ArkType

ArkType 2.1.28 and newer implements both Standard Schema and Standard JSON Schema directly. Pass the type and nothing else.

import { type } from "arktype";
import { decode, encode } from "shorn";

const Person = type({
  name: "string",
  age: "number.integer >= 0",
  sex: "'M' | 'F' | 'X'",
});

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

An equivalent Zod schema produces the same bytes and fingerprint.

Wire mapping

ArkType	Wire
"string"	varint length + UTF-8
"boolean"	one byte
"number.integer"	ZigZag varint
"number.integer >= 0"	plain varint
"number"	float64, always 8 bytes
"'M' | 'F' | 'X'"	varint index in sorted order
"'M'"	zero bytes
"string[]"	varint count + elements
["string", "number"]	tuple: elements only
{ ... }	presence bitmap + values in canonical key order
"key?": "string"	a bit in the presence bitmap
"string | null"	discriminator byte + value

Use "number.integer >= 0" when the value cannot be negative. Signed integers use ZigZag encoding and need an extra byte at lower values.

Extra properties

ArkType objects are open by default. Unknown properties pass through validation, and ArkType does not emit additionalProperties: false. shorn therefore checks for extras during encoding and rejects them instead of dropping data. The codec still builds successfully.

Type	{ name: "Grace", extra: true }
type({ name: "string" })	shorn throws Unknown object property "extra"
type({ name: "string", "+": "delete" })	encodes; ArkType strips extra
type({ name: "string", "+": "reject" })	ArkType throws extra must be removed

Use "+": "delete" to strip expected extras, or "+": "reject" to report ArkType’s validation error. Leaving the object open also works because shorn will reject extras during encoding.

The fingerprint excludes rejectUnknown, so equivalent ArkType and Zod schemas still agree even though they handle extra properties differently.

Rich types

Date and bigint fail during JSON Schema conversion, before shorn receives them. ArkType reports { code: "date" } and { code: "domain", domain: "bigint" }. Convert rich values at the application boundary and encode a wire-friendly shape; see Date, BigInt, Map, Set. Standard Schema has no reverse operation, so shorn cannot run an ArkType morph backwards.

A morph is also refused when its input and output produce different wire shapes. shorn requires both sides to agree on the encoded bytes.

Version note

2.1.28 is the floor. Earlier versions lack Standard JSON Schema, so encode throws “provides validation but not structure” — pass { structure }.