What is JSON to Zod Schema Generator?

Zod is a TypeScript-first schema validation library that lets you declare the shape and type of your data at runtime, with full TypeScript type inference. Instead of writing Zod schemas by hand from an API response or JSON blob, this tool automatically generates the schema — saving significant boilerplate, especially for deeply nested objects.

How to Use

Paste your JSON into the left panel.
Click "Generate" to produce the Zod schema.
Copy the output and paste it into your TypeScript project.
Install Zod if you haven't: npm install zod
Adjust optional fields manually if needed (add .optional() or .nullable()).

Why Use This Tool?

Generates z.object(), z.array(), z.string(), z.number(), z.boolean(), z.null() from JSON structure

Detects integer vs float (z.number().int() vs z.number())

Handles nested objects and arrays recursively

Includes TypeScript type inference (z.infer<typeof schema>)

Mixed-type arrays generate z.union() automatically

Tips & Best Practices

Zod doesn't automatically know which fields are optional — add .optional() to fields that might be undefined
For nullable fields (can be null or value), use z.string().nullable() instead of z.null()
Use .parse() to throw on invalid data, or .safeParse() to get a result object without throwing
For discriminated unions (e.g. different object shapes based on a "type" field), see z.discriminatedUnion()
Generated schemas are a starting point — review and add .min(), .max(), .email(), .url() refinements for production use

Frequently Asked Questions

What is the difference between JSON Schema and Zod?

JSON Schema is a language-agnostic specification (used in OpenAPI, form validation, etc.) that describes data shape as a JSON document. Zod is a TypeScript library that describes schemas as TypeScript code, with full type inference. Zod is preferred in TypeScript projects because it gives you runtime validation AND compile-time types from one source. JSON Schema is preferred when you need a format that works across languages or APIs.

Does the generator handle nullable fields?

JSON null values are mapped to z.null(). If a field could be either a string or null, you would change z.string() to z.string().nullable(). The generator maps the literal JSON structure — it doesn't infer which fields "could be" null from a sample. Review the output and add .nullable() where your API can return null.

How do I validate an API response with Zod?

Use schema.parse(data) or schema.safeParse(data). With fetch: const res = await fetch(url); const data = await res.json(); const validated = schema.parse(data). If validation fails, .parse() throws a ZodError with detailed path and message info. Use .safeParse() to handle the error without try/catch: const result = schema.safeParse(data); if (!result.success) console.error(result.error).

JSON to Zod Schema Generator