JSON to TypeScript, Pydantic, Zod & JSON Schema

No. All parsing and code generation runs in your browser with vanilla JavaScript. The JSON you paste never leaves the page and is never sent to a server — safe for payloads that contain real data.

It merges every element into one shape. A key present in some elements but not others becomes optional, and a key whose value type differs across elements becomes a union. That makes a multi-element array a better schema source than a single object.

When a model returns structured output or tool-call arguments, you get JSON you have to validate before trusting it. A Pydantic model (Python) or Zod schema (TypeScript) turns your example into a runtime validator, so a malformed model response fails loudly at the boundary instead of corrupting logic three calls deeper. Some frameworks want the model class itself rather than a hand-written schema — the OpenAI Agents SDK takes a Pydantic class as an agent’s output_type and derives the JSON Schema from it, which the multi-agent walkthrough sets up step by step. Paste a sample payload above and you have that class already written.

Yes. Inference from a single example only sees the keys in that example. If a field is sometimes absent or nullable, paste an array of several representative objects so the merge marks those keys optional — or hand-edit the generated types. This tool gets you 90% of the way, not a substitute for a real spec.