Structured Output JSON Schema Validator
Check a JSON Schema for common structured-output constraints before wiring it into an LLM request.
Also useful for: structured outputs validator json schema response validator openai structured outputs schema Structured Output JSON Schema Validator
Structured Output JSON Schema Validator
Runs in your browser. Inputs are not uploaded.Structured Output JSON Schema Validator Example Run
Find schema choices that commonly break strict structured outputs.
Sample inputs
{"type":"object","properties":{"title":{"type":"string"},"tags":{"type":"array","items":{"type":"string"}}},"required":["title"],"additionalProperties":true}
Generated result
Summary: 1 warning in structured-output schema lint.
Stats
- Properties: 2
Issues
- Warning: Set additionalProperties to false for stricter structured outputs.
Output
[WARNING] general: Set additionalProperties to false for stricter structured outputs. What the Structured Output JSON Schema Validator Checks
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Valid JSON Schema object
The input must parse as a JSON object before compatibility checks run.
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Root object expectation
The checker warns when the root schema is not an object, which is the safest shape for structured responses.
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Required versus properties
Required keys are compared with declared properties so misspelled required fields do not slip through.
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Strict additional properties
additionalProperties is flagged when it is not false, because strict modes often expect closed objects.
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Composition caveats
Root anyOf, oneOf, or allOf usage is called out because provider support can be uneven.
Structured Output JSON Schema Validator Questions
- Q: Does the structured output JSON Schema validator upload my schema? A: No. Inputs are processed in your browser, and pasted content is not sent to analytics or a server.
- Q: What should I paste into the structured output JSON Schema validator? A: Paste a JSON Schema object for an LLM response shape. The most useful inputs include type, properties, required, and additionalProperties.
- Q: What can I copy or download? A: You can copy the lint report with errors, warnings, and notes.
- Q: What does the structured output JSON Schema validator not verify? A: It does not execute an LLM call, validate a real response payload, or cover every provider-specific schema restriction.
Related Tools
Updates
- v1.0.0 New 2026-05-17: Initial JSON syntax and structured-output compatibility lint added.