JSON Schema to Zod Converter

Convert raw JSON or JSON Schema into runtime Zod validation schemas and TypeScript types with automatic type inference and string format detection.

Input JSON / Schema

Generated Zod & TypeScript

import { z } from "zod";

export const userSchema = z.object({
  id: z.number().int(),
  name: z.string(),
  email: z.string().email(),
  website: z.string().url(),
  isActive: z.boolean(),
  roles: z.array(z.string()),
  address: z.object({
    street: z.string(),
    city: z.string(),
    zipCode: z.string(),
  }),
  metadata: z.object({
    loginCount: z.number().int(),
    lastLogin: z.string().datetime(),
  }),
});

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

Quick Answer: Why Convert JSON Schema to Zod?

Converting JSON to Zod creates runtime validation barriers for TypeScript applications. While raw TypeScript interfaces vanish at compile time, Zod schemas execute at runtime to validate untrusted API data using schema.safeParse(data), while automatically providing static autocomplete and type definitions via z.infer<typeof schema>.

Runtime Type Safety Architecture

How Zod bridges external untrusted JSON with strict TypeScript types:

1. Untrusted JSON Input

External API response, Next.js Server Action body, form submission, or webhook payload.

2. Runtime Validation

zodSchema.safeParse(data) validates types, formats, string length, and required keys.

3. Typed Output

type User = z.infer<typeof schema> provides guaranteed type safety across your app.

JSON Value to Zod Schema Mapping Reference

JSON Data SampleInferred Zod SchemaStatic TypeScript Type
"alice@company.com"z.string().email()string
"https://api.domain.com"z.string().url()string
"2026-05-15T08:30:00Z"z.string().datetime()string
42 (Integer)z.number().int()number
true / falsez.boolean()boolean
["admin", "user"]z.array(z.string())string[]
{ "city": "Austin" }z.object({ city: z.string() }){ city: string }

Step-by-Step Case Study: Validating a Next.js Server Action with Zod

Here is how you use the generated Zod schema to secure a Next.js Server Action against malformed user inputs:

"use server";

import { z } from "zod";

const createUserSchema = z.object({
  name: z.string().min(2, "Name must be at least 2 characters"),
  email: z.string().email("Invalid email address"),
  role: z.enum(["admin", "editor", "viewer"]).default("viewer"),
});

export async function createUserAction(formData: FormData) {
  const rawData = {
    name: formData.get("name"),
    email: formData.get("email"),
    role: formData.get("role"),
  };

  const validation = createUserSchema.safeParse(rawData);

  if (!validation.success) {
    return { success: false, errors: validation.error.flatten().fieldErrors };
  }

  // validation.data is 100% type-safe
  await db.user.create({ data: validation.data });
  return { success: true };
}

Frequently Asked Questions

What is Zod and why is it preferred over raw TypeScript interfaces?
TypeScript interfaces only exist during compile-time and are completely stripped away in compiled JavaScript bundles. Zod provides runtime schema validation that checks external data (such as API payloads, database rows, URL query params, and form submissions) at runtime while automatically generating compile-time TypeScript types via z.infer<typeof schema>, ensuring 100% end-to-end type safety.
How does the converter detect specialized string formats like Email and URL?
The parser inspects JSON keys and values. If property names contain 'email', 'url', 'uri', 'website', or match ISO date patterns (YYYY-MM-DDTHH:mm:ssZ), it automatically enriches the schema with format validators such as z.string().email(), z.string().url(), or z.string().datetime().
Does this tool support official JSON Schema Draft-07 and Draft 2020-12 specifications?
Yes. You can paste either raw sample JSON payloads or formal JSON Schema definitions containing 'type', 'properties', 'required', and 'format' arrays. The engine parses the JSON schema and sets non-required fields to .optional().
How do you handle safe parsing in Zod without throwing runtime errors?
Instead of calling schema.parse(data) which throws a ZodError on failure, use schema.safeParse(data). It returns a discriminated union: if result.success is true, result.data contains the validated typed data; if false, result.error contains detailed field-by-field validation issues.
How does Zod compare to Yup, Joi, and Valibot?
Zod is TypeScript-first with zero external dependencies and seamless static type inference. Joi is heavier and designed for Node.js backends. Yup is popular with Formik/React forms but has looser TypeScript integration. Valibot is an ultra-lightweight alternative with modular tree-shaking.
Can I use Zod schemas in Next.js Server Actions and tRPC?
Yes! Zod is the standard validation library in tRPC procedures, React Hook Form (via @hookform/resolvers/zod), and Next.js 14/15 Server Actions (with packages like next-safe-action or native form validation).
How do I make a field optional in Zod?
Append .optional() to any schema definition (e.g. z.string().optional() or z.number().optional()). For nullable fields that can accept null from SQL databases, use .nullable() or .nullish() (which accepts both null and undefined).

Related Tools