JSON to Types

Generate types, serializers, validation schemas and Mermaid diagrams from a JSON sample.

Runs locally in your browser. Your input is not uploaded or saved.

Generate

Root type name

JSON sample

TypeScript types

Types describe the supplied sample. Every array entry is considered; fields missing from some object entries become optional. Dates, UUIDs and URLs remain strings. A sample cannot establish every allowed value or whether a field is always required.

Strict JSON only. Need to format JSON or convert a Python dictionary? Open JSON Formatter.

Up to 100,000 characters, 10,000 values, 40 nesting levels and 200 object shapes. Duplicate keys keep the last value. Numbers use JavaScript parsing; large integers outside its safe range are rejected.

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