OpenAPI Spec Validator

It supports both OpenAPI 3.x (3.0.x and 3.1.x) and Swagger 2.0 specs in YAML or JSON format. The validator auto-detects the format from the 'openapi' or 'swagger' field at the root level.

It validates required fields (openapi/swagger version, info.title, info.version), checks that all paths start with /, detects duplicate paths and duplicate operationIds, flags missing path parameter definitions, warns about missing operationIds and server definitions, and counts paths, operations, and schemas.

Errors are spec violations that will break tooling — missing required fields, duplicate operationIds, undefined path parameters. Warnings are best-practice issues that may cause problems with SDK generation or documentation. Info items are suggestions that improve spec quality but aren't required.

operationId is a unique identifier for each API operation. It's used by code generators (openapi-generator, Speakeasy, Kiota) to name client methods, by documentation tools for deep links, and by mocking frameworks. Duplicate or missing operationIds cause failures in most tooling pipelines.

No — all validation runs entirely in your browser using JavaScript. Your API spec never leaves your machine. No data is transmitted.

Swagger Editor provides a full IDE experience with schema-level JSON Schema validation. This tool focuses on structural correctness, operational best practices (operationId coverage, path parameter consistency, response definitions), and gives a quick lint report with path references — optimized for CI/CD checks and quick audits.