Draft 2020-12 · local validation

Structured Output Validator

Check whether a JSON Schema is structurally valid, then optionally test a JSON output against it. This checks the base standard; provider-specific restrictions are not included.

Schema

Paste JSON or YAML Schema. Validation runs locally in a worker.

JSON Schema input

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For schemas without $schema, explicitly validate as Draft 2020-12Optional example output (JSON)

Validation results

Ready to validate

Load an example or paste your own schema, then select Analyze.

What this checks

A structured output schema describes the shape and constraints of JSON values. This validator checks the schema against JSON Schema Draft 2020-12, then validates an optional example output against the schema. A valid schema and a matching output are separate results.

Dialect and references

Draft 2020-12 is supported. Draft 2019-09, Draft-07, Draft-06, and Draft-04 declarations are recognized but not validated here. When $schema is absent, the checkbox makes the Draft 2020-12 assumption explicit. Local $defs and JSON Pointer references work; external references are never fetched.

Formats and privacy

format is treated as an annotation in this version and is not asserted. Inputs are parsed and validated in a browser worker, with no server submission or automatic persistence. Analysis has input size and execution limits to protect responsiveness.

Source and limits

Rules: JSON Schema Draft 2020-12. Last verified: 2026-10-07. This project is not affiliated with JSON Schema. Instance validation reports the first failure for a given input; additional problems may remain. This base validator does not apply provider rules or rewrite schemas; use the compatibility tools for those workflows. Both inputs have a 256 KiB limit and analysis stops after ten seconds.

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