JSON to JSON Schema.

Frequently asked questions.

How does this differ from /validate?

/validate checks a JSON document against a schema you wrote. This page does the opposite: it takes a sample JSON document and produces a schema you can hand-edit.

Which draft does it emit?

Draft 2020-12 by default. Switch to Draft 07 in settings for legacy tooling.

Does it detect formats like email or uuid?

Only ISO-8601 date-time strings are detected automatically. Other `format` values are an opt-in choice — open the generated schema and add them where appropriate.

How are arrays with mixed item shapes handled?

Object items are unified property-by-property, and `required` lists only the keys present in every observed item. Mixed-type items (e.g. `[1, "a"]`) are wrapped in `oneOf`.

Does my data leave my browser?

No. Inference is plain TypeScript that runs locally. No network round-trip and no server.

More JSON tools.

• FormatPretty-print JSON with line-accurate errors. Sort keys on demand.
• ValidateCheck a JSON document against a JSON Schema. Per-path error messages.
• MinifyStrip whitespace and shrink your JSON payload. Reports bytes saved.
• Tree ViewBrowse JSON as a collapsible tree. Drill into nested data without scrolling.
• Semantic DiffCompare two JSON files by structure. Per-path adds, removes, modifications.
• JSONPath / JMESPathRun live JSONPath and JMESPath queries against your JSON.