JSON to Zod Schema
Paste JSON to generate Zod validation schemas with full nested type inference and runtime validation.
About This Tool
The JSON to Zod Schema converter is a free browser-based tool that automatically generates Zod validation schemas from any JSON data. Instead of manually writing schema definitions for API request validation, form inputs, or environment variable parsing, you can paste the raw JSON and get accurate, ready-to-use Zod schemas in milliseconds.
The converter performs recursive type inference across your entire
JSON structure. Primitive values are mapped to their corresponding
Zod validators — z.string(), z.number(),
z.boolean(), and z.null(). Integer values are
detected and annotated with z.number().int() for stricter
validation. Nested objects are extracted into their own named
schema constants, with names derived from the field key (for
example, an address field produces an addressSchema
constant). Arrays are analyzed to determine a consistent element
type; if the array contains mixed types, a z.union() is
generated automatically. Empty arrays default to
z.array(z.unknown()) so you can refine them later.
All processing happens entirely in your browser. Your JSON data never leaves your machine — there are no server round-trips, no logging, and no third-party analytics on your input. This makes it safe for sensitive payloads such as internal API responses, authentication tokens, and configuration files that contain secrets. If you also need TypeScript interfaces, try our JSON to TypeScript converter.
Additional options let you customize the output to match your
project's validation requirements. You can toggle .optional()
to mark all fields as optional for partial validation schemas,
add .nullable() modifiers for fields that accept null
values, or enable .strict() mode to reject unknown keys.
The root schema name is configurable so the generated code
integrates directly into your codebase. For related conversions,
check out our JSON Schema Generator
and JSON to Python tools.
How to Use
- Paste or type your JSON into the JSON Input panel on the left.
- The Zod schema output updates automatically in the right panel as you type.
- Set the Root name field to customize the top-level schema variable name (defaults to "Root").
- Enable .optional() to mark all fields as optional for partial validation schemas.
- Enable .nullable() to add nullable modifiers to all fields for APIs that return null values.
- Enable .strict() to generate strict object schemas that reject unknown keys.
- Click Copy or press Ctrl+Shift+C to copy the generated Zod schema to your clipboard.
Popular JSON to Zod Schema Examples
FAQ
What is Zod and why should I use it?
Zod is a TypeScript-first schema declaration and validation library. Unlike TypeScript interfaces which only exist at compile time, Zod schemas validate data at runtime. This makes them essential for validating API responses, form inputs, environment variables, and any data that crosses a trust boundary. Zod also infers TypeScript types from schemas, giving you both compile-time and runtime safety from a single source of truth.
How does the tool handle nested objects?
Each nested object is extracted into its own named Zod schema constant. The name is derived from the field key using camelCase conversion with a 'Schema' suffix. For example, a field called shipping_address produces a shippingAddressSchema constant. If a name collision occurs, a numeric suffix is appended automatically (addressSchema, addressSchema2, etc.).
What happens with arrays of mixed types?
The converter inspects every element in the array and collects all distinct Zod types. If all elements share the same type, a simple z.array() is produced (e.g. z.array(z.string())). If multiple types are found, a z.union() is generated inside the array (e.g. z.array(z.union([z.string(), z.number()]))). Empty arrays default to z.array(z.unknown()).
Is my data safe?
Yes. All schema generation runs entirely in your browser using JavaScript. No data is sent to any server. You can verify this by checking the Network tab in your browser's developer tools while using the tool.
What is the difference between .optional() and .nullable()?
In Zod, .optional() means the field can be undefined (or absent from the object), while .nullable() means the field can be null. You can combine both: z.string().nullable().optional() accepts string, null, or undefined. Use .optional() for fields that may be missing from API responses, and .nullable() for fields that explicitly return null.
What does strict mode do?
When strict mode is enabled, the generated schemas use z.object({...}).strict() instead of plain z.object({...}). Strict mode causes Zod to throw an error if the input object contains any keys not defined in the schema. This is useful for validating API request bodies where you want to reject unexpected fields.
Can I use the generated schemas with z.infer to get TypeScript types?
Yes. The generated code includes type inference statements like 'type Root = z.infer<typeof rootSchema>'. This gives you both runtime validation and compile-time type safety from the same schema definition, which is one of Zod's biggest advantages over separate type definitions.
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