JSON to Zod Schema Generator

Updated October 18, 2026Free mock REST & WebSocket APIs

Paste sample JSON and get Zod schemas that validate it at runtime — plus the matching TypeScript types via z.infer. Nested schemas are declared before they're used, so the file compiles as-is.

Sample JSON

Paste, type, or drop a file onto the box.

Zod schema

import { z } from "zod";

export const ProfileSchema = z.object({
  avatarUrl: z.string(),
  bio: z.unknown().nullable(),
});
export type Profile = z.infer<typeof ProfileSchema>;

export const ItemSchema = z.object({
  sku: z.string(),
  qty: z.number(),
});
export type Item = z.infer<typeof ItemSchema>;

export const OrderSchema = z.object({
  id: z.string(),
  total: z.number(),
  status: z.string(),
  items: z.array(ItemSchema),
  coupon: z.string().optional(),
});
export type Order = z.infer<typeof OrderSchema>;

export const UserSchema = z.object({
  id: z.number(),
  email: z.string(),
  displayName: z.string(),
  roles: z.array(z.string()),
  profile: ProfileSchema,
  orders: z.array(OrderSchema),
  lastLogin: z.string(),
  "is-verified": z.boolean(),
});
export type User = z.infer<typeof UserSchema>;

Root nameexportAdd z.infer types.strict() objects

🔒 Runs in your browser — nothing you paste is uploaded.

How to generate a Zod schema from JSON

Paste a representative JSON sample (arrays with several items help detect optional fields).
Set the root name and choose whether to export, add z.infer types and use .strict() objects.
Copy the code, then tighten it where you know more: z.email(), z.iso.datetime(), z.enum([...]), .min(), .int().

Using the generated schema

import { UserSchema, type User } from "./schema";

const res = await fetch("/api/user/1042");
const parsed = UserSchema.safeParse(await res.json());
if (!parsed.success) console.error(parsed.error.issues);
else greet(parsed.data); // typed as User

Mapping rules

Sample	Zod
string / number / boolean	`z.string()` / `z.number()` / `z.boolean()`
missing in some items	`.optional()`
sometimes `null`	`.nullable()`
mixed types	`z.union([z.number(), z.string()])`
empty array	`z.array(z.unknown())`
nested object	its own named schema, declared first

By default Zod objects strip unknown keys when parsing; .strict() rejects them instead, which is useful for catching API changes in tests.

Related tools

Frequently asked questions

Is my JSON uploaded anywhere?

No. The conversion runs entirely in your browser with JavaScript, so your JSON never leaves your device and isn't logged or stored.

Which Zod version does the output target?

The output uses the core API (z.object, z.array, z.union, .optional, .nullable, .strict, z.infer) that works in both Zod 3 and Zod 4.

Why isn't a field detected as an email or date?

A sample can't prove a format, so strings stay z.string(). Add z.email() or z.iso.datetime() (Zod 4) yourself where you know the format.

Can I get plain TypeScript interfaces instead?

Yes — use the JSON to TypeScript converter.

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