OpenAPI Validator — Check OpenAPI & Swagger Specs Online
OpenAPI Validator
Validate OpenAPI 2.x (Swagger) and 3.x specs. Accepts YAML or JSON.
#What this tool does
Paste an OpenAPI spec in YAML or JSON and get validation results with error details. Supports OpenAPI 2.0 (Swagger), 3.0.x, and 3.1.x — the version is auto-detected from the swagger or openapi field.
A valid spec means code generators, documentation tools, and API gateways will parse it correctly. An invalid spec causes silent downstream failures — generated SDKs with missing methods, broken gateway routes, documentation gaps.
If you need to convert between YAML and JSON, use YAML to JSON or JSON to YAML.
#Common errors
Unquoted response codes — 200: is parsed as an integer in YAML. Use "200": (quoted string).
Invalid $ref references — typos in #/components/schemas/... paths silently break code generation.
Missing info or paths — both are required at the root. Even an empty paths: {} satisfies the schema.
Make sure your YAML syntax is valid first — the YAML validator catches syntax-level issues before you validate the OpenAPI structure.
#Open source
This tool is powered by @azin-tech/mini-tools, an open-source developer toolkit. View source on GitHub.
Auto-deploy into your own cloud
Push code, AZIN handles the rest. Auto-detected builds, your cloud account, no vendor lock-in.