Zod Schema Generator

Zod is a TypeScript-first schema declaration and validation library. You define a schema once and get TypeScript type inference automatically. It's widely used for validating API inputs, environment variables, form data, and more. Unlike io-ts, Zod has a chainable, ergonomic API — z.string().min(1).email() reads like what it does.

z.infer<typeof schema> extracts the TypeScript type from a Zod schema. Instead of defining your TypeScript interface separately and keeping it in sync with validation logic, you define the Zod schema once and derive the type from it: const userSchema = z.object({ name: z.string() }); type User = z.infer<typeof userSchema>; — User is automatically { name: string }.

optional() adds undefined to the type (string | undefined) — useful for optional object keys where the key may be absent. nullable() adds null (string | null) — the key exists but its value can be null. .nullish() combines both (string | null | undefined). Use optional() for missing fields and nullable() for explicitly null values.

Nest z.object() calls: const addressSchema = z.object({ street: z.string(), zip: z.string() }); const userSchema = z.object({ name: z.string(), address: addressSchema }); Zod deeply validates the nested object and infers the full nested TypeScript type automatically.

Yes — Zod is isomorphic (works in Node.js and browsers). A common pattern is to define schemas in a shared package and import them in both your API (for request validation) and your frontend (for form validation). This eliminates duplicated validation logic and keeps types in sync automatically.