Structured Output Validator

Validate JSON — like a model's structured output — against a JSON Schema, with per-field error paths.

5 validation errors
$.name: string shorter than minLength 2
$.email: does not match pattern ^[^@]+@[^@]+\.[^@]+$
$.age: above maximum 130
$.role: value not in enum ["admin", "member", "viewer"]
$.tags[1]: expected type "string", got "number"

Supports a practical subset of JSON Schema: type, required, properties, items, enum, minLength/maxLength, pattern, minimum/maximum, and additionalProperties. Pairs with the Tool Schema Generator.

About the Structured Output Validator

Getting a model to return valid structured output is only half the problem — you still need to verify what came back actually matches the shape you expect before using it. This tool validates arbitrary JSON against a JSON Schema and reports exactly which fields failed and why.

Key Features

  • Per-field error paths, not just a pass/fail.
  • Supports type checking, required fields, nested objects/arrays, enums, string/number bounds, and patterns.
  • Pairs naturally with the Tool Schema Generator — validate that a model's returned arguments match the schema you generated.