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advanced-8y4qeprMetadata

Last Updated: 3/12/2026

Metadata

Attach custom metadata to schemas for documentation, code generation, or runtime introspection.

Descriptions

Add human-readable descriptions:

import * as z from "zod";
 
const User = z.object({
  email: z.string().email().describe("User's primary email address"),
  age: z.number().int().describe("Age in years"),
});
 
const emailSchema = User.shape.email;
emailSchema.description; // "User's primary email address"

Custom Metadata

Store arbitrary metadata using the global registry:

const Password = z.string()
  .min(8)
  .meta({
    label: "Password",
    placeholder: "Enter your password",
    sensitive: true,
  });
 
const metadata = Password.meta();
// { label: "Password", placeholder: "...", sensitive: true }

Use Cases

Metadata is useful for:

  • Form generation (labels, placeholders, help text)
  • API documentation (descriptions, examples)
  • Code generation (hints for code generators)
  • Custom tooling (schema introspection)

Accessing Metadata

schema.description; // Get description
schema.meta(); // Get all metadata
schema.meta(data); // Set metadata (returns new instance)

What’s Next

  • JSON Schema — Export schemas with descriptions
  • Defining Schemas — Learn schema basics
Common PatternsTransforms