JSON to Zod Schema

Output Format

The generator outputs a complete TypeScript snippet including:

• import { z } from “zod” — Zod import
• const FooSchema = z.object({…}) — Schema definition
• export type Foo = z.infer<typeof FooSchema> — Inferred TypeScript type

Common Use Cases

• API validation: Generate schemas from API response examples to validate real responses at runtime.
• Form validation: Convert a form’s expected data shape into Zod schemas for use with react-hook-form or similar.
• Config files: Define and validate configuration objects loaded from JSON files.
• Type safety: Pair with TypeScript to get both runtime validation and static type inference from a single schema.

Example

With the root name User, this sample:

{
  "id": 42,
  "email": "alice@example.com",
  "price": 19.9,
  "tags": ["admin", "beta"],
  "metadata": null,
  "orders": [
    { "sku": "A1", "qty": 2 },
    { "sku": "B7", "qty": 1, "note": "gift" }
  ]
}

produces:

import { z } from "zod";

const UserSchema = z.object({
  id: z.number().int(),
  email: z.string(),
  price: z.number(),
  tags: z.array(z.string()),
  metadata: z.null(),
  orders: z.array(z.object({
    sku: z.string(),
    qty: z.number().int(),
    note: z.string().optional(),
  })),
});

export type User = z.infer<typeof UserSchema>;

note is optional because only one of the two orders has it. The output uses only calls that work in both Zod 3 and Zod 4.

Refining the Generated Schema

A sample shows one value per field, so the generator cannot know your rules. Check these points before you use the schema:

Use .parse() where a failure should stop the program (configuration at startup): it throws a ZodError. Use .safeParse() for API responses and user input: it returns { success: false, error } and you handle the error yourself.

Limits

• Types come from one sample. An empty array becomes z.array(z.unknown()), and an empty object becomes z.record(z.string(), z.unknown()).
• null becomes z.null(). The generator does not add .nullable(). In an array of objects, a key that is null in the first item and a string in the second becomes z.union([z.null(), z.string()]).
• Mixed arrays become a union. An array such as [{"a": 1}, 2], at the root or inside an object, gives z.array(z.union([z.number().int(), z.object({ a: z.number().int() })])). All objects in one array merge into a single z.object, so the union has one object member.
• No string formats or limits. Emails, URLs, dates, and UUIDs are all z.string().