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OpenAPI / Swagger Spec Validator

DataDeveloper

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INPUT

Auto Process

OUTPUT

Client Side

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Guide

OpenAPI / Swagger Spec Validator

Validate your OpenAPI 3.0, 3.1, or Swagger 2.0 specifications instantly. Paste YAML or JSON, get a structured list of errors and warnings with JSON Pointer paths, and pretty-print your spec for clean documentation.

How to Use

Paste your OpenAPI or Swagger spec into the input field. The validator automatically detects whether it is YAML or JSON and which specification version you are using. Results show a summary of endpoints, schemas, errors, and warnings. Each issue includes a JSON Pointer path so you can locate the problem quickly.

Features

Multi-Version Support – Validates Swagger 2.0, OpenAPI 3.0.x, and OpenAPI 3.1.x specifications
Structural Validation – Checks required fields (info, paths, version), correct types, and schema structure
Semantic Validation – Detects duplicate operationIds, invalid HTTP methods, broken $ref references, and path parameter inconsistencies
Error Paths – Every issue includes a JSON Pointer path for precise location
Pretty-Print – Reformat your spec as clean JSON or YAML with proper indentation
Spec Summary – Instant overview: version, total endpoints, schemas, errors, and warnings
100% Client-Side – Your API specs never leave your browser

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 FAQ

What is the difference between Swagger 2.0 and OpenAPI 3.0?

Swagger 2.0 was the original API specification format developed by SmartBear. When the specification was donated to the OpenAPI Initiative in 2015, it was renamed to OpenAPI. Version 3.0 introduced significant improvements including better support for callbacks, links, multiple servers, and a cleaner component structure. The two formats are not directly compatible.
Why do operationIds need to be unique in an OpenAPI spec?

operationIds serve as unique identifiers for each API operation. Code generators use them to create method names in client SDKs, documentation tools use them for anchor links, and testing frameworks use them to reference specific endpoints. Duplicate operationIds cause conflicts in all of these downstream tools.
What is a JSON Pointer and how do I read validation error paths?

A JSON Pointer (RFC 6901) is a string syntax for identifying a specific value within a JSON document. For example, /paths/~1users/get/parameters/0 points to the first parameter of the GET /users operation. The ~1 escapes a forward slash in the path segment. Reading these pointers tells you exactly where in your spec the validation error occurs.
Should I write my OpenAPI spec in YAML or JSON?

Both formats are fully supported and functionally equivalent. YAML is generally preferred for hand-written specs because it is more readable and supports comments. JSON is better for machine-generated specs and programmatic manipulation. Most tools accept either format, so choose whichever your team finds easier to maintain.