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Generate code from JSON
Turn JSON into TypeScript, Go, Rust, or Zod — generated in your browser from one sample, with every option and the exact generator version shown. The output is a starting point, not a contract.
Strict JSON
Nothing in yet
Paste, drop, or type to begin. Everything stays on this device.
How JSON becomes TypeScript
TypeScript mapping rules
- Objects become interfaces in first-seen order; properties are required unless the nullability option makes them optional.
- JSON null infers the literal type null — a nullable property is a union, not an optional marker.
- Arrays always keep their order as array types; nested objects become their own named interfaces.
Inference rules (every language)
- quicktype-core infers one schema from ONE sample: every property it sees becomes required — absence in the sample is absence in the types.
- Inference defaults: similar objects combine into one class; UUID-like, date-time-like, integer-like, and boolean-like strings become their typed forms; heterogeneous maps infer as maps.
- Number kinds are inferred through IEEE-754 doubles: spellings like 1e400 or 30-digit integers still infer, but as doubles when they exceed the target's integer range.
- The output is a starting point: names are guesses (Top-level, and per-shape names), and review beats trust.
Letters, digits, underscores — starts with a letter or underscore.