Zod v3 → v4 Schema Migration Tool

Why Migrate from Zod v3 to v4?

Zod v4 (released 2025) introduces a major redesign of string format validators. What were previously chained methods on z.string() are now standalone top-level types — resulting in cleaner code, better TypeScript inference, and smaller bundle sizes.

TypeMorph's migration tool handles every format validator change automatically: paste your v3 schemas and get production-ready v4 output in seconds, with a full changelog of every transformation applied.

What Changes in Zod v4

The most impactful breaking change is that string format validators are no longer chained — they become first-class types.

Format Validators — Now Top-Level

// Zod v3
z.string().email()
z.string().url()
z.string().uuid()
z.string().cuid()
z.string().ulid()
z.string().ip()
z.string().base64()
z.string().jwt()

// Zod v4
z.email()
z.url()
z.uuid()
z.cuid()
z.ulid()
z.ip()
z.base64()
z.jwt()

ISO Date/Time — Now Under z.iso Namespace

// Zod v3
z.string().datetime()
z.string().date()
z.string().time()
z.string().duration()

// Zod v4
z.iso.datetime()
z.iso.date()
z.iso.time()
z.iso.duration()

Chaining Still Works

All other validators chain the same way. .optional(), .nullable(), .describe(), and constraints like .min() work identically on both the old and new types:

// Zod v3
z.string().email().optional()
z.string().url({ message: "Must be a valid URL" })

// Zod v4
z.email().optional()
z.url({ message: "Must be a valid URL" })

Full Migration Example

// Before (Zod v3)
const UserSchema = z.object({
  id: z.string().uuid(),
  email: z.string().email(),
  website: z.string().url().optional(),
  createdAt: z.string().datetime(),
  birthDate: z.string().date().optional(),
  token: z.string().jwt(),
});

// After (Zod v4) — generated by TypeMorph
const UserSchema = z.object({
  id: z.uuid(),
  email: z.email(),
  website: z.url().optional(),
  createdAt: z.iso.datetime(),
  birthDate: z.iso.date().optional(),
  token: z.jwt(),
});

How TypeMorph's Migration Tool Works

TypeMorph processes your Zod schema code with a syntax-aware parser that correctly handles nested parentheses, quoted error messages, and option objects. Unlike simple find-and-replace, it preserves your entire chain of validators and only transforms the format validator itself.

Every transformation is shown in a live changelog with the original and migrated form side by side, making it easy to review before copying to your codebase.

Complex Chains — Manual Review

When a format validator is chained after other validators (e.g. z.string().min(1).email()), TypeMorph flags these for manual review. In Zod v4, z.email().min(1) is the correct form, but the tool conservatively leaves ambiguous chains unchanged and highlights them.

Complete List of Format Validator Changes