JSON to Zod Schema Online – Generate Zod Validators

Infer a Zod 4 validator from one JSON sample and copy editable TypeScript code without uploading data.

Runs locally
Ready to generate

Generates Zod 4 syntax from one observed JSON sample. Install zod in your TypeScript project before using the copied code. No data leaves this browser.

Paste JSON (up to 200,000 characters).

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TypeScript schema and inferred type; review before production use.

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JSON to Zod guide

How to generate a Zod schema from JSON

Paste a valid JSON sample to generate a Zod 4 schema with inferred primitive types, nested objects, array elements, and an exported inferred TypeScript type. The entire transformation happens in your browser; sample payloads are not sent to VetaTool servers. This tool is free to use. No account or payment is required.

Last updated

What you can do here

  • Zod 4 TypeScript code generation
  • Nested objects and arrays
  • Observed union types
  • Null and special-key handling
  • Warnings for incomplete sample evidence
  • Syntax and size errors
  • Copyable code
  • Browser-local processing

How to use

  1. Paste one valid JSON document into the sample input.
  2. Select Generate Zod schema to inspect the derived Zod 4 code.
  3. Review warnings for empty collections, unknown structures, and limitations of one sample.
  4. Copy the code, install zod in your project, and refine optionality and business constraints manually.

Zod schemas inferred from JSON values

JSON strings, booleans, numbers, null, nested objects, and arrays map to Zod validators. Generated object property keys are quoted or computed when necessary, including keys that are not valid identifiers.

Arrays use their observed item types. When several different types occur, the generator emits a Zod union. It does not evaluate JavaScript contained in input strings or execute the resulting code in your browser.

Single samples cannot define your entire API contract

A field present in one JSON sample is emitted as required because the sample does not reveal whether it is optional in other responses. Numbers do not establish ranges, and strings do not establish email or URL formats.

Empty arrays have unknown element types. Empty objects provide no information about expected keys. Inspect the generated validator with additional representative examples before relying on it for production data.

  • The output targets Zod 4 and uses import { z } from the zod package.
  • Parsing, schema inference, and code generation run locally.
  • An invalid or oversized sample produces an error, not partial code.

When to use JSON Schema instead of Zod

Use JSON Schema when the contract must be shared across programming languages or with API specification tooling. Use JSON to TypeScript when you need compile-time types only, without runtime validation.

Zod can be a convenient starting point for TypeScript applications, but automatically inferred shapes must be reviewed for edge cases and actual server-side validation rules.

Nested JSON to Zod example

Infer a nested object and a string array from one JSON payload.

JSON sample

{"user":{"name":"Ada"},"roles":["admin","editor"]}

Zod code

import { z } from "zod";

export const schema = z.object({
  ["user"]: z.object({
    ["name"]: z.string(),
  }),
  ["roles"]: z.array(z.string()),
});

export type Inferred = z.infer<typeof schema>;

Common questions

Frequently asked questions

Does this generator send my JSON sample to a server?

No. It parses and generates code in the browser. Raw input and generated code are not included in anonymous Analytics events.

Does the generated schema cover optional fields and string formats?

Not automatically. A single example cannot determine optional fields, email addresses, URL formats, or business-specific restrictions. Review and refine the generated code.

What Zod version does the generated code target?

Zod 4. The generated code imports z from zod and includes an inferred TypeScript type. Install zod separately in your project.

How are empty arrays and mixed item types handled?

Empty arrays become z.array(z.unknown()) with a warning. Mixed array items are represented with z.union using the observed types.

Can I generate a schema from invalid JSON?

No. Correct JSON syntax first using JSON Validator or JSON Error Checker; the generator does not attempt to guess or repair an invalid sample.

Recommended next steps

JSON to TypeScript OnlineGenerate compile-time interfaces instead of runtime validators.JSON Schema Generator OnlineInfer a portable JSON Schema contract.JSON Schema Validator OnlineValidate samples against a separately specified JSON Schema.

Debugging a specific JSON issue? Browse JSON troubleshooting.