OpenAPI Spec Validator
Validate full OpenAPI 3.x or Swagger 2.x documents for required fields and structure.
Validating OpenAPI specifications
OpenAPI documents describe REST APIs: paths, parameters, request bodies, responses, and security schemes. Invalid specs break codegen, mock servers, and contract tests in ways that surface only after teams depend on generated clients.
Validation finds broken references, incompatible schema types, and missing operation identifiers. It is the first gate before publishing a spec to partners or checking a pull request that touches public API contracts.
Version breaking changes explicitly: new required fields, removed endpoints, and stricter types should bump major versions or use separate base paths. Document deprecations in description fields so consumers can plan migrations.
Validate specs locally when they include staging URLs, internal OAuth scopes, or example tokens. Keeping validation on your machine aligns with policies that restrict uploading API descriptions to unknown SaaS tools.
Reference Guide
OpenAPI documents drive SDKs, mocks, and contract tests. Invalid specs fail codegen silently or late.
- Resolve
$refchains before publishing to consumers. - Mark required fields consistently on request bodies and parameters.
- Version breaking changes with a new path prefix or major API version.
- Redact real hostnames and API keys from shared examples.
Validate in CI on every pull request that touches the spec file.
Current mode
Operation: openapi-spec-validate
All processing runs locally in your browser. Paste input, click Run, and copy the result.
Example Input
Sample input for openapi-spec-validator
A sample loads automatically when you open this tool. Use Load Sample to reset it.