Zod 4

If you're upgrading to Zod 4, this is your migration guide. The big changes are straightforward: email, uuid, and url validators moved from string methods to top-level functions, and nonempty() became min(1). Beyond that, you get solid patterns for discriminated unions, transformations with coerce and preprocess, and the new error parameter syntax that replaces the old message approach. The React Hook Form integration example is handy if you're doing form validation. It's basically a cheat sheet organized around the breaking changes, so you spend less time in the docs when something that worked in v3 suddenly throws errors.

skills.sh installs: 236
GitHub stars: 665
last updated: Aug 21, 2026

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Install

$ npx -y skills add gentleman-programming/gentleman-skills --skill zod-4 --agent claude-code

Installs into .claude/skills of the current project.

Files

Breaking Changes from Zod 3

// ❌ Zod 3 (OLD)
z.string().email()
z.string().uuid()
z.string().url()
z.string().nonempty()
z.object({ name: z.string() }).required_error("Required")

// ✅ Zod 4 (NEW)
z.email()
z.uuid()
z.url()
z.string().min(1)
z.object({ name: z.string() }, { error: "Required" })

Basic Schemas

import { z } from "zod";

// Primitives
const stringSchema = z.string();
const numberSchema = z.number();
const booleanSchema = z.boolean();
const dateSchema = z.date();

// Top-level validators (Zod 4)
const emailSchema = z.email();
const uuidSchema = z.uuid();
const urlSchema = z.url();

// With constraints
const nameSchema = z.string().min(1).max(100);
const ageSchema = z.number().int().positive().max(150);
const priceSchema = z.number().min(0).multipleOf(0.01);

Object Schemas

const userSchema = z.object({
  id: z.uuid(),
  email: z.email({ error: "Invalid email address" }),
  name: z.string().min(1, { error: "Name is required" }),
  age: z.number().int().positive().optional(),
  role: z.enum(["admin", "user", "guest"]),
  metadata: z.record(z.string(), z.unknown()).optional(),
});

SKILL.md on GitHub