Zod | Zod

The zod/v4 package is the "flagship" library of the Zod ecosystem. It strikes a balance between developer experience and bundle size that's ideal for the vast majority of applications.

If you have uncommonly strict constraints around bundle size, consider Zod Mini.

Zod aims to provide a schema API that maps one-to-one to TypeScript's type system.

import * as z from "zod";

const schema = z.object({
  name: z.string(),
  age: z.number().int().positive(),
  email: z.string().email(),
});

The API relies on methods to provide a concise, chainable, autocomplete-friendly way to define complex types.

z.string()
  .min(5)
  .max(10)
  .toLowerCase();

All schemas extend the z.ZodType base class, which in turn extends z.$ZodType from zod/v4/core. All instance of ZodType implement the following methods:

import * as z from "zod";

const mySchema = z.string();

// parsing
mySchema.parse(data);
mySchema.safeParse(data);
mySchema.parseAsync(data);
mySchema.safeParseAsync(data);


// refinements
mySchema.refine(refinementFunc);
mySchema.superRefine(refinementFunc); // deprecated, use `.check()`
mySchema.overwrite(overwriteFunc);

// wrappers
mySchema.optional();
mySchema.nonoptional();
mySchema.nullable();
mySchema.nullish();
mySchema.default(defaultValue);
mySchema.array();
mySchema.or(otherSchema);
mySchema.transform(transformFunc);
mySchema.catch(catchValue);
mySchema.pipe(otherSchema);
mySchema.readonly();

// metadata and registries
mySchema.register(registry, metadata);
mySchema.describe(description);
mySchema.meta(metadata);

// utilities
mySchema.check(checkOrFunction);
mySchema.clone(def);
mySchema.brand<T>();
mySchema.isOptional(); // boolean
mySchema.isNullable(); // boolean