 

1
No input ·

Documentation Preview

Paste or upload your OpenAPI spec and click Validate to see a live preview.

Formats
JSON / YAML
Versions
2.0 / 3.x
Cost
Free

Why validate your OpenAPI Specification?

Ensuring your API specification validates against the official standard is crucial for generating accurate documentation and SDKs.

Syntax Errors

Invalid JSON or YAML formatting

Schema Compliance

Adherence to OAS 3.0 or 3.1

Missing Fields

Required properties checks

🚀

OpenAPI 3.1

Latest standard with webhooks

📚

Swagger 2.0 & OAS 3.0

Full backward compatibility

How to use this validator?

Four simple steps to validate your OpenAPI specification.

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.