# Metafield owner types

> The resource types a metafield definition can target, each listing the constraints it allows.

A **Metafield owner type** is one of the resource types a [Metafield definition](/api/product-management/metafield-definitions/) can be attached to - `products`, `variants`, and so on. This is a **read-only reference** resource: you list the owner types to discover the valid values for a definition's `ownerType`.

Each owner type also reports its **`allowedConstraints`** - the constraint types you may attach to a definition with that `ownerType`. Constraints depend on the **owner type**, not on the data type, so this resource is the authoritative source for constraint compatibility (see [Type compatibility](/api/product-management/metafield-definitions/#type-compatibility)). Today only `products` allows constraints; other owner types return an empty list.

## The Metafield owner type object

## Conventions

All requests require an OAuth 2.0 bearer token and the organization scope header:

```
Authorization: Bearer <token>
X-Flowkiwi-Organization-Id: <organization-id>
```

This resource is read-only - it has no create, update or delete operations.