OpenAPI Validator Online — Schema Conformance Check
Check OpenAPI 3.0–3.2 schema conformance locally. JSON and YAML — external $ref are never fetched.
Developer notes
• Uses @scalar/openapi-parser via dynamic import (validate only). • Supports OpenAPI 3.0, 3.1, and 3.2. • Live debounced validation; Monaco input with JSON/YAML auto-detect. • External / URL $ref are never fetched. • Internal #/… references are checked by Scalar validate (broken refs fail). • Swagger 2.0 is rejected with a clear message. • Max input 512 KiB. • Results panel shows verdict, Scalar issue paths, and spec stats.
Use cases
• Catch missing info, invalid openapi versions, and schema errors before CI. • Paste a single-file spec (JSON or YAML) for a quick local check. • Confirm internal $ref targets resolve.
Examples
Valid minimal spec
Before
After
Swagger 2 rejected
Before
After
Validate OpenAPI FAQ
Common questions
What does validate check?
Schema conformance for OpenAPI 3.0–3.2 via @scalar/openapi-parser. It is not a style linter — use Lint OpenAPI for that.
Are $ref supported?
External and URL $ref are never fetched. Internal #/… references are checked: missing targets fail validation.
Is Swagger 2.0 supported?
No. Documents with a swagger key are rejected with a clear message. These pages do not claim Swagger validation.
JSON and YAML?
Both. Auto-detect with BOM strip; if a {…} document fails as JSON, YAML flow fallback is tried.
Related tools?
See also JSON Validator, Beautify YAML, and the API tools hub.
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