Zod

Zod 4.2 and newer implements both Standard Schema and Standard JSON Schema directly. Pass the schema and nothing else.

import { z } from "zod";
import { compile, decode, encode, fingerprinted } from "shorn";

const Person = z.object({
  name: z.string(),
  age: z.int().nonnegative(),
  sex: z.enum(["M", "F", "X"]),
});

const bytes = encode(Person, person); // 8 bytes
const decoded = decode(Person, bytes);

const PersonWire = compile(Person);                 // reusable codec
const PersonStored = fingerprinted(compile(Person)); // + 3 bytes of identity

Wire mapping

Zod	Wire
z.string()	varint length + UTF-8
z.boolean()	one byte
z.int()	ZigZag varint
z.int().nonnegative()	plain varint
z.number()	float64, always 8 bytes
z.enum([...])	varint index in sorted order
z.literal(...)	zero bytes
z.array(T)	varint count + elements
z.tuple([...])	elements only
z.object / z.strictObject	presence bitmap + values in canonical key order
z.optional()	a bit in the presence bitmap
z.nullable()	discriminator byte + value

Use z.int().nonnegative() when the value cannot be negative. shorn then uses an unsigned varint. For example, 127 takes one byte as a uint and two bytes as a ZigZag-encoded int.

Extra properties

Schema	{ name: "Grace", extra: true }
z.object	encodes; Zod strips extra first
z.strictObject	Zod throws Unrecognized key: "extra"
z.looseObject	refused when the codec is built

z.object and z.strictObject produce the same bytes and fingerprint because both emit additionalProperties: false. z.looseObject and z.record emit additionalProperties: true. Because shorn cannot encode unnamed properties, these schemas fail during codec construction.

Refinements are validated, not encoded

.min, .max, .regex, .refine run on encode and decode and never change a byte. Adding .max(300) does not reissue the fingerprint.

Rich types: z.codec()

z.date() and z.bigint() fail during JSON Schema conversion because JSON Schema cannot represent them. Convert at the application boundary:

const Rich = z.object({
  when: z.codec(z.iso.datetime(), z.date(), {
    decode: (text) => new Date(text),
    encode: (date) => date.toISOString(),
  }),
});

const Wire = z.object({ when: z.iso.datetime() });
const codec = fingerprinted(compile(Wire));

const bytes = codec.encode(z.encode(Rich, value));
const back = z.decode(Rich, codec.decode(bytes));

This requires two calls because Standard Schema has no reverse operation. shorn cannot call Zod’s z.encode without adding validator-specific code. See Date, BigInt, Map, Set.

Async refinements

const bytes = await encodeAsync(Person, person);
const back = await decodeAsync(Person, bytes);

Both functions accept the schema rather than a codec, so async validation does not compose with fingerprinted(). See Validation.

Version note

Zod 4.2 is the floor. Earlier Zod 4 releases lack Standard JSON Schema, so encode throws “provides validation but not structure” — pass { structure } from z.toJSONSchema.