Validate OpenAPI 3.2, 3.1, 3.0 & Swagger 2.0 specifications. Paste JSON/YAML, upload files, or fetch from URL.
1Validating for a code generator?
Tool-specific guides to the schema errors that break client generation.
Tell us which generator or importer your spec has to satisfy — the most-requested target gets first-class support next.
Paste or upload your OpenAPI spec and click Validate to see a live preview.
Ensuring your API specification validates against the official standard is crucial for generating accurate documentation and SDKs.
Invalid JSON or YAML formatting
Adherence to OAS 3.0, 3.1 or 3.2
Required properties checks
OpenAPI 3.2
Latest release, fully supported
OpenAPI 3.1
Latest standard with webhooks
Swagger 2.0 & OAS 3.0
Full backward compatibility
OpenAPI Errors Cheat Sheet
The 8 most common validation errors with broken & fixed snippets.
Four simple steps to validate your OpenAPI specification.
Paste or Upload
Copy your OpenAPI JSON/YAML content or upload a file directly.
Instant Feedback
Our validator parses your spec against official schemas in real-time.
Fix & Retry
View detailed error messages to quickly resolve issues.
Preview & Publish
Once valid, preview your documentation and publish it instantly.
Common questions about validating OpenAPI and Swagger specifications.
Yes. Validating a spec is free and requires no account. Paste, upload, or link a JSON or YAML file and you get results immediately. An account is only needed if you want to publish hosted documentation.
OpenAPI 3.2, 3.1, and 3.0 are fully supported, along with Swagger 2.0 for backward compatibility. The validator detects the version from your spec automatically, so you do not need to select it.
Swagger 2.0 was renamed OpenAPI from version 3.0 onward, so the terms describe the same format at different versions. This tool validates both, which means a Swagger 2.0 file and an OpenAPI 3.2 file can be checked in the same place.
Yes. The format is detected from the content, and you can convert between JSON and YAML after validation succeeds.
Your spec is sent to the validation API over HTTPS to be checked and is not stored or shared. If you choose to publish documentation, only then is the spec saved to your account.
Different tools apply different rule sets. Some editors only check syntax, while this validator also checks the spec against the official JSON Schema for its version and reports missing required fields and structural problems that looser tools skip.
Yes. Switch to the URL tab and paste a public link to your spec. The file is fetched and validated in place, which is useful for specs already hosted in a repository.
Yes. The same checks are available as a GitHub Action that validates your spec on every pull request and can fail the build when a breaking change is introduced.
Every tool below runs on the same spec you just validated — no signup required.
OpenAPI Diff →
Compare two versions of a spec and flag breaking changes before release.
Mock Server →
Spin up a live mock API from your spec and test against it instantly.
cURL to OpenAPI →
Paste cURL commands and get a valid OpenAPI 3.1 spec back.
Changelog Generator →
Turn a version history of specs into a dated, readable API changelog.
GitHub Action →
Validate specs and block breaking changes in CI on every pull request.
Errors Cheat Sheet →
The 8 most common validation errors, with broken and fixed snippets.
Publish this spec as live API docs
Hosted documentation, an automatic changelog, and breaking-change alerts on every update. Free to start.