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How do I generate a Zod schema from JSON?

Paste sample JSON data and the tool infers a Zod validation schema with auto-detected types including email, URL, UUID, and datetime formats. Toggle options like .optional(), .strict(), coerce mode, and z.infer type alias. Copy the output and use it directly in your TypeScript project. Everything runs in your browser.

Generate Zod schema from types
Input
interface User {
  id: number;
  name: string;
  email: string;
  role: "admin" | "user";
}
Output
const UserSchema = z.object({
  id: z.number(),
  name: z.string(),
  email: z.string().email(),
  role: z.enum(["admin", "user"]),
});

type User = z.infer<typeof UserSchema>;
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Zod Schema Generator

Generate Zod validation schemas from JSON data. Detects emails, URLs, UUIDs, dates, integers, and nested objects automatically.

About Zod Schema Generator

  • Zod is the most popular TypeScript-first schema validation library, used with tRPC, React Hook Form, Next.js server actions, and more.
  • Format inference — detects emails, URLs, UUIDs, and ISO dates in string values and applies .email(), .url(), .uuid(), .datetime() refinements.
  • Integers — whole numbers get .int(), decimals stay as z.number().
  • .strict() — rejects objects with unknown keys at runtime, great for API input validation.
  • Coerce — uses z.coerce.string() etc. to auto-convert incoming values (useful for form data and query params).
  • Type inference — generates a z.infer<typeof schema> type alias so you get TypeScript types for free.
  • Everything runs in your browser — no data is sent over the network.

Tips & Best Practices

Pro Tip

Use z.infer<typeof schema> to keep types and validation in sync

Define the Zod schema once and derive the TypeScript type from it. This guarantees your type definition and runtime validation are always identical. No more 'type says string but validation allows number' bugs.

Common Pitfall

z.object() is strict about extra keys by default — z.passthrough() isn't

z.object({name: z.string()}).parse({name: 'test', extra: true}) strips the extra key silently. Use .strict() to reject unknown keys, or .passthrough() to preserve them. The default behavior (strip) can silently lose data.

Real-World Example

Chain .transform() for coercion + validation in one step

z.string().transform(Number).pipe(z.number().min(0).max(100)) validates that input is a string, coerces it to a number, then validates the number is 0-100. This handles form inputs where everything starts as a string.

Security Note

Always validate API inputs with Zod at the boundary

TypeScript types disappear at runtime. A malicious API request can send any shape of data. Use Zod schemas as middleware to validate and sanitize every incoming request body, query parameter, and path parameter before your business logic touches it.

Frequently Asked Questions

How do I generate a Zod schema from JSON data?
Paste a JSON object or array and DevBolt infers the Zod schema from the structure: strings become z.string(), numbers z.number(), booleans z.boolean(), arrays z.array(), and nested objects z.object(). The generator detects common formats like emails, URLs, UUIDs, and dates, adding refinements like .email() or .url() automatically. You can also input JSON Schema for more precise conversion since constraints map directly to Zod methods.
What is Zod and why use it for runtime validation in TypeScript?
Zod is a TypeScript-first schema validation library that checks data at runtime. Unlike TypeScript types that only exist at compile time, Zod validates when your application runs — critical for API responses, form inputs, environment variables, and external data. Zod schemas infer TypeScript types via z.infer, defining validation and types from a single source of truth. It integrates with React Hook Form, tRPC, Astro, Next.js server actions, and many frameworks.
How do I add custom validation rules to a generated Zod schema?
Chain Zod's validation methods onto the generated schema: .min()/.max() for constraints, .email()/.url()/.uuid() for formats, .optional()/.nullable()/.default() for optionality, .nonempty() for arrays, and .refine()/.superRefine() for custom logic like password confirmation matching. Transform data during parsing with .transform() to coerce types or normalize formats. If you input JSON Schema with constraints, these methods are generated automatically.

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