JSON Schema to Zod

What is converted

• Types and formats: string, number, integer (z.int()), boolean, null, and formats such as email, uri, uuid, date-time and ipv4 as z.email(), z.url() and so on.
• Limits: minLength, maxLength, pattern, minimum, maximum, exclusive limits, multipleOf, minItems and maxItems.
• Objects: required (other properties are .optional()), default (.default()), additionalProperties: false (z.strictObject) or a schema (.catchall()), and maps (z.record).
• Combinations: enum, const, anyOf and allOf (as .extend() for the common base-plus-properties pattern); oneOf with a shared tag property becomes z.discriminatedUnion.
• References: $defs and definitions become named schemas, declared before use; recursive ones use getters, which Zod 4 needs for recursive types.
• OpenAPI 3.0: nullable: true becomes .nullable().

How to use the JSON Schema to Zod

1. Paste a JSON Schema, or press Sample.
2. Set the root name (the schema's title is used by default).
3. Read the notes for anything that wasn't converted.
4. Copy the code or download it as a .ts file. It needs zod version 4.

Examples

{"title":"User","type":"object","properties":{"id":{"type":"integer","minimum":1},"email":{"type":"string","format":"email"},"role":{"enum":["admin","member"]},"address":{"type":"object","properties":{"city":{"type":"string"}},"required":["city"]}},"required":["id","email"]}

import { z } from "zod";

export const UserSchema = z.object({
  id: z.int().min(1),
  email: z.email(),
  role: z.enum(["admin", "member"]).optional(),
  address: z.object({
    city: z.string(),
  }).optional(),
});
export type User = z.infer<typeof UserSchema>;

{"title":"Tree","$ref":"#/$defs/node","$defs":{"node":{"type":"object","properties":{"name":{"type":"string"},"children":{"type":"array","items":{"$ref":"#/$defs/node"}}},"required":["name"]}}}

import { z } from "zod";

export const NodeSchema = z.object({
  name: z.string(),
  get children() {
    return z.array(NodeSchema).optional();
  },
});
export type Node = z.infer<typeof NodeSchema>;

export const TreeSchema = NodeSchema;
export type Tree = z.infer<typeof TreeSchema>;

{"title":"Admin","$defs":{"base":{"type":"object","properties":{"id":{"type":"string"}},"required":["id"]}},"allOf":[{"$ref":"#/$defs/base"},{"properties":{"level":{"type":"integer","maximum":5}},"required":["level"]}]}

import { z } from "zod";

export const BaseSchema = z.object({
  id: z.string(),
});
export type Base = z.infer<typeof BaseSchema>;

export const AdminSchema = BaseSchema.extend({
  level: z.int().max(5),
});
export type Admin = z.infer<typeof AdminSchema>;

Options

Root name

The root schema is exported as <name>Schema; by default the schema's title, or Root.

Export types

Export a TypeScript type for each schema with z.infer (on by default).

Descriptions

Keep descriptions as .describe(), which also appears in JSON Schema generated back from Zod.

Limitations

• Not converted (listed in the notes): uniqueItems, patternProperties, propertyNames, not, if/then/else, contains, dependentRequired and the unevaluated keywords.
• $refs to other files or URLs aren't fetched.
• oneOf without a tag property becomes z.union(), which doesn't check that only one option matches.

Frequently asked questions