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JSON to Zod Schema

Paste a sample JSON value and generate a Zod schema plus an inferred TypeScript type, so one shape validates at runtime and types at compile time.

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About this tool

The JSON to Zod Schema tool turns a pasted JSON sample into a ready-to-use Zod schema and the matching TypeScript type. Zod is the dominant TypeScript validation library, and hand-writing z.object trees for real API payloads is slow and error-prone. This converter parses your JSON with JSON.parse, walks the value recursively, and emits idiomatic Zod: strings become z.string(), integers z.number().int(), other numbers z.number(), booleans z.boolean(), null z.null(), and nested objects their own named z.object({...}) schemas.

Everything runs locally in your browser — your JSON is parsed in-page and never uploaded, so sensitive payloads stay on your device. Arrays infer their element type by deep-merging every element, so an array of objects with slightly different keys produces one schema where keys missing from some elements are marked .optional(). ISO-8601 date-time strings are recognised and emitted as z.string().datetime(). Object keys that are not valid identifiers are safely quoted.

The output is a complete module: an exported const for each object schema (children defined before the parents that reference them) followed by export type Root = z.infer<typeof Root>, so you get compile-time types for free. Use the root-name box to rename the top-level schema, and the missing-key toggle to treat absent keys as .optional() (default) or .nullable(). Copy the result or download it as a .ts file.

Frequently asked questions

How are JSON types mapped to Zod?
string to z.string(), an ISO date-time string to z.string().datetime(), integers to z.number().int(), other numbers to z.number(), booleans to z.boolean(), null to z.null(), arrays to z.array(...), and objects to a named z.object({...}). Empty arrays become z.array(z.unknown()).
How are optional or nullable fields handled?
When an array's elements or merged siblings lack a key, that key is marked .optional(). A value seen as null becomes z.null() or adds .nullable(). The missing-key toggle lets you emit .optional() (default) or .nullable() for keys absent from some samples.
Does it also give me a TypeScript type?
Yes. After the schema it emits export type Root = z.infer<typeof Root>, so the inferred static type is derived from the schema itself — one source of truth for both runtime validation and compile-time types.
Is my JSON uploaded anywhere?
No. Parsing and code generation happen entirely in your browser with JSON.parse and plain JavaScript. Nothing is sent to a server, so you can safely paste private API responses.

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