TypeScript to Zod Schema Converter

You have TypeScript interfaces defining your data models, and now you need runtime validation with Zod. Manually rewriting every interface as a Zod schema means duplicating each property with z.string(), z.number(), z.optional(), and z.array() — tedious and error-prone when the interface has 20+ fields with nested objects.

What Is Zod?

Zod is a TypeScript-first schema validation library. Unlike TypeScript types that only exist at compile time, Zod schemas validate data at runtime — parsing API responses, form inputs, environment variables, and any data crossing a trust boundary. Zod schemas can also infer TypeScript types via z.infer<typeof schema>, keeping your types and validation in sync.

How This Converter Works

Paste a TypeScript interface, type alias, or a set of types, and the tool generates the equivalent Zod schema code:

1. Primitive types: string → z.string(), number → z.number(), boolean → z.boolean()
2. Optional fields: name?: string → name: z.string().optional()
3. Arrays: string[] or Array<string> → z.array(z.string())
4. Nested objects: Inline object types and referenced interfaces become nested z.object() calls
5. Union types: string | number → z.union([z.string(), z.number()])
6. Literal types: "active" | "inactive" → z.enum(["active", "inactive"])
7. Nullable: string | null → z.string().nullable()

Common Use Cases

API route validation — Define your request body as a TypeScript interface, then generate a Zod schema to validate incoming requests in Next.js API routes, Express middleware, or tRPC procedures.

Form validation — React Hook Form and Formik both support Zod schemas as validation resolvers. Convert your form data interface to a Zod schema for consistent client-side validation.

Environment variable parsing — Convert your env config interface to a Zod schema, then use z.parse(process.env) to validate and type-narrow environment variables at startup.

Config file validation — Validate JSON or YAML configuration files against Zod schemas generated from your TypeScript config types.

Working with the Output

The generated schema is a starting point. After copying, you may want to:

• Add refinements: .min(), .max(), .email(), .url(), .regex() for string constraints
• Add transforms: .transform() to coerce or normalize values during parsing
• Add defaults: .default() for fields with default values
• Replace broad types: Swap z.string() with z.enum() for fields with known values

Frequently Asked Questions

Q: Does this handle generic types like Promise<T> or Record<K, V>? A: The converter handles common generics like Array<T>, Record<string, T>, and Partial<T>. Complex generics like custom generic interfaces require manual adjustment after conversion.

Q: What TypeScript features are not supported? A: Mapped types, conditional types, template literal types, and keyof expressions cannot be directly converted to Zod because they require type-level computation. The tool converts concrete types and interfaces.

Q: Can I convert multiple interfaces at once? A: Yes. Paste multiple interfaces or type aliases and the tool generates a separate Zod schema for each one, preserving references between them.

Q: Is my code sent to a server? A: No. All parsing and conversion happens entirely in your browser. Your TypeScript code never leaves your device.

Q: Why Zod instead of Yup or Joi? A: Zod is designed for TypeScript-first workflows with full type inference via z.infer. Unlike Yup and Joi, Zod schemas are the single source of truth for both runtime validation and compile-time types, eliminating type drift.