JSON to Zod Schema Generator Online
Auto-generate TypeScript interfaces from any JSON โ nested objects ยท optional fields ยท readonly ยท export ยท 100% Free
export interface User {
id: number;
name: string;
active: boolean;
address: Address;
}Zod is the leading TypeScript-first schema validation library โ and generating Zod schemas from JSON saves you from writing verbose z.object() definitions by hand. This generator converts your JSON structure to a complete Zod schema with proper validators for each type, ready to use for API response validation, form validation and runtime type checking.
What is JSON to TypeScript Interface Generation?
This tool analyses the structure of your JSON data and automatically generates TypeScript interface or type declarations โ saving you the time of writing them manually. It infers string, number, boolean, null, nested object interfaces, and typed arrays. When your JSON is an array of objects, optional fields are detected automatically.
How Nested Objects Are Handled
Every nested JSON object generates its own named TypeScript interface. For example, if your JSON has "address": { "city": "Ahmedabad" }, the tool generates a separate Address interface and references it as address: Address in the parent interface โ matching real-world TypeScript project structure.
Frequently Asked Questions
What is Zod and why use it over TypeScript interfaces?
TypeScript interfaces only exist at compile time โ they're erased at runtime. Zod schemas exist at runtime and validate actual data. Use Zod when: validating API responses at runtime, validating form input, ensuring external data matches expected shape. Zod also generates TypeScript types: type User = z.infer<typeof UserSchema> โ one source of truth for runtime and compile-time types.
What Zod validators are generated for different JSON types?
string โ z.string(). number โ z.number(). boolean โ z.boolean(). null โ z.null(). array โ z.array(itemType). object โ z.object({...}). string or null โ z.string().nullable(). optional field โ z.string().optional(). The generator produces the correct Zod validator chain for each detected type.
How do I add validation rules to generated Zod schema?
Generated schemas provide basic type validation. Add rules manually: z.string().email() for email, z.string().min(1) for non-empty, z.number().min(0).max(100) for percentage, z.string().url() for URLs, z.date() for dates. The generator gives you the structure โ you add business rules. This separation keeps generated code clean and manual refinements intentional.
Can Zod validate and transform JSON at the same time?
Yes โ z.transform(): const DateSchema = z.string().transform(s => new Date(s)) converts string to Date object during parsing. z.preprocess(): handles data before schema validation. z.coerce: z.coerce.number() converts "42" (string) to 42 (number). This makes Zod ideal for API response parsing where you want transformation + validation in one step.