JSON to Zod, Go and Pydantic

Convert JSON into a Zod schema, a Go struct, or a Pydantic model with automatic type inference, nested types, and array detection. Free, runs entirely in your browser.

JSON to Zod, Go and Pydantic

Generate a Zod schema, Go struct, or Pydantic model from any JSON

Characters: 0

Paste JSON above to generate Zod (TypeScript)

Nested objects become separate named types. Arrays of objects are merged: a key missing from some items becomes optional, a null next to a value becomes nullable, mixed primitives become a union. Everything runs in your browser.

What is a JSON to Zod, Go and Pydantic converter?

This tool takes a JSON object and generates a matching type definition in one of three popular formats: a Zod schema for TypeScript runtime validation, a Go struct with JSON tags, or a Pydantic model for Python. Writing these by hand from an API response is slow and error prone.

CodeHelper's converter infers types recursively, extracts nested objects into their own named types, and detects array element types by merging keys across items, so the output compiles cleanly.

Key Features

  • Three targets: Zod, Go struct, and Pydantic, switchable with one click.
  • Type inference: strings, numbers (int vs float), booleans, null, arrays, and nested objects.
  • Named nested types: nested objects become reusable named schemas, structs, or classes.
  • Array detection: element types are inferred and object keys merged across items.
  • Private: the JSON never leaves your browser.

How to use the converter

  1. Paste your JSON into the input area.
  2. Pick Zod, Go, or Pydantic.
  3. Copy the generated schema or download it.

Ideal for typing REST API responses, validating request bodies, and bootstrapping models in a new TypeScript, Go, or Python project.

Frequently Asked Questions

How do I generate a Zod schema from a JSON API response?

Paste the response, keep Zod selected and set a root name. Every object becomes a z.object() constant, nested objects become their own named constants defined before they are used, and the root gets an inferred TypeScript type with z.infer. Copy the code into a .ts file and call Root.parse(data) to validate.

Why are some fields marked optional or nullable in the generated schema?

When the JSON contains an array of objects, the converter merges every item. A key that is missing from some items becomes .optional() in Zod, an omitempty tag in Go and Optional[...] = None in Pydantic. A key that is null in some items and a value in others becomes .nullable(), a pointer type in Go and Optional[...] in Pydantic. Without this the schema would reject the very data it was generated from.

How are numbers typed in Zod, Go and Pydantic?

If every sample value is a whole number the converter emits z.number().int(), int in Go and int in Pydantic. If any value has a decimal part it emits z.number(), float64 and float. JSON does not distinguish 1 from 1.0, so a field that is always a whole number in your sample is typed as an integer: widen it by hand if it can carry decimals.

What happens with keys that are not valid identifiers?

Zod keeps the original key in quotes. Go turns it into an exported PascalCase field with the original name in the json tag, using the usual initialisms such as ID and URL. Pydantic converts it to snake_case and adds a Field alias, and appends an underscore to Python keywords such as from or class so the class still compiles.

Is the JSON sent to a server?

No. The three generators run entirely in your browser with client side JavaScript. Nothing is uploaded, stored or logged, so it is safe to paste responses that contain private data.

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