JSON to Zod Schema Generator

How to use JSON to Zod

1. Paste a JSON sample into the left editor. Any valid JSON works — objects, arrays, or nested structures.
2. Name the root schema using the input field above the editors. This becomes the exported variable name (e.g. UserSchema).
3. Click "Generate Zod" to produce the schema in the right panel.
4. Review the output. Nested objects become their own z.object() calls, arrays are typed with z.array(), and nulls produce z.nullable().
5. Copy into your TypeScript project and layer on refinements like .email(), .min(), or .transform() as needed.

What is Zod?

Zod is a TypeScript-first schema declaration and validation library. Unlike type-only solutions such as interfaces or type aliases, Zod schemas exist at runtime — they can parse unknown data and either return a strongly typed result or throw a detailed error. This makes Zod the go-to choice for validating API responses, form inputs, environment variables, and any boundary where data enters your application from the outside world.

The library pairs naturally with tools like React Hook Form (via @hookform/resolvers/zod), tRPC, and Next.js Server Actions, which all accept a Zod schema to validate input before your handler code runs. Writing schemas by hand is fine for small objects, but mapping a 50-field API response manually is slow and error-prone. This converter reads your JSON, walks every key recursively, infers the narrowest Zod validator for each value, and emits a ready-to-use schema in seconds.

Examples

Form validation schema

Given a registration form payload:

{
  "name": "Jane Doe",
  "email": "jane@example.com",
  "password": "s3cret!",
  "age": 30,
  "accept_terms": true
}

The generator outputs:

import { z } from "zod";

const RegistrationSchema = z.object({
  name: z.string(),
  email: z.string(),
  password: z.string(),
  age: z.number(),
  accept_terms: z.boolean(),
});

type Registration = z.infer<typeof RegistrationSchema>;

From here you would add .email() to the email field, .min(8) to the password, and .literal(true) to accept_terms.

API response type

{
  "data": {
    "id": 42,
    "status": "active",
    "created_at": "2024-11-15T08:30:00Z",
    "tags": ["production", "us-east"]
  },
  "meta": {
    "request_id": "req_abc123",
    "latency_ms": 12
  }
}

Output:

import { z } from "zod";

const DataSchema = z.object({
  id: z.number(),
  status: z.string(),
  created_at: z.string(),
  tags: z.array(z.string()),
});

const MetaSchema = z.object({
  request_id: z.string(),
  latency_ms: z.number(),
});

const ApiResponseSchema = z.object({
  data: DataSchema,
  meta: MetaSchema,
});

type ApiResponse = z.infer<typeof ApiResponseSchema>;

Nested config with arrays

{
  "service": "payment-gateway",
  "retries": 3,
  "endpoints": [
    { "url": "https://api.stripe.com/v1", "timeout": 5000 }
  ],
  "logging": {
    "level": "info",
    "redact_fields": ["card_number", "cvv"]
  }
}

Each nested object and array element is given its own typed schema, producing EndpointSchema, LoggingSchema, and a root ConfigSchema.

Common use cases

• Validating React Hook Form submissions with zodResolver — paste your form's expected shape and get a schema instantly.
• Parsing API responses safely in Next.js Server Components or tRPC procedures before passing data to the UI.
• Creating environment variable schemas (e.g. with t3-env) to fail fast on missing config at startup.
• Defining webhook payload shapes for Stripe, GitHub, or Clerk webhooks so invalid events are caught early.
• Building type-safe SDK wrappers around third-party REST APIs that lack TypeScript types.
• Generating tRPC input validators directly from example request payloads during rapid prototyping.
• Validating JSON config files loaded at runtime in Node.js CLI tools.

Frequently asked questions

What Zod version does this target?

The output uses the Zod 3.x API, which is the current stable release and the version used by the vast majority of projects. The generated schemas are forward-compatible with Zod 4 in most cases, since the core z.object / z.string / z.number API surface is unchanged.

Can I use the output with React Hook Form?

Yes. Install @hookform/resolvers, import zodResolver, and pass the generated schema to useForm({resolver: zodResolver(MySchema)});. The inferred TypeScript type keeps your form fields fully typed.

How do I add custom validation after generating?

Chain methods onto individual fields. For example, z.string().email() validates email format, z.number().int().positive() enforces positive integers, and z.string().regex(/^[A-Z]{/) checks for uppercase start. You can also use .refine() or .superRefine() for complex cross-field logic.

Does it handle nullable vs optional?

If a field's value is null in the sample JSON, the generator wraps it in z.nullable(). This means the field must be present but can be null. If you need the field to be truly optional (can be omitted entirely), add .optional() after generation.

How does it handle union types?

If an array contains elements of different primitive types, the generator uses z.any() as a safe fallback. For arrays of objects with the same shape, it infers a typed schema. You can manually refine mixed arrays into z.union([z.string(), z.number()]) after generation.

Can I generate Zod from a JSON Schema?

This tool works from raw JSON data, not from JSON Schema. However, you can generate a JSON Schema with the JSON Schema Generator first, then use the JSON sample to create a matching Zod schema here. Libraries like zod-to-json-schema can also convert in the other direction.

What about deeply nested structures?

There is no depth limit. Each nested object becomes its own named schema variable, and the parent references it by name. This keeps the output readable even for complex structures with four or five levels of nesting.

Privacy & how it works

Everything runs in your browser. Your JSON is parsed and converted to Zod code using client-side JavaScript — no data is transmitted to any server. You can confirm this by watching the network tab in DevTools. This makes it safe to paste production payloads, internal configs, or any sensitive data without risk. Other tools on JsonDevKit — including the JSON Formatter, JSON to Pydantic, and JSON Diff — work the same way.