About The OpenAPI / Swagger Validator

The OpenAPI Swagger Validator reviews OpenAPI 3.x and Swagger 2.0 specs for required metadata, paths, operations, responses, and common authoring mistakes.

Validation runs locally in your browser. JSON specs get structured checks, while YAML input receives a lightweight marker check for common required blocks.

How to Validate an OpenAPI Spec Online

1. Paste your API spec into the OpenAPI or Swagger spec box.
2. Leave Include style and hygiene warnings on for stricter review.
3. Click Validate Spec to build the report.
4. Review errors and warnings before sharing the spec with tooling or teammates.

Choosing Options Correctly

Style and hygiene warnings:
- Keep it ON when reviewing a spec before handoff or CI.
- Turn it OFF when you only want basic structural errors.

JSON versus YAML:
- Use JSON for the most complete browser-side checks.
- Use YAML mode as a quick pre-check before a full YAML-aware validator.

Common Use Cases

• Pre-checking API specs before gateway import.
• Reviewing pull requests for missing responses or operation metadata.
• Finding obvious spec issues before SDK generation.
• Testing small OpenAPI examples for documentation.

Quick FAQ

Does this replace a full OpenAPI parser?
No. It provides quick checks, but production specs should be validated with the same tooling used by your docs, gateway, or SDK pipeline.

Is my API spec uploaded?
No. Validation is designed to run in the browser.

Why does YAML get lighter validation?
YAML parsing can confirm structure, but complete OpenAPI semantic validation requires deeper schema rules.

Can it validate external references?
Only if the page supports resolving them. Bundled or inline specs are more reliable in browser-only tools.